CN206696439U - A kind of detector for the distribution scanning of small field size dosage - Google Patents
A kind of detector for the distribution scanning of small field size dosage Download PDFInfo
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- CN206696439U CN206696439U CN201720388190.8U CN201720388190U CN206696439U CN 206696439 U CN206696439 U CN 206696439U CN 201720388190 U CN201720388190 U CN 201720388190U CN 206696439 U CN206696439 U CN 206696439U
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- detector
- sleeve
- field size
- small field
- chamber
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Abstract
The utility model discloses a kind of detector for the distribution scanning of small field size dosage, including being tightly connected the air tight housing formed by sleeve, balance cap and caudal peduncle, the sleeve includes preceding narrow diameter section point and posterior wide diameter part point, the caudal peduncle is located at the tail end of the wide diameter part point, and forms rear chamber with the wide diameter part point of the sleeve；The balance cap is located at the top of the narrow diameter section point, and forms ionisation chamber with the narrow diameter section point of the sleeve, and the ionisation chamber internal diameter is 1.5 2mm, and the sensitive volume of air of the ionisation chamber is 0.1 0.2cm3.Panel detector structure of the present utility model is simple, small volume, is easy to seal, it is ensured that good sealing, and it is small to leak electricity, energy response is good, and scanning resolution is high during use, can accurate detector amount key index.
Description
Technical field
Radiation therapy technology field is the utility model is related to, is distributed scanning for small field size dosage more particularly to a kind of
Detector.
Background technology
One of the advanced therapeutic modality of IMRT (IMRT) technology as accurate treatment tumour, can give tumour
The accurate dosage in target area and the growth of tumour can be efficiently controlled.One of property unique IMRT is exactly that tumor target is split
Beam irradiation is carried out out into multiple small launched fields, and modulates the uneven radiation profile of intensity, it is high so as to obtain more conformal target area
Dosage is distributed.Therefore, the degree of accuracy of the small field size dosage of radiotherapy is shouldered heavy responsibilities, and the emphasis of radiotherapy circle concern.
Quality control is needed in radiotherapy implementation process, in the multinomial important indicator for examining medical accelerator performance,
The measurement of radiation field size flatteness and symmetry is mainly carried out using scanning survey water tank.Domestic outer water tank measurement dosage is adopted at present
Scanning dose detector is mostly 0.6cm3Cavity ionization chamber, particularly scan ionisation chamber it is right under the driving of stepper motor
Each point in water tank is scanned, and dose of radiation is converted into current signal, by measuring the change of radiation dose rate come to spoke
Close rate is penetrated to be modified.Cavity ionization chamber is a kind of ionization using gas in sensitive volume come radiation beam absorbed dose of radiation
Detector, structure comparatively robust measures easy to use in water mould, and measurement advantage is it is obvious that its high sensitivity, measurement are accurate
Degree is high, signal to noise ratio height etc., but the short slab during the use of the larger always scanning water tank of sensitive volume, and this is required
0.6cm3Cavity ionization chamber be applied to a diameter of 4cm and the dose point of the above and the measurement of big field dose.
But the main advantage of the new technology of radiotherapy at present is exactly small wild separation, that is, it is wide in clinical medium and small irradiation field application
It is general, the plane dosage distribution problem of particularly small launched field, it is necessary to develop the detector of the small launched field of coincidence measurement, obtain more
The dose value to tally with the actual situation.
Show according to correlative study, thermoluminescent dosimeter (TLD) can be used for determining the small wild absorbent of IMRT multi-diaphragm collimators
Amount, but its is non-watertight, and can only measure a dose point every time, and scene can only measure and once can not repeat at the scene
Utilize, which limits its application prospect as small launched field scan detector.Needle point ionisation chamber sensitive volume is 0.015cm3,
Can the small wild absorbed dose of radiation of accurate measurement, but sensitive volume is too small, and the scanning larger i.e. signal to noise ratio of fluctuation signal that gets up is small, and survey
The dosage magnitude tracing complexity of amount should not be popularized, and also limit its application as scan detector.
As can be seen here, the detector of the above-mentioned existing small launched field of measurement is upper with using in structure, it is clear that has still suffered from inconvenience
With defect, and urgently it is further improved.
Utility model content
The purpose of this utility model is to provide a kind of detector for the distribution scanning of small field size dosage, makes its structure simple
It is single, small volume, it is easy to seal, it is ensured that good sealing, and it is small to leak electricity, energy response is good, and scanning resolution is high during use,
Can accurate detector amount key index.
To achieve the above object, the utility model adopts the following technical scheme that：
A kind of detector for the distribution scanning of small field size dosage, including shape is tightly connected by sleeve, balance cap and caudal peduncle
Into air tight housing, the sleeve includes preceding narrow diameter section point and posterior wide diameter part point, and the caudal peduncle is located at the wide footpath
Partial tail end, and form rear chamber with the wide diameter part point of the sleeve；The balance cap is located at the top of the narrow diameter section point,
And point forming ionisation chamber with the narrow diameter section of the sleeve, the ionisation chamber internal diameter is 1.5-2mm, the sensitive air of the ionisation chamber
Volume is 0.1-0.2cm3。
As a further improvement, the ionisation chamber inside radius is 1.7mm.
Sensitive volume of air in the ionisation chamber is 0.16cm3。
Rear chamber's maximum inner diameter 10mm.
The overall length 40-45mm of the air tight housing.
High-pressure stage and pickup electrode are provided with the ionisation chamber, the high-pressure stage is arranged on the inwall of ionisation chamber, the letter
Number pole is arranged on the center of ionisation chamber；High-pressure stage connector and pickup electrode connection terminal, the high pressure are provided with the rear chamber
Pole connector is arranged in back cavity chamber interior walls, and is connected with the high-pressure stage, and the pickup electrode connection terminal is arranged on back cavity
Room center, and be connected with the pickup electrode, the high-pressure stage connector before pickup electrode connection terminal with being also filled with insulating
Body.
The rear end of the insulator is provided with friction top, and the friction top rear is provided with matching clamping pad, the tail
Handle is close to the rear of the clamping pad.
The high-pressure stage is using the graphite sleeve being close in the ionization chamber interior walls, the signal extremely aluminium pole.
Pass through adhering and sealing between the sleeve, balance cap and caudal peduncle.
The sleeve, balance cap and caudal peduncle are made of PMMA materials.
Due at least there is advantages below using above-mentioned technical proposal, the utility model：
(1) detector of the present utility model for the distribution scanning of small field size dosage, simple in construction, small volume, is easy to close
Envelope, it is ensured that good sealing, the ionisation chamber internal diameter are 1.5-2mm, and the sensitive volume of air of the ionisation chamber is 0.1-
0.2cm3, electric leakage is small, and energy response is good, and scanning resolution is high during use, can accurate detector amount key index.
(2) the ionisation chamber inside radius 1.7mm, the ionization chamber radius than using now are small 1.3mm, effectively improve resolution
Rate, scanning resolution can be improved when for scanning 5cmX5cm launched fields.
(3) the sensitive volume of air of ionisation chamber is 0.16cm3, ionisation chamber probe sensitive volume is small, and energy response is good, can
The small wild absorbed dose of radiation of accurate measurement, and fluctuation signal is smaller during scanning, positional precision is high.
(4) sleeve, balance cap and caudal peduncle are bonded mutually, are not used screw thread as connected mode, are effectively reduced overall chi
It is very little, make detector more compact.
(5) sleeve, balance cap and caudal peduncle for being used to be formed air tight housing are made of PMMA materials, are easy to be bonded, and
Water resistance is good, and water resistance is better than the heat-shrink tube that original detector uses.
(6) detector of the present utility model for the distribution scanning of small field size dosage, has a wide range of application, is adapted to medical portion
Door, scientific research institution carry out radiotherapy quality control efforts.
Brief description of the drawings
Above-mentioned is only the general introduction of technical solutions of the utility model, in order to better understand technology hand of the present utility model
Section, below in conjunction with accompanying drawing, the utility model is described in further detail with embodiment.
Fig. 1 is the panel detector structure cut-away view of the present utility model for the distribution scanning of small field size dosage.
Fig. 2 is the measurement collection of illustrative plates obtained using the detector of the present utility model for the distribution scanning of small field size dosage.
In Fig. 1：1：Caudal peduncle, 2：Clamping pad, 3：Friction top, 4：Sleeve, 5：Insulator, 6：Graphite sleeve, 7：Balance cap, 8：
High-pressure stage connector, 9：Signal connecting terminal, 10：Pickup electrode.
Embodiment
The utility model is for the deficiency in the small launched field scanning dose measurement of existing radiotherapy, there is provided one kind is used for small launched field
The detector of dosage distribution scanning.
Refer to shown in Fig. 1, the detector of the present utility model for the distribution scanning of small field size dosage, including air-tight cavity
Body, the air tight housing mainly by sleeve 4, the balance cap 7 installed in the front of sleeve 4 and the caudal peduncle 1 installed in the rear of sleeve 4 it
Between be sealed to form.It is preferred that mutual adhering and sealing between the sleeve 4, balance cap 7 and caudal peduncle 1, does not use screw thread as company
Mode is connect, effectively reduces overall dimension, makes detector more compact, specifically, the air tight housing is always about 40-45mm.
In addition, the sleeve 4, balance cap 7 and caudal peduncle 1 are made of PMMA materials, it is easy to be bonded, and water resistance is good, water proofing property
Can be better than the heat-shrink tube that original detector uses.
As shown in fig. 1, the sleeve 4 includes preceding narrow diameter section point and posterior to panel detector structure of the present utility model
Wide diameter part point, the balance cap 7 are located at the top of the narrow diameter section point, and form ionisation chamber therewith；The caudal peduncle 1 is located at described
The tail end of wide diameter part point, and rear chamber is formed therewith.
High-pressure stage 6 and pickup electrode 10 are provided with the ionisation chamber, wherein, described in the high-pressure stage 6 is arranged to be close to
The sleeve-shaped in chamber interior walls is ionized, the material of high-pressure stage 6 uses graphite, forms overall graphite sleeve.The signal extremely aluminium pole,
It is arranged on the center of ionisation chamber.
High-pressure stage connector 8 and pickup electrode connection terminal 9 are provided with the rear chamber, wherein, the high-pressure stage connector 8
It is arranged in back cavity chamber interior walls, and is connected with the high-pressure stage 6, the pickup electrode connection terminal 9 is arranged on rear chamber center,
And it is connected with the pickup electrode 10.In use, pickup electrode terminal 9 is connected by coaxial cable, TNC coaxial fittings and electrometer
Connect.
In addition, being also filled with insulator 5 in the rear chamber, the insulator 5 is located at the high-pressure stage connector 8 and letter
Between number pole connection terminal 8, the rear end face of the insulator 5 is provided with friction top 3, and the rear of friction top 3 is provided with therewith
The clamping pad 2 matched somebody with somebody, the caudal peduncle 1 are close to the rear of the clamping pad 1.
In said structure, it is 1.5-2mm to set the ionisation chamber internal diameter, and the sensitive volume of air of the ionisation chamber is 0.1-
0.2cm3.Implement example as preferable, the ionisation chamber inside radius inside radius of graphite sleeve 6 (namely in figure) is 1.7mm,
Sensitive volume of air in the ionisation chamber is 0.16cm3, rear chamber's maximum inner diameter 10mm, the cavity ionization chamber it is total
Long 42.6mm.The ionisation chamber sensitive volume is small, and electric leakage is small, and energy response is good, can the small wild absorbed dose of radiation of accurate measurement, and sweep
Fluctuation signal is smaller when retouching, and positional precision is high, and scanning resolution can be improved when for scanning 5cmX5cm launched fields.
As a result of above technical scheme, the detector of the present utility model for the distribution scanning of small field size dosage, knot
Structure is simple, easy to use efficient, is easy to seal, it is ensured that good sealing, and sensitive volume of popping one's head in is small, positional precision is high,
Leak electricity small, energy response is good.Showing by testing detection, the utility model detector can meet the requirement of Radiotherapy dosimetry measurement,
Simultaneously suitable for X, gamma-ray dosage measurement, and measure accurately.Scanning point can be improved when for scanning 5cmX5cm launched fields
Resolution, improve the accuracy of Dose distribution data.
It is the concrete outcome that part Experiment test is carried out using detector of the present utility model below：
1st, dosage measurement repeatability
Dosage measurement repeatability is under identical measuring condition, and continuous several times measurement gained is carried out to same measured object
As a result the uniformity between.Record the measured value of detector when irradiating every time and assess its repeatability error size, using change
Different coefficient characterizes.
The coefficient of variation is identified below by formula (1)：
In formula：Ri- ith dosage measurement value；
- n times dosage measurement value average value；
N-pendulous frequency, n 6.
Under medical accelerator 6MV X ray, ource-skin Distance 100cm, launched field is 10cm × 10cm, close rate 300MU/
Min, effective measurement point position of detector is at the centers such as launched field.Data record such as table 1.
The detector repetition measurement unit of table 1：Gy
The dosage measurement repeatability of ionisation chamber is calculated according to the data of table 1 and formula (1)<0.4%.
2nd, dose response is linear
The dose response of detector is linearly relevant with measurement accuracy.Actual conditions and pendulum position are same as above, medical accelerator 6,
Under 10MV X ray, go out beam 50MU, 100MU, 200MU and 400MU and measure, record such as table 2.60Under Co γ photon lines, source
Skin is divided into 10s, 20s, 40s, 80s, record such as table 3 away from SSD=50cm, launched field FS=10cm × 10cm, setting measurement time.
The linear measurement unit of ionisation chamber under the different-energy X-ray of table 2：Gy
Table 360The linear measurement unit of ionisation chamber under Co γ light：Gy
According to the data of table 2 and 3, line is entered with measured value to accelerator preset value MU or detector measurement time setting value
Property regression analysis, the deviation with theoretical value obtained by least square fitting curve and measured value is equal<0.5%.
3rd, dosage rate dependence
When dosemeter carries out dosage measurement under accelerator, certain essence should also be reached to Different Dose Rates dose response
Degree, to meet the requirement of actual plan checking.Actual conditions and pendulum position are same as above, in dosage under medical accelerator 6,10MV X ray
Rate is to be measured under 100MU/min, 200MU/min, 300MU/min, 400MU/min, 500MU/min and 600MU/min.Note
Record such as table 4.
Units of measurement under table 4 ionization chamber Different Dose Rates：Gy
Note：Maximum deviation=(Max-Min)/average value × 100%
By measured value record sheet 4 of the ionisation chamber under Different Dose Rates, maximum deviation=(Max-Min)/average value is defined
× 100%, then maximum deviation is 0.6%, is drawn under Different Dose Rates, dose response difference is smaller.
4th, the plane dose scan result of specific launched field
Ource-skin Distance is 100cm, and launched field is 5cm × 5cm, and the dose scan time is 60s, and using 6MVX rays, ionisation chamber has
Measurement point position is imitated at the centers such as launched field, measures the plane dosage of different depth.Record is as shown in Figure 2.
It is described above, only it is preferred embodiment of the present utility model, not the utility model is made any formal
Limitation, those skilled in the art make a little simple modification, equivalent variations or modification using the technology contents of the disclosure above,
Fall in the scope of protection of the utility model.
Claims (10)
1. a kind of detector for the distribution scanning of small field size dosage, it is characterised in that including close by sleeve, balance cap and caudal peduncle
The air tight housing that envelope connection is formed, the sleeve include preceding narrow diameter section point and posterior wide diameter part point, and the caudal peduncle is located at
The tail end of the wide diameter part point, and form rear chamber with the wide diameter part point of the sleeve；The balance cap is located at the narrow diameter section
Point top, and point form ionisation chamber with the narrow diameter section of the sleeve, the ionisation chamber internal diameter is 1.5-2mm, the ionisation chamber
Sensitive volume of air be 0.1-0.2cm3。
A kind of 2. detector for the distribution scanning of small field size dosage according to claim 1, it is characterised in that the electricity
It is 1.7mm from indoor radius.
A kind of 3. detector for the distribution scanning of small field size dosage according to claim 1, it is characterised in that the electricity
Sensitive volume of air from interior is 0.16cm3。
4. a kind of detector for the distribution scanning of small field size dosage according to claim 1, it is characterised in that after described
Chamber maximum inner diameter 10mm.
A kind of 5. detector for the distribution scanning of small field size dosage according to claim 1, it is characterised in that the gas
The overall length 40-45mm of close cavity.
A kind of 6. detector for the distribution scanning of small field size dosage according to claim 1, it is characterised in that the electricity
High-pressure stage and pickup electrode are provided with from interior, the high-pressure stage is arranged on the inwall of ionisation chamber, and the pickup electrode is arranged on ionization
The center of room；
High-pressure stage connector and pickup electrode connection terminal are provided with the rear chamber, the high-pressure stage connector is arranged on rear chamber
On inwall, and be connected with the high-pressure stage, the pickup electrode connection terminal be arranged on rear chamber center, and with the pickup electrode
It is connected, the high-pressure stage connector before pickup electrode connection terminal with being also filled with insulator.
7. a kind of detector for the distribution scanning of small field size dosage according to claim 6, it is characterised in that described exhausted
The rear end of edge body is provided with friction top, and the friction top rear is provided with matching clamping pad, and the caudal peduncle is close to the pressure
The rear tightly padded.
A kind of 8. detector for the distribution scanning of small field size dosage according to claim 6, it is characterised in that the height
Pressure pole is using the graphite sleeve being close in the ionization chamber interior walls, the signal extremely aluminium pole.
9. a kind of detector for the distribution scanning of small field size dosage according to claim any one of 1-8, the sleeve,
Pass through adhering and sealing between balance cap and caudal peduncle.
10. a kind of detector for the distribution scanning of small field size dosage according to claim any one of 1-8, its feature exist
In the sleeve, balance cap and caudal peduncle are made of PMMA materials.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201720388190.8U CN206696439U (en) | 2017-04-13 | 2017-04-13 | A kind of detector for the distribution scanning of small field size dosage |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110389372A (en) * | 2019-07-19 | 2019-10-29 | 广州瑞多思医疗科技有限公司 | A kind of launched field calculation method and system |
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- 2017-04-13 CN CN201720388190.8U patent/CN206696439U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110389372A (en) * | 2019-07-19 | 2019-10-29 | 广州瑞多思医疗科技有限公司 | A kind of launched field calculation method and system |
| CN110389372B (en) * | 2019-07-19 | 2022-10-21 | 广州瑞多思医疗科技有限公司 | Portal calculation method and system |
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Legal Events
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| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20171201 Termination date: 20180413 |