GB 16369-1996 Radiation protection standard for medical electron accelerators
Some standard content:
National Standard of the People's Republic of China
Radiological protection standard for usingof medical electron accelerator1 Subject content and scope of application
GB16369-1996
This standard specifies the requirements for radiological protection when medical electron accelerators (hereinafter referred to as accelerators) are used for human treatment. This standard applies to the production and use of accelerators with an energy below 50MeV. 2 Reference standards
GB4792 Basic standards for radiological protection
GB5294 Methods for monitoring individual doses of radiation workersGB9706.5 Special safety requirements for medical electron accelerators with energies of 1~50MeVGB15213 Performance and test methods of medical electron accelerators3 Technical requirements for accelerators
3.1 Technical requirements for radiation safety, electrical and mechanical safety of accelerators The technical requirements for radiation safety, electrical and mechanical safety and test methods of accelerators must comply with the relevant provisions of GB9706.5. 3.2 Requirements to prevent overdose
3.2.1 The control console must display the pre-selected values of irradiation parameters such as radiation type, nominal energy, irradiation time, absorbed dose, absorbed dose rate, treatment method, wedge filter type and specifications. 3.2.2 The start of irradiation must be interlocked with the pre-selected values of irradiation parameters displayed on the control console. Irradiation shall not be started before the control console selects various irradiation parameters.
3.2.3 Two independent dose monitoring systems must be equipped. Each dose monitoring system must be able to terminate irradiation independently. The failure of one dose monitoring system shall not affect the function of the other system. 3.2.4 The dose readings displayed by the two dose monitoring systems must remain unchanged after the irradiation is interrupted or terminated. After the irradiation is interrupted or terminated, the display must be reset to zero before the next irradiation can be started; if the irradiation is interrupted or terminated due to component or power failure, the reading display at the time of failure must be stored in a system and retained in a readable manner for at least 20 minutes. 3.2.5 When the two-channel dose monitoring system adopts a dual combination, when the absorbed dose reaches the preselected value, both systems must terminate the irradiation. 3.2.6 When the two-channel dose monitoring system is a primary/secondary combination, when the absorbed dose reaches the preselected value, the primary dose monitoring system must terminate the irradiation, and the secondary monitoring system must terminate the irradiation when the absorbed dose exceeds the preselected value by no more than 15% or does not exceed the absorbed dose equivalent to 0.4Gy at the normal treatment distance.
3.2.7 The control console must be equipped with an irradiation control timer with a time display and be independent of any other control irradiation termination system. When the irradiation is interrupted or terminated, the timer reading must be retained, and the timer must be reset to zero before the next irradiation can be started. 3.2.8 If the equipment is in a state that can produce an absorbed dose rate higher than twice the specified maximum value at the normal treatment distance, an interlock device must be provided to terminate the irradiation when the absorbed dose rate exceeds the specified maximum value by no more than twice. In any case, this interlock device must not be cut off.
Approved by the State Administration of Technical Supervision on May 23, 1996, and implemented on December 1, 1996
GB16369-1996
3.2.9 Dose distribution monitoring devices must be provided for non-straight beam accelerators, and irradiation must be terminated when the relative deviation of the absorbed dose distribution exceeds ±10%.
3.2.10 Facilities for checking all safety interlocks must be equipped to check safety interlocks during irradiation breaks (including interlocks that prevent dose rates from exceeding ten times the preselected value) to ensure the ability of various systems to terminate irradiation and prevent overdose. 3.2.11 Emergency stop switches must be installed in the control console and treatment room respectively. 3.2.12 The software and hardware control programs of accelerators using computer control systems must be encrypted and must not be accessed or modified without permission; once a computer used to monitor interlocks or as part of the measurement circuit or control circuit fails, irradiation must be terminated. 3.3 Limits on stray radiation within the useful beam
3.3.1 The X-ray share during electron beam therapy shall not exceed the requirements of Table 1. Table 1
Electron beam energy E, MeV
Ratio of absorbed dose at 10 cm outside the actual range on the electron beam center axis to the maximum absorbed dose, %<15
3.3.2 During X-ray therapy, under the maximum irradiation field, the absorbed dose on the surface of the center axis shall not exceed the requirements of Table 2. Table 2
Maximum X-ray energy E, MeV
Ratio of absorbed dose on the surface to the maximum absorbed dose, %3.4 Limits on leakage radiation outside the useful beam
3.4.1 At the normal treatment distance, within the cross section of the fixed beam limiter, the ratio of the absorbed dose of leakage radiation through the adjustable beam limiter to the maximum absorbed dose on the center axis of the useful beam shall meet the following limits. 3.4.1.1 During X-ray therapy, it shall not exceed 2% within the irradiation field of 10 cm×10 cm. 3.4.1.2 During electron beam therapy, the average radiation dose in the range from 4 cm outside the 50% isodose curve to the edge of the maximum useful beam shall not exceed 2%.
3.4.1.3 During electron beam therapy, the maximum radiation dose in the range from 2 cm outside the 50% isodose curve to the edge of the maximum useful beam shall not exceed 10%.
3.4.2 Limits for leakage radiation (excluding neutrons) outside the maximum useful beam. 3.4.2.1 At the normal treatment distance, the radiation leakage on the circular plane with a radius of 2m perpendicular to the central axis of the useful beam and with the axis as the center shall not exceed 0.2% (maximum) and 0.1% (average) of the absorbed dose of the central axis of the useful beam. 3.4.2.2 The radiation leakage at 1m away from the electron track shall not exceed 0.5% of the absorbed dose of the central axis of the useful beam at the normal treatment distance. 3.4.3 Neutron leakage radiation outside the maximum useful beam. 3.4.3.1 For accelerators with a nominal X-ray energy greater than 10 MeV, the neutron leakage radiation outside the maximum useful beam shall not exceed 0.05% (maximum) and 0.02% (average) of the absorbed dose of the useful beam center axis within the area specified in 3.4.2.1. 3.4.3.2 The neutron leakage radiation at 1m from the electron track shall not exceed 0.05% of the absorbed dose of the useful beam center axis at the normal treatment distance.
3.5 For indicators such as stability, isocenter, uniformity of irradiation field, and boundary deviation between light field and irradiation field and their test methods, please refer to GB15213.
3.6 Limitation of Induced Radioactivity
For accelerators with a nominal X-ray energy greater than 10MeV, the absorbed dose rate caused by induced radioactivity at 5cm and 1m from the surface of the equipment shall not exceed 0.2mGy·h-1 and 0.02mGy·h-1 respectively.4 Protection requirements for treatment rooms
4.1 The site selection and architectural design of the treatment room must comply with the requirements of GB4792 to ensure the safety of the surrounding environment. 182
GB 16369-1996
4.2 The protective wall (including the ceiling) directly projected by the useful beam shall be designed according to the requirements of primary radiation shielding, and the remaining walls shall be designed according to the requirements of secondary radiation shielding.
4.3 The wires, conduits, etc. passing through the protective wall shall not affect its shielding protection effect. 4.4 For accelerators with a nominal X-ray energy exceeding 10MeV, the shielding design shall take neutron radiation protection into consideration. 4.5 Monitoring and intercom equipment must be installed between the treatment room and the control room. 4.6 The treatment room should have enough usable area. 4.7 A protective door and a maze must be set up at the entrance of the treatment room, and the protective door must be interlocked with the accelerator. 4.8 Irradiation indicator lights and radiation hazard signs must be installed in a conspicuous place outside the treatment room. 4.9 The ventilation frequency of the treatment room should reach 3~4 times per hour. 5 Safety operation requirements
5.1 The accelerator user unit must be equipped with dose measurement equipment such as working dosimeters and water tanks, and should be equipped with radiotherapy quality assurance equipment such as scanners and simulation positioning machines.
5.2 The user unit must have qualified radiotherapy doctors, physical personnel and operating technicians. The operating technicians must undergo radiation health protection and accelerator professional knowledge training, and can only take up their posts after passing the assessment. 5.3 Operators must abide by various operating procedures, carefully check safety interlocks, and it is forbidden to remove safety interlocks at will. It is strictly forbidden to start the machine when the safety interlocks that may cause casualties are removed. 5.4 During the irradiation period, there must be two operators on duty, carefully keep records of the shifts, and strictly implement the handover system. 5.5 Operators are strictly prohibited from leaving their posts without authorization. They must closely monitor the console instruments and patient conditions and handle abnormalities promptly. 5.6 During irradiation, no other personnel are allowed in the treatment room except the patients receiving treatment. 5.7 All kinds of accidents must be prevented. In case of an accident, irradiation must be stopped immediately, the patient must be removed from the radiation field in a timely manner, and the site must be protected to facilitate the correct estimation of the patient's radiation dose and make a reasonable evaluation. 6 Protection Monitoring
6.1 Before the accelerator is installed and put into operation, or when the operating parameters and shielding conditions change, the provincial radiation health protection supervision and monitoring department must conduct comprehensive protection monitoring and radiation safety evaluation of the relevant areas. 6.2 Under normal operation, the radiation level in the workplace and surrounding areas shall be monitored once a year; the safety interlock system shall be checked once a month. 6.3 The personal dose monitoring of operators shall be carried out in accordance with GB5294. 6.4 The calibration of the accelerator dose monitoring system shall be monitored once a week, and the percentage depth dose and uniformity shall be monitored once every six months. 6.5 All monitoring data must be recorded in detail, properly kept, and filed for record. 183
GB16369-1996
Appendix A
Test method
(reference)
A1 The total uncertainty of useful beam measurement should be less than 5%, and the total uncertainty of protection monitoring should be less than 30%. A2 Test of stray radiation within the useful beam
A2.1 Basic test conditions
A2.1.1 The side length of the incident surface of the test phantom (such as a water tank) shall be at least 5 cm longer than the side length of the irradiation field, and its depth shall be at least 5 cm greater than the measurement requirement. A2.1.2 The underwater correction depths for measuring X-rays and electron beams of various energies are as follows: Table Al
Radiation type
X-ray
Electron beam
A2.2 Test of X-ray share during electron beam therapy Nominal energy, MeV
2～10
26～50
5～10
10～20
Correction depth, cm
The incident surface of the phantom is placed at the normal treatment distance, away from the center of the useful beam The axes are perpendicular to each other, and the size of the irradiation field is limited by the beam limiting device. The detector is placed 10 cm outside the actual range on the central axis of the electron beam in the phantom, and the ratio of the absorbed dose to the maximum absorbed dose is measured. A2.3 X-ray surface absorbed dose test
During X-ray treatment, the surface of the phantom is located at the normal treatment distance, and a 30cm×30cm or actual maximum irradiation field (if the maximum irradiation field is less than 30.cm×30cm) is used to measure the ratio of the absorbed dose on the beam axis extrapolated to the surface (0.5mm underwater) to the maximum absorbed dose. All instruments should allow extrapolation to the surface absorbed dose. During the test, all beam limiting devices that can be removed without tools (except the field equalizer) must be removed from under the beam.
A3 Test for radiation leakage outside the useful beam
A3.1 Test for radiation leakage through the beam limiterA3.1.1 During X-ray therapy, the beam limiter should be closed to the minimum position, and the remaining gaps should be weakened by at least two 1/10 layers of absorbing materials. The center of the detector with a maximum cross-section of no more than 1cm2 should be located at the normal treatment distance and the maximum absorbed dose depth in the phantom for testing. When using overlapping beam limiters, the leakage radiation of each set of beam limiters must be tested separately. A3.1.2 During electron beam therapy, at the maximum nominal energy, use the minimum and maximum irradiation field limiters (the maximum irradiation field should be at least 12cm smaller than the existing maximum geometric field) to perform film and detector measurements in turn. First, analyze the film measurement to find the maximum leakage radiation point in the area between 2cm outside the 50% isodose line and the edge of the maximum irradiation field shielded by the beam limiter. Use the corresponding beam limiter to perform detector measurement at the maximum leakage radiation point to verify whether the maximum leakage radiation meets the 10% limit. Detector measurements are made along the X-axis and Y-axis of the irradiation field from 4 cm outside the 50% isodose line to the edge of the maximum irradiation field shielded by the beam limiter. The average value is taken from these four sets of measurements to verify whether the average leakage radiation meets the 2% limit.
A3.2 Maximum useful beam leakage radiation test The adjustable beam limiter is fully closed, and the maximum useful beam cross section is weakened by three 1/10 value layers of absorbing material. From the film measurement, high leakage radiation points are found for detector measurement. X-rays with a nominal energy of 8MeV or electron beams with a maximum nominal energy are used to measure and calculate the average leakage radiation at 16 points as shown in Figure A1 at each nominal energy. 184
GB16369—1996
A3.3 For all nominal energy X-rays, use film to find the maximum leakage radiation points, and use detector measurements at these points to determine whether they meet the requirements of Article 3.4.2.2.
A3.4 Neutron leakage radiation test, X-ray takes the maximum nominal energy, and at the normal treatment distance, 8 points are measured along each main axis of the irradiation field at 20cm from the largest square edge and 100cm from the central axis as shown in Figure A2. The neutron pulse characteristics, neutron energy spectrum, leakage X-rays and indoor neutron radiation effects should be considered in the measurement.
Radiation head-
Radiation source
Beam limiting device
Circle with radius R
[Radius R+3/4·(2R)m
Circle with radius 2m
Normal treatment distance
Radius R+1/1·（2-R)m
Maximum square field size
For measurement pointsbZxz.net
Figure A1 Average leakage radiation 16 measurement points distribution X-ray target
Circle with radius 2㎡ in the treatment plane
- Most square X-ray irradiation field
Figure A2 Distribution of neutron leakage radiation measurement points
A4 Absorbed dose rate test of induced radioactivity 185
GB163691996
For equipment with X-ray nominal energy greater than 10MeV, the irradiation cycle of 4Gy every 10min is continuously operated for 4h, and the measurement is started within 5min after 10s of irradiation termination. The X-ray and electron beam with the maximum nominal energy are taken for measurement, and the irradiation field or light limit is 10 cm×10cm.
Appendix B
Acceptance rules
(reference)
1 Whether the protection performance of the accelerator meets the requirements of this standard shall be inspected and qualified by the technical inspection department of the production unit before the relevant departments can inspect B1
2 The accelerator shall be tested and inspected according to the items specified in this standard before leaving the factory. B2
3 Inspection and acceptance can be carried out in conjunction with the local radiation health protection department, and the inspection results should be submitted to the local radiation health protection department for record. B3
Additional notes:
This standard is proposed by the Ministry of Health of the People's Republic of China. This standard was drafted by the Shanghai Institute of Radiological Medicine, Shanghai Municipal Health and Epidemic Prevention Station, Shanghai Cancer Hospital, and Shanghai Medical Nuclear Instrument Factory.
The main drafters of this standard are Qian Zhilin, Cong Shuyue, Mou Canxing, Sun Zhenxiong, and Zhong Bainiu. This standard is interpreted by the Ministry of Health's Industrial Hygiene Laboratory, the technical coordination unit entrusted by the Ministry of Health. From the date of implementation of this standard, GBW4-81 "Medical High Energy X-ray and Electron Beam Health Protection Regulations" issued by the Ministry of Health will be invalid. 1865mm) absorbed dose to the maximum absorbed dose. All instruments should allow extrapolation to the surface absorbed dose. During the test, all beam limiters that can be removed without tools (except the field equalizer) must be removed from the beam.
A3 Useful beam leakage radiation test
A3.1 Leakage radiation test through beam limiter A3.1.1 During X-ray treatment, the beam limiter should be closed to the minimum position, and the remaining gaps should be weakened by at least two 1/10 layers of absorbing materials. The center of the detector with a maximum cross-section of no more than 1cm2 is located at the normal treatment distance and the maximum absorbed dose depth in the phantom for testing. When using overlapping beam limiters, the leakage radiation of each group of beam limiters must be tested separately. A3.1.2 During electron beam therapy, at the maximum nominal energy, use the minimum and maximum irradiation field limiters (the maximum irradiation field should be at least 12 cm smaller than the existing maximum geometric field) to perform film and detector measurements in turn. First, analyze the film measurement to find the maximum leakage radiation point in the area between 2 cm outside the 50% isodose line and the edge of the maximum irradiation field shielded by the beam limiter. Use the corresponding limiter to perform detector measurements at the maximum leakage radiation point to verify whether the maximum leakage radiation meets the 10% limit. Perform detector measurements along the X and Y axes of the irradiation field from 4 cm outside the 50% isodose line to the edge of the maximum irradiation field shielded by the beam limiter. Take the average value from these four sets of measurements to verify whether the average leakage radiation meets the 2% limit.
A3.2 Maximum useful beam external leakage radiation test The adjustable beam limiter is fully closed, and the maximum useful beam cross section is weakened by three 1/10 value layers of absorbing materials. From the film measurement, find the high leakage radiation point for detector measurement. Use 8MeV nominal energy X-rays or maximum nominal energy electron beams. At each nominal energy, measure and calculate the average leakage radiation at 16 points as shown in Figure A1. 184
GB16369—1996
A3.3 For all nominal energy X-rays, use film to find the maximum leakage radiation point, and use detector measurement at these points to determine whether it meets the provisions of Article 3.4.2.2.
A3.4 Neutron leakage radiation test, X-rays take the maximum nominal energy, and at the normal treatment distance, take the maximum square edge 20cm and 100cm from the central axis along each main axis of the irradiation field for measurement at 8 points as shown in Figure A2. Neutron pulse characteristics, neutron energy spectrum, leakage X-rays and indoor neutron radiation should be considered in the measurement.
Radiation head-
Radiation source
Beam limiting device
Circle with radius R
[Radius R+3/4·(2R)m
Circle with radius 2m
Normal treatment distance
Radius R+1/1·（2-R)m
Maximum square field size
For measurement points
Figure A1 Average leakage radiation 16 measurement points distribution X-ray target
Circle with radius 2㎡ in the treatment plane
- Most square X-ray irradiation field
Figure A2 Distribution of neutron leakage radiation measurement points
A4 Absorbed dose rate test of induced radioactivity 185
GB163691996
For equipment with X-ray nominal energy greater than 10MeV, the irradiation cycle of 4Gy every 10min is continuously operated for 4h, and the measurement is started within 5min after 10s of irradiation termination. The X-ray and electron beam with the maximum nominal energy are taken for measurement, and the irradiation field or light limit is 10 cm×10cm.
Appendix B
Acceptance rules
(reference)
1 Whether the protection performance of the accelerator meets the requirements of this standard shall be inspected and qualified by the technical inspection department of the production unit before the relevant departments can inspect B1
2 The accelerator shall be tested and inspected according to the items specified in this standard before leaving the factory. B2
3 Inspection and acceptance can be carried out in conjunction with the local radiation health protection department, and the inspection results should be submitted to the local radiation health protection department for record. B3
Additional notes:
This standard is proposed by the Ministry of Health of the People's Republic of China. This standard was drafted by the Shanghai Institute of Radiological Medicine, Shanghai Municipal Health and Epidemic Prevention Station, Shanghai Cancer Hospital, and Shanghai Medical Nuclear Instrument Factory.
The main drafters of this standard are Qian Zhilin, Cong Shuyue, Mou Canxing, Sun Zhenxiong, and Zhong Bainiu. This standard is interpreted by the Ministry of Health's Industrial Hygiene Laboratory, the technical coordination unit entrusted by the Ministry of Health. From the date of implementation of this standard, GBW4-81 "Medical High Energy X-ray and Electron Beam Health Protection Regulations" issued by the Ministry of Health will be invalid. 1865mm) absorbed dose to the maximum absorbed dose. All instruments should allow extrapolation to the surface absorbed dose. During the test, all beam limiters that can be removed without tools (except the field equalizer) must be removed from the beam.
A3 Useful beam leakage radiation test
A3.1 Leakage radiation test through beam limiter A3.1.1 During X-ray treatment, the beam limiter should be closed to the minimum position, and the remaining gaps should be weakened by at least two 1/10 layers of absorbing materials. The center of the detector with a maximum cross-section of no more than 1cm2 is located at the normal treatment distance and the maximum absorbed dose depth in the phantom for testing. When using overlapping beam limiters, the leakage radiation of each group of beam limiters must be tested separately. A3.1.2 During electron beam therapy, at the maximum nominal energy, use the minimum and maximum irradiation field limiters (the maximum irradiation field should be at least 12 cm smaller than the existing maximum geometric field) to perform film and detector measurements in turn. First, analyze the film measurement to find the maximum leakage radiation point in the area between 2 cm outside the 50% isodose line and the edge of the maximum irradiation field shielded by the beam limiter. Use the corresponding limiter to perform detector measurements at the maximum leakage radiation point to verify whether the maximum leakage radiation meets the 10% limit. Perform detector measurements along the X and Y axes of the irradiation field from 4 cm outside the 50% isodose line to the edge of the maximum irradiation field shielded by the beam limiter. Take the average value from these four sets of measurements to verify whether the average leakage radiation meets the 2% limit.
A3.2 Maximum useful beam external leakage radiation test The adjustable beam limiter is fully closed, and the maximum useful beam cross section is weakened by three 1/10 value layers of absorbing materials. From the film measurement, find the high leakage radiation point for detector measurement. Use 8MeV nominal energy X-rays or maximum nominal energy electron beams. At each nominal energy, measure and calculate the average leakage radiation at 16 points as shown in Figure A1. 184
GB16369—1996
A3.3 For all nominal energy X-rays, use film to find the maximum leakage radiation point, and use detector measurement at these points to determine whether it meets the provisions of Article 3.4.2.2.
A3.4 Neutron leakage radiation test, X-rays take the maximum nominal energy, and at the normal treatment distance, take the maximum square edge 20cm and 100cm from the central axis along each main axis of the irradiation field for measurement at 8 points as shown in Figure A2. Neutron pulse characteristics, neutron energy spectrum, leakage X-rays and indoor neutron radiation should be considered in the measurement.
Radiation head-
Radiation source
Beam limiting device
Circle with radius R
[Radius R+3/4·(2R)m
Circle with radius 2m
Normal treatment distance
Radius R+1/1·（2-R)m
Maximum square field size
For measurement points
Figure A1 Average leakage radiation 16 measurement points distribution X-ray target
Circle with radius 2㎡ in the treatment plane
- Most square X-ray irradiation field
Figure A2 Distribution of neutron leakage radiation measurement points
A4 Absorbed dose rate test of induced radioactivity 185
GB163691996
For equipment with X-ray nominal energy greater than 10MeV, the irradiation cycle of 4Gy every 10min is continuously operated for 4h, and the measurement is started within 5min after 10s of irradiation termination. The X-ray and electron beam with the maximum nominal energy are taken for measurement, and the irradiation field or light limit is 10 cm×10cm.
Appendix B
Acceptance rules
(reference)
1 Whether the protection performance of the accelerator meets the requirements of this standard shall be inspected and qualified by the technical inspection department of the production unit before the relevant departments can inspect B1
2 The accelerator shall be tested and inspected according to the items specified in this standard before leaving the factory. B2
3 Inspection and acceptance can be carried out in conjunction with the local radiation health protection department, and the inspection results should be submitted to the local radiation health protection department for record. B3
Additional notes:
This standard is proposed by the Ministry of Health of the People's Republic of China. This standard was drafted by the Shanghai Institute of Radiological Medicine, Shanghai Municipal Health and Epidemic Prevention Station, Shanghai Cancer Hospital, and Shanghai Medical Nuclear Instrument Factory.
The main drafters of this standard are Qian Zhilin, Cong Shuyue, Mou Canxing, Sun Zhenxiong, and Zhong Bainiu. This standard is interpreted by the Ministry of Health's Industrial Hygiene Laboratory, the technical coordination unit entrusted by the Ministry of Health. From the date of implementation of this standard, GBW4-81 "Medical High Energy X-ray and Electron Beam Health Protection Regulations" issued by the Ministry of Health will be invalid. 1864 Neutron leakage radiation test, X-ray takes the maximum nominal energy, and at the normal treatment distance, 8 points are measured along each main axis of the irradiation field at 20cm from the largest square edge and 100cm from the central axis as shown in Figure A2. The neutron pulse characteristics, neutron energy spectrum, leakage X-rays and indoor neutron radiation effects should be considered in the measurement.
Radiation head-
Radiation source
Beam limiting device
Circle with radius R
[Radius R+3/4·(2R)m
Circle with radius 2m
Normal treatment distance
Radius R+1/1·（2-R)m
Maximum square field size
For measurement points
Figure A1 Average leakage radiation 16 measurement points distribution X-ray target
Circle with radius 2㎡ in the treatment plane
- Most square X-ray irradiation field
Figure A2 Distribution of neutron leakage radiation measurement points
A4 Absorbed dose rate test of induced radioactivity 185
GB163691996
For equipment with X-ray nominal energy greater than 10MeV, the irradiation cycle of 4Gy every 10min is continuously operated for 4h, and the measurement is started within 5min after 10s of irradiation termination. The X-ray and electron beam with the maximum nominal energy are taken for measurement, and the irradiation field or light limit is 10 cm×10cm.
Appendix B
Acceptance rules
(reference)
1 Whether the protection performance of the accelerator meets the requirements of this standard shall be inspected and qualified by the technical inspection department of the production unit before the relevant departments can inspect B1
2 The accelerator shall be tested and inspected according to the items specified in this standard before leaving the factory. B2
3 Inspection and acceptance can be carried out in conjunction with the local radiation health protection department, and the inspection results should be submitted to the local radiation health protection department for record. B3
Additional notes:
This standard is proposed by the Ministry of Health of the People's Republic of China. This standard was drafted by the Shanghai Institute of Radiological Medicine, Shanghai Municipal Health and Epidemic Prevention Station, Shanghai Cancer Hospital, and Shanghai Medical Nuclear Instrument Factory.
The main drafters of this standard are Qian Zhilin, Cong Shuyue, Mou Canxing, Sun Zhenxiong, and Zhong Bainiu. This standard is interpreted by the Ministry of Health's Industrial Hygiene Laboratory, the technical coordination unit entrusted by the Ministry of Health. From the date of implementation of this standard, GBW4-81 "Medical High Energy X-ray and Electron Beam Health Protection Regulations" issued by the Ministry of Health will be invalid. 1864 Neutron leakage radiation test, X-ray takes the maximum nominal energy, and at the normal treatment distance, 8 points are measured along each main axis of the irradiation field at 20cm from the largest square edge and 100cm from the central axis as shown in Figure A2. The neutron pulse characteristics, neutron energy spectrum, leakage X-rays and indoor neutron radiation effects should be considered in the measurement.
Radiation head-
Radiation source
Beam limiting device
Circle with radius R
[Radius R+3/4·(2R)m
Circle with radius 2m
Normal treatment distance
Radius R+1/1·（2-R)m
Maximum square field size
For measurement points
Figure A1 Average leakage radiation 16 measurement points distribution X-ray target
Circle with radius 2㎡ in the treatment plane
- Most square X-ray irradiation field
Figure A2 Distribution of neutron leakage radiation measurement points
A4 Absorbed dose rate test of induced radioactivity 185
GB163691996
For equipment with X-ray nominal energy greater than 10MeV, the irradiation cycle of 4Gy every 10min is continuously operated for 4h, and the measurement is started within 5min after 10s of irradiation termination. The X-ray and electron beam with the maximum nominal energy are taken for measurement, and the irradiation field or light limit is 10 cm×10cm.
Appendix B
Acceptance rules
(reference)
1 Whether the protection performance of the accelerator meets the requirements of this standard shall be inspected and qualified by the technical inspection department of the production unit before the relevant departments can inspect B1
2 The accelerator shall be tested and inspected according to the items specified in this standard before leaving the factory. B2
3 Inspection and acceptance can be carried out in conjunction with the local radiation health protection department, and the inspection results should be submitted to the local radiation health protection department for record. B3
Additional notes:
This standard is proposed by the Ministry of Health of the People's Republic of China. This standard was drafted by the Shanghai Institute of Radiological Medicine, Shanghai Municipal Health and Epidemic Prevention Station, Shanghai Cancer Hospital, and Shanghai Medical Nuclear Instrument Factory.
The main drafters of this standard are Qian Zhilin, Cong Shuyue, Mou Canxing, Sun Zhenxiong, and Zhong Bainiu. This standard is interpreted by the Ministry of Health's Industrial Hygiene Laboratory, the technical coordination unit entrusted by the Ministry of Health. From the date of implementation of this standard, GBW4-81 "Medical High Energy X-ray and Electron Beam Health Protection Regulations" issued by the Ministry of Health will be invalid. 186
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