CN101234024A - Scanning method of computer tomography - Google Patents
Scanning method of computer tomography Download PDFInfo
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- CN101234024A CN101234024A CNA2007100631704A CN200710063170A CN101234024A CN 101234024 A CN101234024 A CN 101234024A CN A2007100631704 A CNA2007100631704 A CN A2007100631704A CN 200710063170 A CN200710063170 A CN 200710063170A CN 101234024 A CN101234024 A CN 101234024A
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Abstract
The invention discloses a scanning method for computerized tomography (CT) which comprises a data acquisition period and a non-data acquisition period. In the data acquisition period, an X-ray tube circles round a patient and obtains the data of the patient; in the non-data acquisition period, an examination couch is moved from a scanning position to the next scanning position; wherein, in the data acquisition period, the angle of rotation of the X-ray tube is less than 360 degrees when obtaining the data of the patient, and in the non-data acquisition period, the examination couch moves immediately from the scanning position after the X-ray tube is shut. Compared with the complete scan mode and the partial scan mode in prior art, the scanning method of the invention shortens the examination time when a patient lies in an examination couch, thus improving the diagnostic efficiency in hospitals.
Description
Technical field
The present invention relates to a kind of scan method method, particularly relate to a kind of computer tomography (Computed Tomography; Abbreviate " CT " as) scan method.
Background technology
The computer tomography CT scan is divided into sequence scanning (Sequence Scan) and helical scanning (Spiral Scan).Sequence scanning also claims single sweep operation, is a kind of scan mode based on progress-collection (step-and-shoot) pattern.The sequence scanning mode comprises data acquisition cycle and non-data acquisition cycle.In data acquisition cycle, patient's transfixion, and X-ray tube and detector rotate around patient with certain speed; After a complete data set of this section was obtained, non-data acquisition cycle began.X-ray tube is closed, and patient then moves to the position of next scanning.
For typical C T equipment, because mechanical system and patient's restriction, minimum non-data acquisition cycle is on several seconds magnitude.The restriction of mechanical system mainly is the restriction that causes owing to general patient body weight, and examinating couch needs certain hour that the patient with certain body weight is moved on to next position from a position.Patient's restriction is because immobilized patient is moved a segment distance, at first needs patient is accelerated to certain speed, near the target location time it is slowed down then.Because adjacent scan slice is at interval generally at several millimeters, needed acceleration of patient and deceleration are all quite big, and human body and non-rigid (internal can move or be out of shape), any acceleration or deceleration can cause that all patient is intravital mobile.Therefore, must consume the regular hour makes correction of motion artefacts reach minimum.
Normal sequence scanning uses the once complete rotation (i.e. 360 degree) of X-ray tube as data acquisition cycle.In addition, also has a kind of part scanning (Partial Scan) in the sequence scanning.In the part scanning in the data acquisition cycle anglec of rotation of X-ray tube less than 360 degree.
Duty cycle in the sequence scanning (ratio of data acquisition cycle and whole sweep time) is approximately 50% even be lower than 50%.For improving duty cycle, helical scan mode is suggested.Spiral CT continuously obtains data for projection when patient is with the constant speed translation.Although patient can move with the speed that changes in theory, in order to simplify, the mode that nearly all commercial CT manufacturer has all adopted constant speed to move.Because patient does not have the acceleration, deceleration degree in the scanning process, non-data acquisition cycle is just removed fully.So just obtained almost 100% duty cycle.On the frame some the path with respect to fixing point on one's body the patient be helix, so this scan mode is called as spiral CT.
The ability that all possesses sequence scanning and helical scanning in the present CT machine simultaneously.Although the duty cycle less than 100% of sequence scanning, for the disease of some particular type, application sequence scanning is diagnosed and is absolutely necessary.Then there is the possibility of further shortening the time that application sequence scanning is checked patient.
Summary of the invention
Therefore, main purpose of the present invention is to provide a kind of scan method of computer tomography, makes this method of application can further shorten the review time of patient on examinating couch, thereby has accelerated the diagnosis efficiency of hospital.
For achieving the above object, the invention provides a kind of scan method of computer tomography, comprise a data acquisition cycle and a non-data acquisition cycle, center on patient's rotation and obtain described patient data at described data acquisition cycle one X-ray tube, move to next scanning position at described non-data acquisition cycle one examinating couch from the one scan position, wherein, the anglec of rotation that described X-ray tube obtains described patient data in described data acquisition cycle is less than 360 degree, and described examinating couch moved from described scanning position at once after described X-ray tube was closed in described non-data acquisition cycle.
According to an aspect of the present invention, described X-ray tube obtains described patient data's the anglec of rotation less than 360 degree and greater than 180 degree.
According to another aspect of the present invention, the anglec of rotation of obtaining described patient data according to described X-ray tube is carried out the image reconstruction of described computer tomography.
According to a further aspect of the invention, the traveling time of described examinating couch equals described X-ray tube and revolves the three-sixth turn required time and deduct the angle required time that described patient data is obtained in the rotation of described X-ray tube.
The scan method of computer tomography provided by the present invention, the rotation of X-ray tube is less than 360 degree in its sweep time t3, and t3 begins examinating couch mobile phase t2 after finishing immediately in sweep time, therefore compare with complete scan mode of the prior art, part scan mode, the inventive method has shortened the review time of patient on examinating couch, thereby has accelerated the diagnosis efficiency of hospital.
Description of drawings
Below in conjunction with accompanying drawing the specific embodiment of the present invention is described in further detail, wherein:
Fig. 1 is the complete scan mode sketch map of sequence scanning in the prior art.
Fig. 2 is the part scan mode sketch map of sequence scanning in the prior art.
Fig. 3 is the rapid scanning mode sketch map of the sequence scanning among the present invention.
The specific embodiment
For ease of the rapid scanning mode of sequence scanning among explanation the present invention, the complete scan mode and the part scan mode of sequence scanning illustrated the present invention in the contrast prior art below.
Fig. 1 is the complete scan mode sketch map of sequence scanning in the prior art.The complete scan mode of sequence scanning is divided into three phases among Fig. 1, is respectively scanning preparatory stage t0, sequence scanning stage t1, examinating couch mobile phase t2.
At scanning preparatory stage t0, operator at first will position the patient on the CT examination bed, do one-time positioning scanning.The purpose of location scanning is to determine patient's anatomic landmarks, with the exact position and the scope of decision CT sequence scanning or helical scanning.As under the scan pattern, it is static that X-ray tube and patient keep in the location, and examinating couch is at the uniform velocity mobile.After the location was as sweep start, the operation Control Computer was sent instruction at once, made frame rotate to the assigned address of operator's regulation.Computer sends instructions to examinating couch, X ray generation systems, X ray detection system and image generation system then, carries out single pass.After examinating couch arrives scanning starting position, in whole scanning process, keep constant speed.High tension generator meet the requirements of rapidly voltage and sweep time the chien shih X-ray tube voltage and current remain on the level of predesignating.X-ray tube produces the X ray line, and X-ray is measured by X-ray detector, generates the signal of telecommunication.Data-acquisition system is analog signal conversion a digital signal with the output of uniform sampling rate collection detector simultaneously.The data of Cai Jiing are sent to image generation system (system that for example comprises high-speed computer and digital signal processing chip) processing then.The data obtained are through after pretreatment and strengthening, and are sent to display device and watch with data storage device for operator and filing.
After accurately location and sweep limits (based on the location scanning image) were determined, operator were based on scheme of formulating or the new scheme predetermined C T scan instruction of formulating in the past.Sweeping scheme will be determined collimator aperture, detector aperture, X-ray tube voltage and current, scan pattern, examinating couch position, gantry motion speed, rebuild the visual field (FOV), convolution kernel and other many parameters.According to selected sweeping scheme, the operation Control Computer will be sent a series of orders and give frame, examinating couch, X ray generation systems, X ray detection system and image generation system according to the similar described mode of location scanning of doing.Begin to enter sequence scanning stage t1 this moment.
In sequence scanning stage t1, the once complete rotation of X-ray tube (i.e. 360 degree) is a data acquisition cycle.In this data acquisition cycle, patient's transfixion, and the X-ray tube, high tension generator, the detector that are positioned on the frame rotate around patient with certain speed.Finish the complete scan of one time 360 degree when X-ray tube after, this patient has just been carried out a complete data set obtained.Non-subsequently data acquisition cycle begins, and promptly enters examinating couch mobile phase t2.In the t2 stage, X-ray tube is closed, and examinating couch is moved into next scanning position.
Subsequently, restart sequence scanning stage t1, X-ray tube carries out the scanning of 360 degree once more to obtain data.At the t1 sweep phase patient having been carried out for the second time complete data set obtains.After the t1 stage finished, X-ray tube was closed, and began to enter non-data acquisition cycle, and the examinating couch traveling time is t2.And then beginning data acquisition phase.Said process is recycled to the end of scan to patient always.
Fig. 2 is the part scan mode sketch map of sequence scanning in the prior art.Part scan mode among Fig. 2 comprises four-stage, is respectively that scanning preparatory stage t0, sequence scanning stage t3, frame rotate to 360 and spend stage t4, examinating couch mobile phase t2.
Operation in the scanning operation carried out of preparatory stage t0 and complete scan mode shown in Figure 1 is basic identical, repeats no more herein.After accurate location of t0 stage and sweep limits (based on the location scanning image) were determined, operator began to enter sequence scanning stage t3 then based on the scheme predetermined C T scan instruction of scheme of formulating or new formulation in the past.
According to the image reconstruction theory, only need the X-ray tube anglec of rotation to be not less than 180 degree when carrying out image reconstruction and can reconstruct last image.Therefore in sequence scanning stage t3, the anglec of rotation of X-ray tube usually greater than 180 degree less than 360 degree, compare with t1 sweep time among Fig. 1 like this, part scanning will shorten to t3 sweep time.That is to say that t3 is the data acquisition cycle in the part scanning.In this data acquisition cycle, patient's transfixion, and the X-ray tube, high tension generator, the detector that are positioned on the frame rotate around patient with certain speed.
After X-ray tube is finished once part scanning, this patient has just been carried out a data set obtained.Non-subsequently data acquisition cycle begins, and this stage X-ray tube is closed.Non-data acquisition cycle comprises that frame rotates to 360 and spends stage t4 and examinating couch mobile phase t2.Because therefore the anglec of rotation of X-ray tube continues to rotate to 360 degree that scan beginning from this X-ray tube at equipment such as t4 stage frame drive X-ray tube less than 360 degree among the part sweep phase t3.Subsequently, enter examinating couch mobile phase t2.In the t2 stage, X-ray tube is still closed, and examinating couch is moved into next scanning position.From sequence scanning stage t3, rotate to through frame 360 spend stage t4, the process in examinating couch mobile phase t2 stage is recycled to the end of scan to patient always.
Fig. 3 is the rapid scanning mode sketch map of the sequence scanning among the present invention.Rapid scanning mode of the present invention comprises three phases, is respectively scanning preparatory stage t0, sequence scanning stage t3, examinating couch mobile phase t2.
Operation in the scanning operation carried out of preparatory stage t0 and complete scan mode shown in Figure 1 is basic identical, repeats no more herein.After accurate location of t0 stage and sweep limits (based on the location scanning image) were determined, operator began to enter sequence scanning stage t3 then based on the scheme predetermined C T scan instruction of scheme of formulating or new formulation in the past.
Sweep phase t3 in the rapid scanning mode of the present invention is identical with sweep phase t3 in the part scan mode shown in Figure 2.That is to say that in sequence scanning of the present invention stage t3, the anglec of rotation of X-ray tube, is promptly compared complete scan mode shown in Figure 1 and shortened sweep time less than 360 degree greater than 180 degree usually.T3 is the data acquisition cycle in the rapid scanning of the present invention.In this data acquisition cycle, patient's transfixion, and the X-ray tube, high tension generator, the detector that are positioned on the frame rotate around patient with certain speed.
After X-ray tube is finished less than 360 scannings of spending, this patient has just been finished a data set obtained.Non-subsequently data acquisition cycle begins, and closes at non-data acquisition cycle X-ray tube, and examinating couch is moved into next scanning position, and traveling time is t2.Above-mentioned from sweep phase t3, the process in process examinating couch mobile phase t2 stage is recycled to the end of scan to patient always.
Because the anglec of rotation of X-ray tube less than 360 degree, can reconstruct required image according to the image reconstruction theory greater than 180 degree.But in image reconstruction process, also need angle parameter required in the image reconstruction process to be set according to the anglec of rotation of X-ray tube.
In addition, if wish that for the ease of image reconstruction X-ray tube all scans from patient's same orientation in each cycle, then the traveling time of examinating couch equals X-ray tube and revolves the three-sixth turn required time and deduct the angle required time that described patient data is obtained in X-ray tube rotation.
By the contrast of above-mentioned three kinds of scan modes as seen, in scan method of the present invention, the rotation of X-ray tube is less than 360 degree in its sweep time t3, and t3 begins examinating couch mobile phase t2 after finishing immediately in sweep time, therefore compare with complete scan mode of the prior art, part scan mode, the inventive method has shortened the review time of patient on examinating couch, thereby has accelerated the diagnosis efficiency of hospital.
Claims (4)
1. the scan method of a computer tomography, comprise a data acquisition cycle and a non-data acquisition cycle, an X-ray tube centers on patient's rotation and obtains described patient data in described data acquisition cycle, an examinating couch moves to next scanning position from the one scan position in described non-data acquisition cycle, it is characterized in that, the anglec of rotation that described X-ray tube obtains described patient data in described data acquisition cycle is less than 360 degree, and described examinating couch moved from described scanning position at once after described X-ray tube was closed in described non-data acquisition cycle.
2. the scan method of a kind of computer tomography according to claim 1 is characterized in that: described X-ray tube obtains described patient data's the anglec of rotation less than 360 degree and greater than 180 degree.
3. the scan method of a kind of computer tomography according to claim 1 and 2 is characterized in that: the anglec of rotation of obtaining described patient data according to described X-ray tube is carried out the image reconstruction of described computer tomography.
4. the scan method of a kind of computer tomography according to claim 1 and 2 is characterized in that: the traveling time of described examinating couch equals described X-ray tube and revolves the three-sixth turn required time and deduct the angle required time that described patient data is obtained in described X-ray tube rotation.
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| CNA2007100631704A CN101234024A (en) | 2007-01-30 | 2007-01-30 | Scanning method of computer tomography |
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| CNA2007100631704A CN101234024A (en) | 2007-01-30 | 2007-01-30 | Scanning method of computer tomography |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102988069A (en) * | 2011-09-14 | 2013-03-27 | 上海西门子医疗器械有限公司 | Device and method for carrying out pre-setting on scanning based on positioning image |
| CN103800027A (en) * | 2012-11-14 | 2014-05-21 | 上海联影医疗科技有限公司 | Positron emission computed tomography scanning method and system |
| CN103890609A (en) * | 2012-05-09 | 2014-06-25 | 株式会社东芝 | Method for estimating number of random coincidences and device for estimating number of random coincidences |
| CN104337535A (en) * | 2013-08-02 | 2015-02-11 | 上海联影医疗科技有限公司 | Computed tomography method and device |
| CN105433971A (en) * | 2014-07-29 | 2016-03-30 | 上海西门子医疗器械有限公司 | Computed tomography method and device |
-
2007
- 2007-01-30 CN CNA2007100631704A patent/CN101234024A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102988069A (en) * | 2011-09-14 | 2013-03-27 | 上海西门子医疗器械有限公司 | Device and method for carrying out pre-setting on scanning based on positioning image |
| CN103890609A (en) * | 2012-05-09 | 2014-06-25 | 株式会社东芝 | Method for estimating number of random coincidences and device for estimating number of random coincidences |
| CN103890609B (en) * | 2012-05-09 | 2016-03-23 | 株式会社东芝 | Accidentally count presuming method simultaneously and accidentally count estimating device simultaneously |
| CN103800027A (en) * | 2012-11-14 | 2014-05-21 | 上海联影医疗科技有限公司 | Positron emission computed tomography scanning method and system |
| CN104337535A (en) * | 2013-08-02 | 2015-02-11 | 上海联影医疗科技有限公司 | Computed tomography method and device |
| CN105433971A (en) * | 2014-07-29 | 2016-03-30 | 上海西门子医疗器械有限公司 | Computed tomography method and device |
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Open date: 20080806 |