WO2009144653A2 - Needle with integrated photon detector - Google Patents

Abstract

The needle is equipped with a battery-operated light source (LS), preferably a light emitting diode, and may comprise at least one light-guiding optical fiber (LGMl) integrated into the hollow shaft (S) of the needle and optically coupled to the light source for transferring light waves from one end on which a beam of input light generated by said light source (LS) is incident to another end located in a tissue region of interest (ROI) to be excised around the tip of said needle (N) which is used for illuminating the tissue in front of the tip of said needle, thereby providing an output light assignable to the intensity of the input light. Furthermore, a collection fiber (LGM2) integrated into the needle hollow shaft for collecting the reflected light from the tissue region of interest reaching the tip of the needle may be provided as well as a battery-operated light detector (LD), integrated into the needle, that is capable of detecting the collected light in at least two non-overlapping spectral bands. An alarm system (AS), which may either be contained within the hollow shaft (S) of said needle and electrically connected or, as an alternative, located in a remote unit (CO) exterior of said needle and wirelessly coupled to said light detector, indicates when the needle (N) is approaching a vital anatomical structure that must be left unscathed and/or when the needle tip has reached the tissue to be excised.

Description

Needle with Integrated Photon Detector

FIELD OF THE INVENTION

The present invention relates to a surgical or biopsy needle (N) for being percutaneously introduced into tissue of a patient.

The invention further relates to a method for percutaneously introducing a surgical or biopsy needle (N) into tissue of a patient.

BACKGROUND OF THE INVENTION

Nowadays, percutaneous image-guided core needle biopsy is being increasingly used to diagnose non-palpable pathological tissue anomalies (such as e.g. tissue structures indicative of breast lesions, prostate cancer or other types of cancerous tissue such as e.g. given by benign tumors and malignant, metastasic carcinomas, sarcomas or lymphomas) in the interior of a patient's body. Compared to surgical biopsy, this procedure is less invasive, less expensive, faster, minimizes deformity, leaves little or no scarring and requires a shorter time for recovery. Needle biopsy can obviate the need for surgery in women with benign lesions and reduce the number of surgical procedures performed in women with breast cancer. However, needle biopsy implies the disadvantage of having a limited sampling accuracy since usually only a few small pieces of tissue are extracted from random locations in the suspicious mass. In some cases, sampling of the suspicious mass may be missed altogether. Consequences include a relatively high false-negative rate (when verified with follow-up mammography) and the necessity of executing repeat biopsies (percutaneous or surgical) in a large amount of cases (due to discordance between histological findings and mammography). The sampling accuracy of core needle biopsy is highly dependent on operator skills and on the equipment used.

Percutaneous image-guided interventional procedures are usually performed on pre-interventionally acquired diagnostic scans that are not necessarily contrast enhanced, such as e.g. acquired by MR- or CT-based imaging techniques which make it possible to display a localized focus of a tissue anomaly within the interior of a patient's body. A typical example for this is mammographic visualization of non-palpable pre-cancerous lesions and tumors in the breast of a woman. In order to accurately diagnose and effectively treat the cancer, it may be necessary for a surgeon to excise a portion of the diseased tissue for histological and/or cytological analysis by microscopic examination. For surgical removal of cancerous tissue under image-guided percutaneous intervention, it is of great importance not to cut through the tumor. During an image-guided interventional or surgical procedure, needle advancement typically poses a potential danger due to the following conditions: a) non- familiarity with oblique cross-sectional anatomy and b) non- familiarity with the exact location of blood vessels and inadvertent vital anatomical structure transgression that can lead to significant hemorrhage, organ injury, pain and infection. In contrast to local bleedings in peripheral interventional procedures, which require no treatment and resolve without complication, small bleedings in the neurologic biopsies, ablations or neurostimulations can be lethal.

Lesion access trajectory planning, which has especially become necessary in variety of neurointerventional or neurosurgical procedures, is considered a major clinical problem today due to the following issues: intervening structures and important vessels that can be unavoidably traversed along the needle path and/or not having a real-time feedback on the needle location with respect to the vital anatomical structures. Therefore, safe access to different brain lesions should be based on a well established trajectory line that should not traverse vessel structures (both arteries and veins). Due to the extremely well developed vascular microstructure within the brain parenchyma, almost every advancement of a brain biopsy, ablation or neurostimulation needle causes a series of microstrokes along the path of the needle through the tissue. Contrary to small microstrokes that may spontaneously occlude, rupturing of somewhat bigger vessels can cause irreversible intracranial hemorrhage that is often lethal. Apart from brain interventions, any other type of percutaneous intervention would improve when during the advancement of the needle important structures could be left unscathed or when confirmation that the site of interest is reached is available. In the scope of a percutaneous minimally invasive intervention, non-palpable lesions are traditionally excised by means of a guiding tool equipped with a hook wire, which greatly facilitates image-guided needle biopsy and surgical resection by providing radiologists with a long wire marker having a small hook portion or spur at one end to be located into the tissue under radiological control. Once the wire hook has been inserted into a tissue region of interest, an X-ray image is taken to document the exact relationship of the hook portion to the target lesion. The wire length thereby serves as a marker and guides the surgeon to a suspected lesion or node. Presuming that the wire guide has been accurately positioned, an image-guided needle biopsy based on X-ray, MRI, CT, sonography or hybrid radiography/MR imaging can be performed rapidly and accurately. Unfortunately, if the wire guide is shown by radiological examination to be improperly situated, one or more additional hooked wires must be inserted into the cancerous tissue and subsequently verified under radiological control as being in the proper localized site. Once inserted, accurately or inaccurately, it is usually the surgeon who will remove the wire markers at the time of biopsy because the hooked end of the wire is embedded in the cancerous tissue and cannot easily be withdrawn without injuring surrounding healthy tissue regions.

A wide variety of different wire guides and needle devices have been developed to aid the surgeon in the biopsy procedure and are in routine use today. From the prior art, four basic types of conventionally available wire guide devices are known that are typically used for marking and localizing the position of a cancerous tissue region of interest to be excised are known and to be distinguished: the Frank localizer, the Kopans locater, the Homer needle/wire localizer and the Sadowsky needle marking system. For further information on these biopsy needles, the interested reader is referred to the relevant literature. For example, WO 99/51143 describes a localization hook wire which is equipped with a light source attached to it, the latter being used to better localize the tumor and to help a surgeon to easier find the center of the tumor. A method according to the invention as proposed and described in this document comprises the steps of percutaneously introducing an illumination source for localizing a target site in solid tissue to be examined and detecting the emitted illumination transmitted through the tissue to mark the target site therein.

To characterize and discriminate different types of pathological tissue anomalies to be excised and analyzed, it is known from the prior art to use optical spectroscopy techniques including ultraviolet-visible (UV-VIS) reflectance and fluorescence spectroscopy as well as near-infrared (NIR) optical spectroscopy. Near-infrared (NIR) optical spectroscopy is a technique in which a light source is located on the tissue surface to be examined, wherein said light source then emits photon density waves having a wavelength from a spectral range between about 600 nm and 1000 nm into the tissue. A fraction of these photons which propagate through the tissue reach a collector located at some distance from the light source. The absorption and scattering properties of the tissue can be retrieved from the amplitude and phase shift of the collected light using a light transport algorithm based on the diffusion equation, wherein the concentrations of absorbers can be derived from the absorption coefficient using Beer's law. Endogenous absorbers in breast tissue at NIR wavelengths include oxyhemoglobin and deoxyhemoglobin, water and lipids. The scattering is associated with microscopic variations in the size, shape and refractive indices of both intracellular and extra cellular components.

Tissue vascularity, hemoglobin concentration and saturation have all been identified as diagnostic markers of breast cancer using a variety of different techniques including immunohistochemistry, needle oxygen electrodes and magnetic resonance spectroscopy. Breast cancers are more vascularized and are hypoxic compared to normal breast tissues. A number of groups have demonstrated that these sources of contrast can be exploited for the non- invasive detection of breast cancer in the intact breast using NIR diffuse optical imaging. For example, Ntziachristos V. et al., as described in the article MRI-Guided Diffuse Optical Spectroscopy of Malignant and Benign Breast Lesions, Neoplasia, 2002, Vol. 4, No. 4, pages 347 - 354, developed and tested a novel hybrid system that combines magnetic resonance imaging and NIR diffuse optical imaging for non- invasive detection of breast cancer. Using this technique, they quantified oxygenated hemoglobin (HbO2) and deoxygenated hemoglobin (Hb) concentrations of five malignant and nine benign breast lesions in vivo. The average total hemoglobin concentration for the cancers, fibroadenomas and normal tissues were 0.130 ± 0.100 mmoH-1, 0.060±0.010 mmoH-1 and 0.018±0.005 mmoH-1, respectively. This representative study demonstrates that NIR diffuse optical methods can discriminate malignant from benign lesions based on tissue vascularity.

Ultraviolet-visible (UV-VIS) reflectance and fluorescence spectroscopy (RFS) is a combination of two techniques. Reflectance spectroscopy is a technique in which broad spectrum light containing wavelengths from 350 nm to 600 nm illuminates the tissue. The reflected light is collected, separated into its component wavelengths and measured. This enables us to examine several chemicals which absorb light including oxyhemoglobin, deoxyhemoglobin and beta-carotene. Fluorescence spectroscopy is a technique where a single wavelength is used to illuminate the tissue. The illumination light is absorbed by endogenous and/or exogenous chemicals in the body, then re-emitted as fluorescence light at a different wavelength. This re-emitted light is collected and measured. This may for example be done for a series of illumination wavelengths of light in the spectral range between 300 nm and 460 nm. Fluorescence spectroscopy allows us to characterize several tissue components such as flavin adenine dinucleotide (FAD), reduced nicotinamide adenine dinucleotide (NADH), collagen and tryptophan. These two techniques can be done in rapid succession with a single instrument.

All of the above-described optical spectroscopy techniques require that the light source and light detector are positioned close to the tissues to be examined. In both methods, the measured properties are averages of all the tissues where the light has traversed. In the former method, small areas inside large tissues can be difficult to distinguish without complex imaging techniques. The UV-VIS light used in the latter method does not penetrate deeply into human tissue and this is typically used to examine the surface of tissues. The light may also be delivered to a tissue through an optical fiber that extends through an endoscope such as that described in US 5,131,398 to examine the surface of an internal organ.

US 2005 / 0203419 Al describes a method and optical probe for making optical spectroscopy measurements during the performance of a core needle biopsy. The optical probe is inserted into the biopsy needle after the needle has been inserted into the candidate tissue to be biopsied. Light is applied to the probe and is emitted into tissue surrounding the tip of the biopsy needle, and light from these tissues is collected by the probe and conveyed to a spectroscopy instrument for analysis. When a target tissue is detected, the probe is removed from the biopsy needle and a tissue sample is acquired by advancing a cutting tool.

SUMMARY OF THE INVENTION

Conventional concepts for histological and cyto logical analysis of tissue characteristics with a biopsy needle equipped with optical fϊber(s) suffer from the following drawbacks: Firstly, the fiber must be physically connected to an operator console containing a spectrometer, and, secondly, the physical wire connection between the biopsy needle and the spectrometer may be inconvenient to the physician as it may potentially limit needle movement range, decrease lesion targeting accuracy and may potentially interfere with other cabling such as e.g. needed in operating rooms for patient monitoring equipment, thus hindering the surgeon's work. It may thus be an object of the present invention to provide for a more comfortable, cost-effective way of performing percutaneous image-guided needle biopsies for a subsequent histological and surgical resection of cancerous and other pathological tissue anomalies, which does not need any cables and is capable of indicating when tissue to be left unscathed appears in front of the needle and/or when a targeted tissue region of interest to be excised is reached.

To address this object, a first exemplary embodiment of the present invention refers to a surgical or biopsy needle for excising non-palpable pathological tissue anomalies (such as e.g. tissue structures indicative of breast or prostate cancer or other types of pathological tissue anomalies, benign tumors and malignant, metastasic carcinomas, sarcomas or lymphomas) in the interior of a patient's body under X-ray, CT, MR, sonography or hybrid radiography/MR based image guidance after being percutaneously introduced into this tissue. According to the invention, said needle may comprise a hollow shaft longitudinally extending within the interior of the needle with at least one first inserted light guiding means (e.g. an optical fiber) for transferring beams of an input light emitted by a light source from a proximal end on which said input light is incident to a distal end located within a tissue region of interest around the tip of said needle, thereby providing an output light assignable to the intensity of the input light for illuminating said tissue region. Moreover, at least one second inserted light guiding means (e.g. a further optical fiber) may be provided for guiding the back-scattered light reflected from the tissue region of interest to a light detector located at a proximal end of said at least one second inserted light guiding means. It may thereby be foreseen that said light detector has an output interface connected to an alarm system which, if necessary, generates a warning signal for indicating when the needle is approaching an intervening anatomical structure lying in the navigation path of said needle that must be left unscathed and/or when the tip of the needle has reached a pathological tissue anomaly to be excised.

The first light guiding means and the second guiding means may be comprised by a single apparatus. Thus, the first light guiding means and the second light guiding means may have a physical common part. In other words, the first light guiding means and the second light guiding means may describe two directions for a light within a single light guiding apparatus. For example, a single fiber, in particular a single optical fiber, may be used, wherein the single fiber may be adapted to guide a light in the direction towards the tissue and to guide a reflected light to the light detector. Thus, the light and the reflected light may be overlaid or heterodyned within the single guiding apparatus. Thus, the same fiber may be used to illuminate and to collect the light back. At the proximal end the light from the source may be coupled into the fiber and the reflected light coming back via the fiber may be redirected towards the detector. For example, an optical mixer, a prism, a semitransparent mirror or a semi permeable mirror may be used for coupling and/or separating the incident light and the reflecting light. Alternatively, the first light guiding means and the second light guiding means may be separate devices. For example, the first light guiding means and the second light guiding means may be at least two optical fibers. Thus, the first light guiding means and the second light guiding means may be locally separated or spaced apart. The local separation may allow positioning the illumination point and the light detection point at different positions.

Said light source may either be realized as a battery-operated light emitting diode or a battery-operated semiconductor laser integrated in the interior of said hollow shaft or as an incandescent light bulb, a high-intensity discharge lamp, a light emitting diode or semiconductor laser located exterior to said patient's body, wherein said light source is optically coupled to the proximal end of said at least one first inserted light guiding means.

The aforementioned light detector, which may be optically coupled to the proximal end of said at least one second inserted light guiding means, may either be given by a battery-operated photosensor integrated in the interior of said hollow shaft or by a photosensor located exterior to said patient's body. According to the present invention, said light detector may e.g. be realized as a detector array comprising a number of (e.g. between 5 and 10) photosensitive diodes connected to a set of narrowband interference filters which may be integrated on top of the diodes. The invention is thereby based on the fact that the absorption spectrum of blood shows characteristic peaks in the visible spectrum of light at wavelengths in the range between around 400 nm and 600 nm. According to the invention, the absorption coefficient of light waves incident on an intervening tissue (such as e.g. a blood vessel) lying in the navigation path of said needle is measured in at least two non-overlapping spectral bands: one in a spectral band around the absorption peak (for instance at wavelengths in a range between 520 nm and 540 nm) and another one in a spectral band farther away from the peak (for instance at wavelengths in a range between 620 nm and 640 nm). It may thus be provided that said light detectors are capable of detecting collected light in the aforementioned two spectral bands or in more than two non-overlapping spectral bands, respectively. The impulse responses of said interference filters may thereby be chosen such that the passbands of the filters are in the optical range of interest for accurate detection of the desired wavelength bands. The proposed circuit design results in a robust, compact sensor which can be produced in a standard silicon process.

The ratio of these absorption values may be used as a blood vessel monitor signal which indicates whether the needle is approaching a vital anatomical structure which should be left unscathed and/or when the needle tip has reached the tissue region of interest. Such a relative measurement implies the advantage that it is insensitive to intensity deviations of the surrounding light. According to a first aspect of this embodiment, said alarm system may be integrated in the interior of the hollow shaft at the proximal end of said needle and electrically connected to said light detector, whereas, according to a second aspect, said alarm system may be located exterior to said patient's body and wirelessly coupled to a wireless transmitter integrated in the interior of said hollow shaft at the proximal end of said needle. The wireless transmitter thereby serves for providing said alarm system with the output signal of the light detector over the air interface.

The warning signal may e.g. be given by an optical signal generated by a single monochromatic light emitting diode or by an integrated LED array of said alarm system, wherein said LED array may comprise a number of monochromatic light emitting diodes each being capable of emitting light waves in a different band of the visible spectrum of light and thus producing light beams of a different color and/or intensity indicative of the distance between said needle and an intervening anatomical structure to be left unscathed lying in the navigation path in front of said needle when advancing the needle in a direction towards the tissue region o f interest.

As an alternative thereto, said warning signal may be given by an acoustic signal generated by an integrated loudspeaker of said alarm system whose frequency and/or loudness is indicative of the distance between said needle and an intervening anatomical structure to be left unscathed as mentioned above when advancing the needle in a direction towards the tissue region of interest.

In the first case, said alarm system may be configured to vary the color or intensity of the optical signal and/or the switching frequency of an on-off keying sequence modulating the optical signal which encodes the information to be conveyed by this signal depending on the intensity of the back-scattered light waves reflected from the intervening anatomical structure lying in the navigation path in front of said needle such that a surgeon is warned not to further advance said needle in the direction towards the intervening anatomical structure. It may also be foreseen that the color or intensity of the optical signal and/or the switching frequency of an on-off keying sequence modulating the optical signal which encodes the information to be conveyed by this signal is/are varied depending on the intensity of the back-scattered light waves reflected from the tissue region of interest to be excised lying in the navigation path in front of said needle such that a surgeon is guided to further advance said needle in the direction towards this tissue region.

In the alternative case, the alarm system may be configured to vary the frequency or loudness of the acoustic signal and/or the switching frequency of an on-off keying sequence modulating the acoustic signal which encodes the information to be conveyed by this signal depending on the intensity of the back-scattered light waves reflected from the intervening anatomical structure lying in the navigation path in front of said needle such that a surgeon is warned not to further advance said needle in the direction towards the intervening anatomical structure. Analogously, it may also be foreseen that the frequency or loudness of the acoustic signal and/or the switching frequency of an on-off keying sequence modulating the acoustic signal which encodes the information to be conveyed by this signal is/are varied depending on the intensity of the back-scattered light waves reflected from the tissue region of interest to be excised lying in the navigation path in front of said needle such that a surgeon is guided to further advance said needle in the direction towards this tissue region.

In any case, however, it may be provided that the intensity of the optical signal, the frequency and/or loudness of the acoustic signal and the switching frequency of the on-off keying sequence modulating the optical or acoustic signal are respectively configured to be more or less penetrating depending on the distance between the tip of said needle and the intervening anatomical structure or tissue region of interest to be excised.

A second exemplary embodiment of the present invention is dedicated to an operator console which comprises a wireless receiver for receiving the detector output signal of a surgical or biopsy needle as described above with reference to said first exemplary embodiment via the air interface and converting this output signal into a warning signal which is then to be indicated to an operator.

In addition to that, said operator console may comprise an image processing unit configured for fusing the received detector output signal with acquired image data supplied by an ultrasound, X-ray, CT or MRI system or any hybrid type of radiographic and/or nuclear medical imaging system.

Furthermore, said operator console may include a spectrograph for graphically visualizing the reflected light spectra as detected by said light detector on a monitor screen or display.

Finally, a third exemplary embodiment of the present invention is directed to a method for excising non-palpable pathological tissue anomalies in the interior of a patient's body under image guidance by means of a surgical or biopsy needle percutaneously introduced into this tissue. Said method may thereby comprise the steps of transferring beams of an input light emitted by a light source from a proximal end exterior of said patient's body on which said input light is incident to a distal end located within a tissue region of interest around the tip of said needle by means of a first light guiding means inserted into a hollow shaft of said needle, thereby providing an output light assignable to the intensity of the input light for illuminating said tissue region, and, by using a second light guiding means inserted into the hollow shaft, guiding the back-scattered light reflected from a tissue lying in the navigation path of said needle to a light detector located at a proximal end of said second light guiding means. After having measured the intensity of the back-scattered light by means of said light detector and if necessary, a warning signal is generated for indicating when the needle is approaching an intervening anatomical structure to be left unscathed and/or when the tip of the needle has reached a pathological tissue anomaly to be excised. According to a further aspect of this embodiment, said method may additionally comprise the step of guiding a liquid given by a targeted contrast agent or dye fluorescent in the visible spectrum of light to the tip of said needle via a cannula with a substantially tubular wall and an internal lumen having an open distal end similar to the needle of a hypodermal syringe, said cannula being inserted into the hollow shaft of said needle.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other advantageous aspects of the invention will be elucidated by way of example with respect to the embodiments described hereinafter and with respect to the accompanying drawings, wherein,

Fig. 1 shows a system configuration as known from the relevant prior art for performing a percutaneous image-guided needle biopsy in conjunction with an optical spectroscopy for analyzing a pathological tissue of interest to be excised,

Fig. 2 shows a schematic drawing for illustrating an sonography-guided needle biopsy taken from a patient's prostate via the rectum,

Fig. 3a shows a surgical or biopsy needle according to a first exemplary embodiment of the present invention which may be used for excising non-palpable pathological tissue regions or any kind of tissue anomalies in the interior of a patient's body during an image-guided surgical or minimally invasive interventional procedure, said needle being equipped with an alarm system attached and electrically connected to an integrated light detector which indicates when the needle is approaching a vital anatomical structure that must be left unscathed and/or when the needle tip has reached the tissue to be excised

Fig. 3b shows on the left a schematic 3D view of the light detector from the embodiment depicted in Fig. 3a comprising a detector array equipped with a number of photodiodes and an associated interference filter array, wherein said photodiodes are arranged in square sized detector fields composed of a stack of different layers, and on the right of this figure a set of filter characteristics indicating the transmission coefficient of said interference filters around a wavelength of interest in the visible spectrum of light is shown, Fig. 3c shows a surgical or biopsy needle according to a second exemplary embodiment of the present invention wirelessly coupled to an alarm system located at the site of an operator console, said needle comprising an integrated light detector as described with reference to the setup configuration depicted in Fig. 3a wirelessly coupled to an alarm system located at the site of an operator console, Fig. 4a shows the absorption coefficient of a sample probe (such as e.g. blood) over the entire spectral range including the characteristic absorption band in the visible spectrum of light,

Fig. 4b shows a diagram which provides a more detailed view of the absorption spectrum for the blood sample probe of Fig. 4 in the visible spectrum of light between 400 nm (violet) and 700 nm (red),

Figs. 5a+b show two cross-sectional schematic diagrams of the surgical or biopsy needle according to the first exemplary embodiment of the present invention having at least one light guiding optical fiber for guidance of biopsy and at least one collecting fiber for determining the presence of blood vessels and other types of vital anatomical tissue that must be left unscathed as well as the associated diagrams for illustrating the corresponding detected absorption bands in the visible spectrum of light obtained for two different distances between said needle and a blood vessel lying in the navigation path in front of said needle,

Fig. 6 shows the exemplary configuration setup according to said second exemplary embodiment as depicted in Fig. 3c in a more schematic way, and Fig. 7 shows a flow chart for illustrating the claimed method according to the present invention.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

In the following sections, the claimed surgical or biopsy needle, the operator console as well as the associated method mentioned above will be explained in more detail with respect to special embodiments referring to the accompanying drawings and in comparison to the relevant prior art. It should be understood, however, that the embodiments are not intended to limit the invention to the particular setup disclosed, but that the intention is to cover advantageous modifications, equivalents and alternatives falling within the spirit and scope of the present invention as defined by the appended claims.

In Fig. 1, a prior-art system configuration for performing a percutaneous image-guided needle biopsy in conjunction with an optical spectroscopy for analyzing a pathological tissue of interest to be excised as known from US 2005 / 0203419 Al is shown. The depicted system configuration thereby comprises an optical spectrometer OSP, a side firing fiberoptic probe FOP, which may e.g. be covered with a flexible tubing FT, and a biopsy needle N shown in a longitudinal cross-sectional view. The optical spectroscopy system thereby comprises a light source LS that connects to the proximal end of an illumination optical fiber (in the following also referred to as ,,first light guiding means" LGMl) and is operated by a controller CTR to generate light from a defined spectral range which is then emitted from the distal end of the fiberoptic probe FOP. The controller CTR also operates the optical spectrometer instrument OSP which receives light through a detector optical fiber (in the following also referred to as ,,second light guiding means" LGM2) having a distal end fastened to said fiberoptic probe FOP. The diameter of the probe is sufficiently small that it can be inserted into a central channel formed in a needle shank NS. In this configuration, a breast biopsy needle such as e.g. that disclosed in US 6,638,235 and manufactured by Suros Surgical Systems, Inc. may be employed. Needle shank NS extends completely through a handle H that contains a mechanism for extracting a tissue sample through needle N. A sample holder SH attached to a connector CN on the proximal end of handle H is removed during the optical data acquisition portion of the procedure to provide access to the proximal end of the needle shank NS for the fiberoptic probe. When this step of the procedure is completed, fiberoptic probe FOP is withdrawn and sample holder SH is reattached. When the fiberoptic probe is properly positioned at the distal end DE of needle shank NS, the distal ends of both optical fibers LGMl and LGM2 are aligned axially along the longitudinal axis of said needle with a window W formed by an opening in the shank NS of the needle near its distal end DE. This window may be used during the biopsy procedure for tissue collection. The distal end of illumination optical fiber LGMl may e.g. be beveled at an acute angle such that light emanating from light source LS and traveling through the fiber LGMl is reflected radially outward through window W into the surrounding tissue.

The distal end of the detection optical fiber LGM2 is similarly beveled at an acute angle. As a result, light entering through window W in a substantially radially inward direction is reflected off the beveled end and is redirected axially along the optical fiber LGM2. Illumination of tissues located in the region outside said window is thus performed by conveying the desired light along fiber LGMl and collecting the resulting light produced in these tissues by means of optical fiber LGM2. The collected light is then conveyed back to optical spectrometer OSP by the detector optical fiber LGM2. Tissues surrounding the distal tip of biopsy needle N can thus be spectroscopically examined by rotating the needle about its longitudinal axis to ,,aim" the window W in a succession of radial directions.

During a percutaneous image-guided needle biopsy procedure, biopsy needle N is advanced into a patient's tissue region to be examined and its distal end DE is guided to the target tissues using an imaging modality such as ultrasound, CT or MRI system. A fiberoptic probe FOP may then be inserted into the shank NS of the needle and oriented as described above so as to acquire optical information for the optical spectrometer OSP. This may be repeated using the same or a different probe until a decision is made to biopsy. The fiberoptic probe is then withdrawn from the needle shank NS. After that, a gentle vacuum is applied to the needle, thereby pulling a small amount of tissue into the window W. A cutter (not shown) is then advanced which slices this tissue where it enters the needle. The vacuum then pulls this sample of tissue down the needle's length and into a collection chamber. It can be appreciated that by performing optical spectroscopy through window W on the very same tissue that is removed by the biopsy step, highly reliable clinical information is acquired.

An example for a conventional image-guided needle biopsy is shown in Fig. 2, where a needle biopsy is taken under image control from a patient's prostate P via the rectum. In order to find the correct position to take the biopsy, various imaging modalities and methods may be used, such as e.g. X-ray, CT, MR, sonography or hybrid radiography/MR imaging. In case of prostate cancer, a needle biopsy is usually guided by a sonography, which in case of sonography requires an ultrasound probe UP (cf. Fig. 2). Although helpful, these methods of guidance are far from being optimal. On the one hand, resolution is limited, and in most cases these imaging modalities are not able to discriminate between benign and malignant tissue. As a result, a surgeon does not know for certain that a biopsy is taken from the correct part of a tissue region to be examined. Hence, biopsies are taken almost blind and even if after inspection of the tissue no cancerous cells are detected, the surgeon does not know for certain that he/she did not simply miss the right spot to take the biopsy.

If the biopt taken appears to be cancerous, this cancerous tissue will typically be removed by surgery (especially when the tumor is well localized). Here another problem arises due to the fact that the surgeon can only use his/her eyes and hands (palpation) to find the tumor. If the tumor is large enough and if the center of the tumor is more compact than the surrounding tissue, it can be localized by palpation during surgery. Tissue can removed with an apparently sufficient margin around it. However, in a considerable number of cases the tumor is still soft and very difficult to feel or distinguish by eye. To help the surgeon, a wire is inserted into the respective tissue region, e.g. under X-ray, CT, MR, sonography or hybrid radiography/MR imaging guidance, with the end point of the wire located at the center of the tumor.

As described above, it is particularly difficult to find the boundaries of the tumor, in fact it is virtually impossible. The surgeon therefore removes a significant amount of tissue around the tumor center to be sure that all of the tumor is removed. Although removing an additional amount of tissue around the tumor will indeed lead in most cases to complete removal, the surgeon can never be sure. The number of recurrences of the cancer after removal is high, for example 30 %, which already shows that not enough tissue has been removed. One could of course increase the amount of tissue to be removed, but in several cases this turned out to be very difficult. In some cases, vital anatomical structures are present in the tissue (such as e.g. nerves, important blood vessels, brain tissue, etc.). The surgeon has then to decide whether the malfunctioning due to the additional tissue outweighs the risk of not completely removing the tissue. It is important to note that when resection is not complete, the surgeon has, in fact, cut through the tumor and as a result has caused the tumor to spread. A second operation to repair these damages is very invasive and leads to severe side effects such mutilation and loss of function of body and/or mind.

A third problem with the current way of removing tumors by surgery is that although a resection was complete according to the diagnosis of the current methods of pathology, the tumor boundaries may still contain pre-metastasic cells. These cells, which are still not so far developed that they can be diagnosed as being cancerous, may develop in cancer soon, thus being again the cause of tumor recurrence.

Associated with tumors and tumor removal is the spreading of cancerous cells into a patient's lymph nodes. Nowadays, the lymphatic system can be stained by using methylene blue injected at the site of the tumor, and in this way the sentinel node can be located. It is then removed and pathologically investigated. In a plurality of cases the node is affected by the tumor, and all neighboring lymph nodes are removed as well. It should be noted that lymph nodes are embedded in fatty tissue, which has the same pale yellowish color, and cannot be found by eye unless they are stained. Resection of suspicious lymph nodes is radical: All nodes are removed including the surrounding fatty tissue. It should be noted that the surgeon and the patient would be helped enormously if only those lymph nodes could be identified that actually need to be removed because they host cancerous cells.

Fig. 3a shows a surgical or biopsy needle N according to a first exemplary embodiment of the present invention which may e.g. be used for excising non-palpable pathological tissue regions or any kind of tissue anomalies in the interior of a patient's body during an image-guided surgical or minimally invasive interventional procedure for later histological and/or cytological analysis by microscopic examination. The depicted needle comprises a hollow shaft S longitudinally extending within the interior of the needle with at least one inserted first light guiding means LGMl that ends at the tip of the needle (in the following also referred to as "illumination optical fiber" to be consistent with the embodiment as depicted in Fig. 1) for transferring beams of an input light emitted by an integrated battery-operated light source LS (such as e.g. a light emitting diode or semiconductor laser) disposed within an internal lumen of the hollow needle shaft from a proximal end exterior of said patient's body on which said input light is incident to a distal end located within a tissue region of interest to be excised around the tip of said needle and illuminating the tissue in front of the tip of the needle, thereby providing an output light assignable to the intensity of the input light for illuminating said tissue region.

The depicted needle N further comprises at least one second light guiding means LGM2 (in the following also referred to as "collecting fiber" or "detector optical fiber" such as denoted in the embodiment as depicted in Fig. 1) extending within the hollow shaft S of said needle and being connected to a cost-effective battery-operated light detector LD located at the proximal end in the interior of the hollow needle shaft. This detector, which may advantageously be used for detecting collected light waves back-scattered from a tissue region lying in the navigation path of said needle and being illuminated with said input light in at least two non-overlapping spectral bands, provides an output signal which indicates when the needle is approaching a vital anatomical structure (such an artery or vein) that must be left unscathed and/or when the needle tip has reached a tissue of interest to be excised (herein also referred to as ,,sample probe" or ,,sample object" and denoted with reference symbol "O"). Collecting fiber LGM2 is thereby used for guiding the collecting light waves reflected from said tissue that are reaching the tip of the needle. As described above, said light detector LD may be realized as a detector array comprising a number of (e.g. between 5 and 10) photosensitive diodes connected to a set of narrowband interference filters (not shown) which may be integrated on top of the photodiodes. The impulse responses of said interference filters may thereby be chosen such that the passbands of the filters are in the optical range of interest for accurate detection of the desired wavelength bands. The proposed circuit design thereby results in a robust, compact sensor which can be produced in a standard silicon process.

According to the embodiment as depicted in Fig. 3a, said needle N may be equipped with an alarm system AS attached and electrically connected to said light detector LD which indicates when the needle is approaching a vital anatomical structure (such as e.g. an artery or vein) that must be left unscathed and/or when the needle tip has reached a tissue of interest to be excised. Depending on the intensity of the back-scattered light waves reflected from said sample object or any other tissue or anatomical structure (such as e.g. an artery or vein) lying in the navigation path in front of said needle, the alarm system AS will generate a warning signal for the surgeon not to further advance said needle which will be more or less penetrating depending on the distance between the tip of said needle and the aforementioned object or tissue. The alarm system AS may thereby comprise an integrated array LA of light emitting diodes, each being capable of generating an optical signal by emitting light waves in a different band of the visible spectrum of light and thus producing light beams of a different color and/or intensity, and/or an integrated loudspeaker SP for generating an acoustic signal, wherein both said optical signal and said acoustic signal are indicative of the distance between said needle and an object lying in the navigation path of said needle when being advanced within a tissue. For example, an acoustic signal whose intensity and/or basic frequency may vary depending on said distance may be generated. Alternatively or in addition to that, an optical signal consisting of a light beam radiated by a respective one from a number of LEDs capable of emitting visible light in the red, yellow and green spectral range as contained in said LED array LA may be generated. It may e.g. be foreseen that the yellow LED is switched on when the needle is navigated into a given range in the vicinity of a tissue, vessel or any kind of anatomical object to be not excised and that the red LED is switched on when the needle comes in touch with it, whereas the green LED is switched on and remains in the switched-on state as long as the surgeon navigates said needle in an allowed range which is far enough from a tissue, vessel or any kind of anatomical object which has to be left unscathed.

Optionally, additional information about the position of a tumor or lesion lying in the navigation path in front of said needle may be found by means of an optical modality, such as e.g. a mini-camera (not shown), coupled to the distal end of hollow needle S shaft which provides a surgeon with image information needed to probe the dignity of the tissue at the tip of said needle. This allows to guide needle N until a pathological tissue anomaly which may e.g. exhibit cancerous tissue properties has been found.

In a further (optional) refinement of this embodiment, a hook wire HW, which may also be inserted into the hollow needle shaft S, may serve as a guiding tool, which thus greatly facilitates the process of localizing said needle when taking a biopt or in case of surgical resection of a detected tissue anomaly. The hook wire may thereby consist of a long wire marker having a small hook portion or spur at one end to be located into the tissue under radiological control. Once the hook wire has been inserted into a tissue region of interest, an X-ray image may be taken to document the exact relationship of the hook portion to a target lesion. The wire length thereby serves as a marker and guides the surgeon to a suspected lesion or node. Presuming that the wire guide has been accurately positioned, image-guided needle biopsy can be performed rapidly and accurately.

Further optionally, a liquid guiding cannula CA with a substantially tubular wall and an internal lumen having an open distal end similar to the needle of a hypodermal syringe which may be used for guiding a targeted contrast agent or dye (such as e.g. 5-amino- 4-oxo-pentanoic acid (C5H9NO3), in the literature commonly referred to as D-aminolevu- linic acid (δ-ALA)) fluorescent in the visible spectrum of light to a tumor site or other pathological tissue anomalies at the tip of the needle may be foreseen to mark these anomalies by means of said contrast agent. Light-guiding optical fiber LGMl thereby provides the light needed for an excitation of this tissue. If stained with an appropriate fluorescent contrast agent and illuminated with the light guided by said optical fiber, a surgeon will be able to see cancerous tissue regions shimmering through surrounding non- pathological tissue. This may help the surgeon to find the boundaries of a lesion and obtain information about the tumor shape and size. When waiting for some time and then illuminating the cancerous tissue by means of the light guiding means, said tissue will produce fluorescence light, thus helping the surgeon to decide on the best resection margin. Instead of providing a surgical or biopsy needle being specially provided with a liquid guiding cannula as described above, the residual free internal lumen of the hollow shaft which is not occupied by the volume of said light guiding means may also serve for providing the contrast agent to the tip of said needle.

A schematic 3D view of the light detector from the embodiment depicted in Fig. 3a comprising a detector array equipped with a number of photodiodes and an associated interference filter array, wherein said photodiodes are arranged in square sized detector fields composed of a stack of different layers (here exemplarily depicted as a detector array consisting of 4x4 photodiodes arranged in sixteen adjacent detector fields covering a square area with a size of 500x500 μm2), is shown in the left part of Fig. 3b. In the depicted setup configuration, said stack (from the top to the bottom) comprises a first mirror layer (e.g. given by a 45 nm silver layer, here exemplarily given by mirror layers MLl to ML5), a dielectric substrate (oxide layer) with various thicknesses (e.g. between 126 nm and 134 nm in a first horizontal direction and e.g. between 162 nm and 170 nm in a second horizontal direction orthogonal to said first direction characterized by a step size of e.g. 2 nm between adjacent detector fields) and another mirror layer MLg (e.g. made of a 45 nm silver layer) underneath the dielectric substrate. In the right part of this figure, a set of filter characteristics indicating the transmission coefficient of said interference filters around a wavelength of interest in the visible spectrum of light between 400 nm (violet) and 700 nm (red) is shown.

In Fig. 3c, a surgical or biopsy needle according to a second exemplary embodiment of the present invention is shown. Just as described with reference to the embodiment sketched in Fig. 3a, the depicted needle N may consist of a hollow shaft S containing a light guiding optical fiber LGMl connected to a battery-operated light source LS (such as e.g. given by an LED or a semiconductor laser) and a collecting fiber LGM2 connected to a light detector LD integrated into the handle of said needle. Furthermore, a light detector integrated into the hollow shaft of said needle is provided which is supplied by the light reflected from a sample object or any other kind of tissue or anatomical structure lying in the navigation path of said needle. The detector thereby provides an output signal which indicates whether the needle is approaching a vital anatomical structure that must be left unscathed and/or when the needle tip has reached the tissue to be excised.

The back-scattered light waves and/or emitted fluorescence light from a liquid contrast agent applied to a tissue region of interest is guided by the detector optical fiber LGM2 to two detector elements as given by two square areas of a photodiode detector array DA as shown in Fig. 3b. In this connection, it shall be assumed that the output light at the proximal end of said detector optical fiber thereby illuminates two adjacent ones of these areas equally.

As briefly mentioned above, the passbands of the interference filters integrate on top of the photodiodes may be chosen as follows: To leave blood vessels unscathed, the present invention proposes to use optical spectroscopy to measure the absorption properties of the tissue directly in front of the needle tip by adding an optical fiber to the needle. The absorption spectrum of blood shows characteristic peaks in the visible spectrum of light between 400 nm and 600 nm, see Fig. 4a (taken from T. Vo-Dinh (Editor-in-Chief), ,,Biomedical Photonics Handbook", CRC Press, London, 2003, see figure 2.16) and Fig. 4b, wherein the latter provides a more detailed view of this absorption spectrum, thereby differentiating between the molar extinction coefficients of oxygenated hemoglobin (HbO2) and deoxygenated hemoglobin (Hb), respectively. From the spectrum measured in front of the biopsy needle we can deduce the presence of blood by monitoring for these peaks in the absorption spectrum. This can be done for instance by measuring the absorption at two wavelengths bands: one around the absorption peak (i.e., in a wavelength range between 520 nm and 540 nm) and one outside the peak (i.e., in a wavelength range between 620 nm and 640 nm). Taking the ratio of these absorption values as a blood vessel monitor signal, it can be found that when the signal significantly changes said needle is approaching a blood vessel. In this way, a physician does not have to measure the absorption signal absolutely, but only relatively.

Instead of having an integrated alarm system AS such as described above with reference to the embodiment as depicted in Fig. 3a, light detector LD is wirelessly coupled to an external alarm system AS located at the site of an operator console CO. Thereby, needle N is equipped with a wireless transmitter WT which serves for transmitting a modulated RF signal indicative of the spectrum of the back-scattered light waves measured by said light detector LD via a transmit antenna TA of said transmitter to a receive antenna RA of a remote wireless receiver WR located at the site of said operator console CO. Such as described with reference to the configuration setup according to the embodiment as depicted in Fig. 3 a, the external alarm system AS may generate a warning signal for the surgeon which will be more or less penetrating depending on the intensity of the back-scattered light waves reflected from said sample object or any other type of tissue or anatomical structure (such as e.g. an artery or vein) lying in the navigation path in front of said needle and thus depending on the distance between the tip of said needle and the aforementioned object or tissue. Just as described above with reference to Fig. 3a, an acoustic signal emitted by a loudspeaker SP whose intensity and/or basic frequency may vary depending on said distance may be generated. Alternatively or in addition to that, an optical signal generated by a certain one from a number of LEDs capable of emitting light in the red, yellow or green spectral range may be generated. Thereby, it may again be foreseen that the yellow LED is switched on when the needle is navigated into a range in the vicinity of a tissue, vessel or any kind of anatomical object to be not excised and that the red LED is switched on when the needle comes in touch with it, whereas the green LED remains in a switched-on state when the surgeon advances said needle within an allowed range which is far enough from any tissue, vessel or any kind of anatomical object that has to be left unscathed.

Figs. 5a+b show two cross-sectional schematic diagrams of the surgical or biopsy needle N according to the first exemplary embodiment of the present invention as described with reference to Fig. 3 a having at least one light guiding optical fiber LGMl for guidance of biopsy and at least one collecting fiber LGM2 for determining the presence of blood vessels and other types of vital anatomical tissue that must be left unscathed. Furthermore, two associated diagrams for illustrating the corresponding detected absorption bands in the visible spectrum of light (500a and 500b, respectively) which are obtained for two different distances between said needle N and a blood vessel BV lying in the navigation path in front of said needle are shown. As an alternative thereto, it may be foreseen that one and the same optical fiber (or a given number of two or more of these fibers) is used to illuminate the tissue in front of the fiber and also serves as a collection fiber for guiding the back-scattered light to light detector LD. Finally, Fig. 6 shows the exemplary configuration setup according to said second exemplary embodiment as depicted in and described with reference to Fig. 3c in a more schematic way, thereby illustrating the process of measuring the absorption spectrum of a tissue of interest (sample object) lying in the navigation path in front of said needle. As can be taken from Fig. 6, the back-scattered light and/or emitted fluorescence light collected by the fiber is guided to a spectrograph which is used for recording the detected absorption spectrum (500a or 500b, respectively). In case a blood vessel is far away the absorption spectrum does not reveal the absorptions peak characteristic for blood (see absorption spectrum 500a in Fig. 5a). However, when a blood vessel approaches the tip of needle, the absorption spectrum will show the absorption peak for blood (see absorption spectrum 500b in Fig. 5b). Once such a signal occurs, the navigational direction for guiding said needle has to be changed such that the peak is absent again.

There are various ways to measure or quantify this signal. One way is to use two semiconductor lasers, one emitting at wavelength λ = 550 nm (green) and the other at wavelength λ = 633 nm (orange). The signal relating to λ = 550 nm probes the peak of blood, while the signal related to λ = 633 nm is rather insensitive. Taking the ratio of these signals as a triggering signal thereby implies the advantage of being insensitive to deviations in the intensity of the surrounding light. When the ratio of these signals lies above a certain threshold level TL, said needle is in close proximity of a blood vessel BV and hence the needle should be redirected. When the signal lies above this threshold level, alarm system AS generates an optical or acoustic alarm signal which warns the surgeon.

One can also imagine to use a calibrated broadband light source covering the wavelength ranges of interest and perform the detection process by using a compact spectral detector as shown in Fig. 3b having an interference filter integrated on top of the photodiode array, wherein the passbands of said filter are advantageously designed such that the desired wavelengths fall within these passbands.

Another conceivable application scenario is where a surgical or biopsy needle as proposed within the scope of the present application is used to detect a lesion of suspicion in a biopsy procedure. The device is similar to that in as described with reference to said first or second embodiment, respectively, with the exception that the needle is advanced towards a tissue having a certain spectral signature instead of leaving it unscathed. In this case, it may e.g. be foreseen that the red LED is switched on when the needle is navigated out of a given range in the vicinity of a tissue, vessel or any kind of anatomical object to be excised (in the following referred to as "target tissue") and that both the red LED and the yellow LED are in a switched-on state as long as the surgeon navigates said needle within said range without coming in touch with a target tissue, whereas the green LED is switched on when the needle comes in touch with it.

Aside from the aforementioned scenario of generating a warning signal by using a LED array which comprises a number of LEDs capable of emitting light waves of different color and/or intensity in the visible spectrum of light, one and the same LED can be used to convey this information by modulating the drive signal of the LED that is picked up by a detector with an on-off keying sequence representing a binary code, wherein said detector may e.g. be installed at the ceiling of the operating room. The detector picks up the signal (which requires direct line of sight in case of an optical signal) and displays the communicated information to an operator console that is positioned somewhere in the operating room. As an alternative or in addition thereto, a wireless transmitter WT integrated into the hollow shaft S of said needle could be foreseen to wirelessly transmit said detector output signal over the air interface to a remote wireless receiver WR at the site of an operator console CO such as described with reference to the configuration setup according to said second embodiment depicted in Fig. 3c.

A flow chart for illustrating the claimed method for excising non-palpable pathological tissue anomalies according to the present invention is depicted in Fig. 7. The proposed method begins with the (optional) step of guiding (Sl) a liquid given by a targeted contrast agent or dye fluorescent in the visible spectrum of light to the tip of said needle N via a cannula CA with a substantially tubular wall and an internal lumen having an open distal end similar to the needle of a hypodermal syringe after having inserted said cannula into a hollow shaft S of said needle N. After transferring (S2) beams of an input light emitted by a light source LS from a proximal end exterior of said patient's body on which said input light is incident to a distal end located within a tissue region of interest (ROI) around the tip of needle N by means of a first light guiding means LGMl inserted into the hollow shaft S of said needle, thereby providing an output light assignable to the intensity of the input light for illuminating said tissue region, and - by using a second light guiding means LGM2 inserted into the hollow shaft S - guiding (S3) the back-scattered light reflected from a tissue lying in the navigation path of said needle to a light detector LD located at a proximal end of said second light guiding means LGM2, the intensity of the back-scattered light is measured (S4) by means of said light detector. According to this method, it is thereby optionally foreseen to generate (S5), if necessary, a warning signal for indicating when needle N is approaching an intervening anatomical structure BV to be left unscathed and/or when the tip of said needle has reached a pathological tissue anomaly to be excised. In case of no warning signal, said needle is further advanced (S6) in the direction towards said tissue region of interest (ROI) such that detected pathological tissue anomalies can be excised (S6') and taken as a biopt by means of said needle.

APPLICATIONS OF THE INVENTION

The present invention and the above-described exemplary embodiments may be used in the field of surgical and minimally invasive interventions as required for percutaneous needle biopsies carried out under X-ray, CT, MR, sonography or hybrid radiography/MR imaging, in particular in the scope of image-guided brain biopsies, brain ablations or brain neurostimulations.

While the present invention has been illustrated and described in detail in the drawings and in the foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive, which means that the invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure and the appended claims. In the claims, the word ,,comprising" does not exclude other elements or steps, and the indefinite article ,,a" or ,,an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures can not be used to advantage. Any reference signs contained in the claims should not be construed as limiting the scope of the invention.

Table of used reference signs and their meanings

AS alarm system

B bladder

BV blood vessel

CA liquid guiding cannula (optional)

CCD charge-coupled device

CL collection lens

CN connector

CO operator console

CTR controller

DA detector array comprising a number of photosensors

DE distal end

DL dielectric layer

FL focusing lens

FOP side firing fiberoptic probe

FT flexible tubing

H handle

Hb deoxygenated hemoglobin

HbO₂ oxygenated hemoglobin

HW hook wire (optional)

IR infrared spectral range

LA LED array

LD light detector

LGMi illumination optical fiber

LGM₂ detector optical fiber

LS light source

ML_g mirror layer underneath dielectric layer DL

ML1-ML5 mirror layers above dielectric layer DL

N surgical or biopsy needle

NG needle guide

NIR near-infrared spectral range

NS needle shank

O sample object OSP optical spectrometer

P prostate

RA receive antenna

ROI tissue region of interest

S needle shaft

SH sample holder

SK surgical knife

SP loudspeaker

SPG spectrograph

TA transmit antenna

TL threshold level

UP ultrasound probe

UV ultraviolet spectral range

VG voltage generator

Vis visible spectral range

W window

WR wireless receiver

WS workstation

WT wireless transmitter

Claims

CLAIMS:

1. A surgical or biopsy needle (N) for being percutaneously introduced into tissue of a patient, said needle comprising a hollow shaft (S) longitudinally extending within the interior of the needle (N) with at least one first inserted light guiding means (LGMl) for transferring beams of an input light emitted by a light source (LS) from a proximal end on which said input light is incident to a distal end located within a tissue region of interest (ROI) around the tip of said needle (N), thereby providing an output light assignable to the intensity of the input light for illuminating said tissue region, and at least one second inserted light guiding means (LGM2) for guiding the back-scattered light reflected from the tissue region of interest (ROI) to a light detector (LD) located at a proximal end of said at least one second inserted light guiding means (LGM2), wherein said light detector (LD) has an output interface connected to an alarm system (AS) which, if necessary, generates a warning signal for indicating when the needle (N) is approaching an intervening anatomical structure (BV) lying in the navigation path of said needle that must be left unscathed and/or when the tip of the needle (N) has reached a pathological tissue anomaly to be excised.

2. The surgical or biopsy needle (N) according to claim 1, wherein said light source (LS) is a battery-operated light emitting diode or a battery-operated semiconductor laser integrated in the interior of said hollow shaft (S) and optically coupled to the proximal end of said at least one first inserted light guiding means (LGMl).

3. The surgical or biopsy needle (N) according to claim 1, wherein said light source (LS) is an incandescent light bulb, a high-intensity discharge lamp, a light emitting diode or semiconductor laser located exterior to said patient's body and optically coupled to the proximal end of said at least one first inserted light guiding means (LGMl).

4. The surgical or biopsy needle (N) according to claim 1, wherein said light detector (LD) is a battery-operated photosensor integrated in the interior of said hollow shaft (S) and optically coupled to the proximal end of said at least one second inserted light guiding means (LGM2).

5. The surgical or biopsy needle (N) according to claim 1, wherein said light detector (LD) is a photosensor located exterior to said patient's body and optically coupled to the proximal end of said at least one second inserted light guiding means (LGM2).

6. The surgical or biopsy needle (N) according to claim 1, wherein said first at least one light guiding means (LGMl) and said second at least one light guiding means (LGM2) are each realized as an optical fiber.

7. The surgical or biopsy needle (N) according to claim 1, wherein the alarm system (AS) is integrated in the interior of said hollow shaft (S) at the proximal end of said needle (N) and electrically connected to said light detector (LD).

8. The surgical or biopsy needle (N) according to claim 1, wherein the alarm system (AS) is located exterior to said patient's body and wirelessly coupled to a wireless transmitter (WT) integrated in the interior of said hollow shaft (S) at the proximal end of said needle (N) which serves for providing said alarm system (AS) with the output signal of the light detector (LD) over the air interface.

9. The surgical or biopsy needle (N) according to claim 1, wherein the warning signal is an optical signal generated by a single monochromatic light emitting diode or by an integrated LED array (LA) of said alarm system (AS), said LED array comprising a number of monochromatic light emitting diodes each being capable of emitting light waves in a different band of the visible spectrum of light and thus producing light beams of a different color and/or intensity indicative of the distance between said needle (N) and an intervening anatomical structure (BV) to be left unscathed lying in the navigation path in front of said needle when advancing the needle in a direction towards the tissue region of interest (ROI).

10. The surgical or biopsy needle (N) according to claim 1, wherein the warning signal is an acoustic signal generated by an integrated loudspeaker (SP) of said alarm system (AS) whose frequency and/or loudness is indicative of the distance between said needle (N) and an intervening anatomical structure (BV) to be left unscathed lying in the navigation path in front of said needle when advancing the needle in a direction towards the tissue region of interest (ROI).

11. The surgical or biopsy needle (N) according to claim 9, wherein said alarm system is configured to vary the color or intensity of the optical signal and/or the switching frequency of an on-off keying sequence modulating the optical signal which encodes the information to be conveyed by this signal depending on the intensity of the back-scattered light waves reflected from the intervening anatomical structure (BV) lying in the navigation path in front of said needle such that a surgeon is warned not to further advance said needle in the direction towards the intervening anatomical structure.

12. The surgical or biopsy needle (N) according to claim 9, wherein said alarm system is configured to vary the color or intensity of the optical signal and/or the switching frequency of an on-off keying sequence modulating the optical signal which encodes the information to be conveyed by this signal depending on the intensity of the back-scattered light waves reflected from the tissue region of interest (ROI) to be excised lying in the navigation path in front of said needle such that a surgeon is guided to further advance said needle in the direction towards this tissue region.

13. The surgical or biopsy needle (N) according to claim 10, wherein said alarm system (AS) is configured to vary the frequency or loudness of the acoustic signal and/or the switching frequency of an on-off keying sequence modulating the acoustic signal which encodes the information to be conveyed by this signal depending on the intensity of the back-scattered light waves reflected from the intervening anatomical structure (BV) lying in the navigation path in front of said needle (N) such that a surgeon is warned not to further advance said needle in the direction towards the intervening anatomical structure.

14. A method for percutaneously introducing a surgical or biopsy needle (N) into tissue of a patient, said method comprising the steps of transferring (S2) beams of an input light emitted by a light source (LS) from a proximal end exterior of said patient's body on which said input light is incident to a distal end located within a tissue region of interest (ROI) around the tip of said needle (N) by means of a first light guiding means (LGMl) inserted into a hollow shaft (S) of said needle, thereby providing an output light assignable to the intensity of the input light for illuminating said tissue region, by using a second light guiding means (LGM2) inserted into the hollow shaft (S), guiding (S3) the back-scattered light reflected from a tissue lying in the navigation path of said needle to a light detector (LD) located at a proximal end of said second light guiding means (LGM2), measuring (S4) the intensity of the back-scattered light by means of said light detector (LD) and, if necessary, generating (S5) a warning signal for indicating when the needle

(N) is approaching an intervening anatomical structure (BV) to be left unscathed and/or when the tip of the needle (N) has reached a pathological tissue anomaly to be excised.

15. A method according to claim 14, additionally comprising the step of guiding (S 1) a liquid given by a targeted contrast agent or dye fluorescent in the visible spectrum of light to the tip of said needle (N) via a cannula (CA) with a substantially tubular wall and an internal lumen having an open distal end similar to the needle of a hypodermal syringe, said cannula (CA) being inserted into the hollow shaft (S) of said needle (N).