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1.
Chinese Journal of Radiological Health ; (6): 1-6, 2024.
Artículo en Chino | WPRIM | ID: wpr-1012758

RESUMEN

Objective @#To verify the feasibility of using a homemade lung phantom for quality control of Cyberknife by comparing the measurement results of the homemade lung phantom and CIRS dynamic phantom in E2E testing of Cyberknife lung tracking. @*Methods  @#The patient treatment process was simulated, including CT positioning, plan design, irra- diation implementation, film scanning, and analysis using the homemade phantom and CIRS phantom. The two phantoms were measured five times using MLC under the S7 generation Cyberknife and five times using Iris under the M6 generation Cyberknife. The differences in measurement results between the two phantoms were analyzed using independent sample t-test.@*Results @#For the S7 generation Cyberknife, the statistical analysis of differences between the two phantoms in the detection values on the X-axis, Y-axis, Z-axis, and total deviation showed P values of 0.236, 0.175, 0.289, and 0.668, respect- ively. For the M6 generation Cyberknife, the statistical analysis showed P values of 0.880, 0.891, 0.573, and 0.433, respect- ively. The P values were all > 0.05. Therefore, there were no statistically significant differences in the detection results between the homemade lung phantom and the CIRS phantom under the S7 and M6 generation Cyberknife. The total deviation values were <1.5 mm.@*Conclusion  @#The homemade lung phantom and CIRS phantom have consistent measurement results in the E2E testing of Cyberknife lung tracking and meet the requirements of Report of AAPM TG-135 and WS 667- 2019 standard. Therefore, the homemade lung phantom is feasible for clinical quality control of Cyberknife.

2.
Journal of Biomedical Engineering ; (6): 973-981, 2023.
Artículo en Chino | WPRIM | ID: wpr-1008923

RESUMEN

Ultra-rapid cooling and rewarming rate is a critical technical approach to achieve ice-free cells during the freezing and melting process. A set of ultra-rapid solid surface freeze-thaw visualization system was developed based on a sapphire flim, and experiments on droplet freeze-thaw were carried out under different cryoprotectant components, volumes and laser energies. The results showed that the cooling rate of 1 μL mixed cryoprotectant [1.5 mol/L propylene glycol (PG) + 1.5 mol/L ethylene glycol (EG) + 0.5 mol/L trehalose (TRE)] could be 9.2×10 3 °C/min. The volume range of 1-8 μL droplets could be vitrified. After comparing the proportions of multiple cryoprotectants, the combination of equal proportion mixed permeability protectant and trehalose had the best vitrification freezing effect and more uniform crystallization characteristics. During the rewarming operation, the heating curve of glassy droplets containing gold nanoparticles was measured for the first time under the action of 400-1 200 W laser power, and the rewarming rate was up to the order of 10 6 °C/min. According to the droplet images of different power rewarming processes, the laser power range for ice-free rewarming with micron-level resolution was clarified to be 1 400-1 600 W. The work of this paper simultaneously realizes the ultra-high-speed temperature ramp-up, transient visual observation and temperature measurement of droplets, providing technical means for judging the ice free droplets during the freeze-thaw process. It is conducive to promoting the development of ultra-rapid freeze-thaw technology for biological cells and tissues.


Asunto(s)
Congelación , Vitrificación , Criopreservación/métodos , Trehalosa , Oro , Recalentamiento , Nanopartículas del Metal , Crioprotectores , Rayos Láser
3.
Chinese Journal of Radiological Health ; (6): 661-667, 2023.
Artículo en Chino | WPRIM | ID: wpr-1006324

RESUMEN

Objective To address the absence of matrix specified for the determination of intrinsic uniformity in the current standard, and to investigate the effect of source distances on intrinsic spatial linearity, the intrinsic uniformity and intrinsic spatial linearity of 16 probes in eight SPECT devices were measured and analyzed with different matrices and source distances, in order to determine the optimal measurement conditions. Methods According to the standard Specification for Testing of Quality Control in Gamma Cameras and Single Photon Emission Computed Tomograph (SPECT) (WS 523—2019), the intrinsic uniformity was measured using 64 × 64 and 256 × 256 matrices and the intrinsic spatial linearity was measured using of 1.7 and 3 m source distances. Results When intrinsic uniformity was measured with the 64 × 64 matrix, more than 50% of the probes showed lower values. When intrinsic spatial linearity was measured with the 3 m source distance, more probes showed lower values. Conclusion The 64 × 64 matrix is recommended for the determination of intrinsic uniformity and a source distance of >5 FOV is recommended for the measurement of intrinsic spatial linearity.

4.
Chinese Journal of Radiological Medicine and Protection ; (12): 614-619, 2023.
Artículo en Chino | WPRIM | ID: wpr-993133

RESUMEN

Objective:To provide reference for establishing the testing method for quality control of neutron beam in boron neutron capture therapy (BNCT) equipment in China by testing the radiation characteristic parameters and dosimetry characteristic parameters of epithermal neutron beam in hospital neutron irradiator (IHNI).Methods:By comparing the uncertainties in the result of various test items with the deviation values recommended by the European Joint Research Center (EC-JRC), the feasibility of the relevant of testing method was analyzed and evaluated.Results:The uncertainty in epithermal neutron fluence rate was 2.7%. The uncertainty in ratio of thermal to epithermal neutron fluence rate was 3.1%. The uncertainty in ratio of fast neutron air kerma to epithermal neutron fluence rate was 9.3%. The uncertainty in ratio of gamma air kerma to epithermal neutron fluence rate was 8.7%. The uncertainty in spatial distribution of neutron fluence rate was 2.7%. The uncertainty in thermal neutron fluence rate in phantom was 1.8%. The uncertainty in neutron and gamma-ray dose rate in phantom was 17.1% and 4.0%, respectively.Conclusions:The uncertainty in neutron dose rate measurement result in phantom is higher, and further research is needed to improve the accuracy of the testing method. The uncertainty in the measurement result of other test items is lower, and the accuracy of the test result is expected to meet the allowable deviation value recommended by the European Joint Research Center, and the test method is feasible.

5.
Chinese Journal of Radiological Medicine and Protection ; (12): 440-446, 2023.
Artículo en Chino | WPRIM | ID: wpr-993110

RESUMEN

Objective:To study the healthcare level (HCL) in China and its influencing factors.Methods:By using the data reported in the China statistical yearbook published by the National Bureau of Statistics and in other public literature, HCL was calculated in terms of the number of population and physicians in the whole country and various provinces. Multiple regression was used to analyze the relationship between HCL and regional population, area, number of administrative divisions and gross domestic product (GDP). Pearson correlation analysis was applied to analyze the relationship between healthcare level and medical radiation frequency. Results:Since 2015, Chinese HCL value was lower than 1 000, but there were two provinces with HCL value greater than 1 000 in 2019. Population and GDP were the influencing factors for the HCL, with correlation coefficients of 0.416 and -0.583, respectively. There was a correlation between HCL and medical exposure frequency of Chinese population( r= -0.620, P=0.028). Conclusions:Chinese HCL value was 542 in 2020, but there has been great differences between various provinces. HCL as an indicator of medical exposure assessment needs further research in China.

6.
Chinese Journal of Radiological Health ; (6): 230-234, 2023.
Artículo en Chino | WPRIM | ID: wpr-978420

RESUMEN

Objective To explore the feasibility of quartz glass for radiotherapy dosimetry through the experimental study of the thermoluminescence characteristics of synthetic quartz glass. Methods The thermoluminescence glow curves of quartz glass under different annealing conditions were analyzed, the thermoluminescence characteristics of quartz glass were studied, and the measurement parameters were optimized. Using the Co-60 reference radiation field in the National Secondary Standard Dosimetry Laboratory, the quartz glass samples under different annealing conditions were irradiated following the dose levels of radiotherapy, i.e., 0.5, 1.0, 2.0, 4.0, 6.0, 8.0, and 10.0 Gy, respectively. According to the relationship between the absorbed dose of quartz glass and the relative thermoluminescence signal intensity, the linearity and dispersion of the dose response of quartz glass were obtained, and the feasibility of quartz glass for radiotherapy dosimetry was analyzed. Results The linear correlation coefficient of dose response of quartz glass under annealing condition of 430℃ for 10 min was 0.9984, and the dose response dispersion was 0.97% at the absorbed dose of 2 Gy. The linear correlation coefficient of dose response of quartz glass under annealing condition of 600℃ for 1 h was 0.9911, and the dose response dispersion was 1.4% at the absorbed dose of 2 Gy. Conclusion Preliminary results suggest that quartz glass with annealing condition of 430℃ for 10 min has the potential to be used for radiotherapy dosimetry.

7.
Chinese Journal of Radiological Health ; (6): 119-124, 2023.
Artículo en Chino | WPRIM | ID: wpr-973163

RESUMEN

@#<b>Objective</b> To obtain the medical exposure frequency data of residents through a questionnaire survey on mobile phone networks in the community, and to analyze the main influencing factors. <b>Methods</b> A snowball sampling method was used to expand the sampling from medical staff in a county hospital to the community. The questionnaire included personal information such as occupation category, type of medical insurance, and education level as well as basic radiation-related knowledge and medical exposure type and frequency of respondents received in 2021. A logistic regression model was used to analyze the influencing factors of medical exposure. <b>Results</b> A total of 223 respondents were investigated, and 12.56% of them received radiological diagnosis and radiotherapy in 2021. The proportion of males receiving medical exposure was significantly higher than that of females (19.64% <i>vs</i> 10.18%). The likelihood of the person receiving medical exposure increased considerably with age, with the proportion of residents receiving medical exposure at 20, 30, 40, and 50 years of age being 6.25%, 7.95%, 19.23%, and 33.33%, respectively. Of persons who received medical exposure, 57.14% underwent CT scans. Persons participating in the new rural cooperative medical system were likely less to receive radiological diagnosis and radiotherapy than urban workers and residents (<i>OR</i> = 0.55, <i>CI</i>:0.13-2.23, <i>P</i> > 0.05). <b>Conclusion</b> Questionnaire survey in the community can obtain more information about the medical exposure of residents, and age and type of medical insurance are important factors affecting the frequency of medical exposure.

8.
Chinese Journal of Radiological Medicine and Protection ; (12): 787-792, 2022.
Artículo en Chino | WPRIM | ID: wpr-956861

RESUMEN

Objective:To analyze the influencing factors on initial testing qualified rate of condition monitoring of digital radiography (DR) devices in China and provide the scientific basis for key points of national medical radiation protection monitoring work.Methods:The data of quality control detection of DR devices, reported by 31 provinces in 2020, were collected from National Radiation Health Information Platform-National Medical Radiation Protection Monitoring System. Logistic regression was used to analyze the related influencing factors of initial testing qualified rate of condition monitoring of DR devices.Results:The result of logistic regression analysis showed that the nature of radiological health technical service institutions, the level of medical and health institution and the regions where they are located in China were the independent influencing factors of initial testing qualified rate of condition monitoring of DR devices ( χ2=15.41-21.18, P < 0.05). Private institution group ( OR=1.714, 95% CI: 1.310-2.243), tertiary hospital group ( OR=1.710, 95% CI: 1.310-2.232) and secondary hospital group ( OR=1.540, 95% CI: 1.203-1.971) had a higher qualified probability of DR devices, while western region group ( OR=0.670, 95% CI: 0.526-0.852) had a lower qualified probability of DR devices. Conclusions:Supervision on quality control of DR devices should be strengthened, such as strengthening the random inspection and double-check to the devices. And great attention should be paid to the quality control testing of DR devices in the western China and in the primary and ungraded hospitals.

9.
Chinese Journal of Radiological Medicine and Protection ; (12): 454-459, 2022.
Artículo en Chino | WPRIM | ID: wpr-956806

RESUMEN

Objective:To analyze the radiological protection situation in the workplace of medical X-ray diagnostic equipment in primary medical institutions in south Xinjiang Uygur Autonomous Region, and then put forward necessary measures and suggestions.Methods:In accordance with the national medical radiation protection monitoring program and the requirements of relevant standards for radiological health, medical X-ray diagnostic equipment in radialogical diagnosis and treatment institutions was tested selectively for workplace radiological protection, with the result statistically analyzed.Results:From 2018 to 2021, radiological protection test was conducted for 84 workplaces in 15 radiological diagnosis and treatment institutions in 4 districts of south Xinjiang, with a pass rate of 98.8%, which was consistent with the mainland including the eastern and central regions in the country.Conclusions:Based on the current situation in radiological diagnosis and treatment institutions on medical radiation protection in south Xinjiang, it is recommended to strengthen the supervision and management of radiological diagnosis and treatment equipment, improve the testing and technical capabilities of the local medical radiation monitoring technical teams and raise the level of radiological health work in the south Xinjiang.

10.
Chinese Journal of Radiological Health ; (6): 669-673, 2022.
Artículo en Chino | WPRIM | ID: wpr-965541

RESUMEN

@#<b>Objective</b> To calculate the energy dependence of absorbed dose in EBT3 film, and to reveal the error in the measurement of proton absorbed dose by EBT3 film. <b>Methods</b> Beam energy was gradually increased in the clinical photon and proton energy ranges. Geant4 was used to calculate the difference in absorbed dose between EBT3 film and the same volume of water. The results were compared with the theoretical values. <b>Results</b> For photons and protons, the thresholds for absorbed dose with energy dependence were 100 keV and 11 MeV, respectively. The energy dependence was consistent with the theoretical values when the photon and proton energies were higher than the corresponding thresholds, and irrelevant to the theoretical values when energies were lower than the thresholds. The differences between the proton Bragg peak and 50% dose point and the actual positions were less than 1%. <b>Conclusions</b> For protons and photons with high energy, the energy dependence of absorbed dose in EBT3 film is negligible. For protons and photons with low energy, EBT3 film shows very different energy dependence of absorbed dose, which should be taken into consideration. The proton Bragg peak and 50% dose point measured by EBT3 film are basically the same as the actual positions.

11.
Chinese Journal of Radiological Health ; (6): 645-650, 2022.
Artículo en Chino | WPRIM | ID: wpr-965463

RESUMEN

Objective@#To discuss the feasibility of applying home-made auto quality assurance (AQA) phantom in Cyberknife AQA test.@*Methods@#The same treatment plan for AQA test was designed in the Cyberknife treatment planning system. The AQA tests were performed under the same conditions using the home-made AQA phantom and the AQA phantom in the fourth-generation (G4) Cyberknife mode and the fifth-generation (VSI) Cyberknife mode, respectively, and each measurement was repeated five times to analyze and compare the differences in test results between the two phantoms.@*Results@#The total deviations of the home-made AQA phantom and the AQA phantom in the AQA test under the G4 Cy- berknife mode were (0.28 ± 0.12) mm and (0.28 ± 0.15) mm, respectively (P > 0.05); the test results under the VSI Cy- berknife mode were (0.46 ± 0.19) mm and (0.50 ± 0.07) mm, respectively (P > 0.05); the total deviations of all test results were smaller than 1.0 mm, which met the requirements of WS 667—2019 Specification for Testing of Quality Control in Ro- botic Arm Radiotherapy Device.@*Conclusion@#The test results of the home-made AQA phantom and the AQA phantom are consistent in the AQA test, and the home-made AQA phantom can be used for Cyberknife quality control.

12.
Chinese Journal of Radiological Medicine and Protection ; (12): 450-455, 2021.
Artículo en Chino | WPRIM | ID: wpr-910337

RESUMEN

Objective:To analyze the distribution of radiodiagnosis resources in China and provide data support for further optimizing the allocation of radiodiagnosis resources and improving the weaknesses in radiation protection.Methods:The survey was carried out in accordance with the unified plan and using questionnaires of the national medical radiation protection monitoring program issued from 2017 to 2019. The survey included all medical institutions performing radiodiagnosis in China. The survey indicators included distribution of medical institutions performing radiodiagnosis, number of equipment, number of radiation workers and other information, the allocation of radiation protection equipment and the frequency of radiodiagnosis. The survey was performed using questionnaire survey and reported through the national medical radiation protection monitoring information system. In terms of the organization code, the name of the organizations excludes those repeatedly reported. The original data was exported in the form of excel table from the database for the purpose of statistical analysis.Results:By the end of 2019, except Xinjiang Production and Construction Corps, Hong Kong, Macao and Taiwan regions and military systems, there were 68 924 diagnostic radiology medical institutions in China, 147 913 diagnostic radiology equipment, accounting for 91.7% of the total pieces of nationwide diagnostic radioprotective equipment. There are 367 201 radiologists in China, accounting for 76.1% of 406 830 radiologists in all medical institutions, with high allocation rate of radiation protection equipment. However, the allocation rate in first-class hospitals was the lowest among all levels of hospitals. The piece of protection equipment was increased with the grade of hospital. From perspective of of economic development level, the highest was found in the eastern region, with the lowest in the central and northeast region, both of which are about 90%.Conclusions:The current status of radiodiagnosis and protection was ascertained basically through this three-year round of survey, with a large number of survey data accumulated. This survey provides data support for the development of relevant protection policies and standards at national and provincial levels. Survey data indicated that there are still nearly 1 000 direct fluorescent screen fluoroscopy machines in use in China. Relevant policies and standards should be established to gradually phase out the equipment with serious radiation hazards.

13.
Chinese Journal of Radiological Medicine and Protection ; (12): 276-281, 2021.
Artículo en Chino | WPRIM | ID: wpr-910307

RESUMEN

The rapid development of medical application of ionizing radiation has seen a range of safety and protection problems that might be of importance. This paper aims to introduce the current situation and existing problems in the public medical exposure, and to propose the relevant suggestions, based on a combination of judgment of medical radiation exposure justification, quality assurance and control of equipment in radiodiagnosis and radiotherapy, occupational protection of radiation workers, and health effects on patients undergoing radiodiagnosis and radiotherapy.

14.
Chinese Journal of Radiological Health ; (6): 38-43, 2021.
Artículo en Chino | WPRIM | ID: wpr-973716

RESUMEN

0bjective To study the angular dependence of optically stimulated luminescent dosimeter (OSLD) with solid phantoms under SSDL radiation level 60Co radiation field, and to discuss the possibility of OSLD in volumetric modulated arc therapy (VMAT) and other rotating irradiation dose audit. Methods OSLDs were embedded in the two phantoms with the same size and material, respectively. The phantom 1 was set to make the first OSLD perpendicular to the beam, and the phantom 2 was set to make the second OSLD parallel to the beam. The OSLDs were irradiated at 8 angles: 0°, 45°, 90°, 135°, 180°, −45°, −90, −135°. The counts of the OSLSs were read and the response of each angle which normalized to 0° were calculated. Results When the OSLDs are perpendicular to the beam, the angular response is between −6.76% ~ +1.5%, with the maximum angular dependence at 90° and −90°. When the OSLDs are parallel to the beam, the angular response is between −1.74%~+1.67%, below 2%. Conclusion It is better to correct the sensitivity of dosimeters by Element Correction Factors (ECF) for dose audit. Under the condition of rotating irradiation, OSLD shoud be set parallel to the beam, which can better reduce the influence of angular dependence and facilitate further application research of VMAT dose audit.

15.
Chinese Journal of Radiological Medicine and Protection ; (12): 321-325, 2020.
Artículo en Chino | WPRIM | ID: wpr-868444

RESUMEN

Objective:To estimate the induced radioactive 56Mn and its level of iron in heavy concrete shielding wall due to neutron activation during tumor proton therapy. Methods:A Geant4 program was adopted to build the model of a heavy concrete shielding wall in a proton therapy room, simulate secondary neutrons generated by 245 MeV proton beam irradiating water phantom. The statistical distribution of radionuclide 56Mn in shielding wall was calculated. The shielding wall was layered every 10 cm thickness, the dose equivalent rate of radionuclide 56Mn in the first three shielding walls was calculated. Results:Under the maximum beam irradiation conditions (1.872 × 10 10), the number of radionuclide 56Mn in the first three layers of shielding walls are 3.10×10 8, 1.60×10 8, 9.33×10 8. The ambient dose equivalent rate at a distance of 1 m from the treatment room are 2.13×10 -3, 8.82×10 -4, 9.10×10 -4 μSv/h, and the total ambient dose equivalent rate for the first three layers was 3.92× 10 -3 μSv/h. Conclusions:During proton therapy, the shielded walls near the central axis of the beam produce more induced radioactivity. The induced radioactivity produced by the neutron-activated iron element at the ahead of the shielding wall is the strongest, and decreases exponentially as the thickness of the shield wall increases.The induced radioactivity in front of the shielding wall of proton therapy room should be concerned.

16.
Chinese Journal of Radiological Medicine and Protection ; (12): 210-214, 2018.
Artículo en Chino | WPRIM | ID: wpr-708043

RESUMEN

Objective To evaluate the secondary cancer risk to various organs due to radiation treatment for early left-sided breast cancer using 6 MV X-ray flattening filter free (FFF) and flattening filter (FF) modes.Methods Two techniques,6 MV FFF and 6 MV FF X-rays modes,were used to develop the two tangential fields d-IMRT plans for 20 early left-sided breast cancer patients respectively.For all the patients,the dose to surrounding tissues was minimized as low as possible,the 95% volume of the planning target volume (PTV) and clinical target volume (CTV) was consistent with the prescribed dose.The beam parameters and the plan optimization parameters of FFF modes were in consonance with FF modes.The radiation doses and volumes of the planning target volumes,organs at risk and normal tissue were detected by dose-volume histogram.And then,the excess absolute risk(EAR) of contralateral breast,ipsilateral lung,contralateral lung,thyroid and liver were calculated using the radiotherapy-induced secondary primary cancer risks models.Results The treatment plans of two groups met the requirements of clinical.The FFF d-IMRT techniques resulted in a systematic reduction of the organ equivalent dose (OED) (t =2.18-9.72,P < 0.05),and the EAR (t =2.11-9.99,P < 0.05) of contralateral breast,ipsilateral lung,contralateral lung,thyroid and liver was compared to the FF IMRT techniques,especially for the contralateral breast.Conclusions Both FFF and FF d-IMRT plans can achieve comparable target dose coverage in patients with early left-sided breast cancer,while the FFF d-IMRT techniques could reduce the excess absolute risk of contralateral breast,ipsilateral lung,contralateral lung,thyroid and liver.These results are of clinical importance,especially for the early-stage patients with an overall good prognosis.

17.
Chinese Journal of Radiological Medicine and Protection ; (12): 298-301, 2017.
Artículo en Chino | WPRIM | ID: wpr-512180

RESUMEN

Objective To study the difference of the constructed doses between electronic portal imaging device (EPID) and dynalogs files of linac for in vivo phantom dosimetry.Methods Twelve pelvic patients treated with volumetric modulated arc therapy (VMAT) plans were selected and the information of each plan was copied to theCheese phantom to recalculate the doses before delivered on Varian RapidArc Linac.TheCheese phantom was placed on the isocenter and the electronic portal image (EPI) formed by the EPID was sent to EPIgray software to reconstruct the actual delivered doses.Meanwhile,dynalogs files were respectively imported to the Mobius software to reconstruct the actual delivered doses too.The point dose in the center of each VMAT plan (the center of the effective sensitive volume of ionization chamber) was measured by the A1SL ionization chamber.At the same time,the dose of sensitive volume of ionization chamber from treatment planning systcm (TPS) was recorded.Results The relative deviation between the dose from TPS and the measurement results by the ionization chamber was 1.13%.The difference between the reconstructed doses of EPID-based or the dynalogs file-based with the measurement results by the ionization chamber was not statistically significant (P > 0.05).Conclusions The two methods of dose reconstruction can provide reference for in vivo dosimetry of VMAT.

18.
Chinese Journal of Radiological Medicine and Protection ; (12): 626-629, 2017.
Artículo en Chino | WPRIM | ID: wpr-611154

RESUMEN

Objective To study the step aceuracy of 252Cf neutron afterloading radiotherapy machine and the dose deviation caused by step deviation.Methods EBT3 film was used to measure the steps of the 252Cf neutron source,and then the center of each 252Cf neutron source was identified by measuring the optical density value by using the ImageJ software.Double ion chambersmethod was used to measure the dose deviation dlue to the 252 Cf neutron source position shift.Results 252 Cf neutron source step accuracy may amount to 0.01 mm using EBT3 film measurement,when 252Cf neutron source position deviation is less than 3 mm,the dose deviation is less than 2.5%.Conclusions The study on the step accuracy and position deviation of the 252Cf neutron source can provide a reference for the quality control standard of the 252Cf neutron afterloading radiotherapy machine.

19.
Chinese Journal of Radiological Medicine and Protection ; (12): 626-629, 2016.
Artículo en Chino | WPRIM | ID: wpr-496869

RESUMEN

Objective To develop the method for testing the consistency of irradiation field produced by the active spot scanning proton and heavy ion accelerator.Methods Calibration of the EBT3 films were carried out with the calibrated ion beam to establish the dose calibration curve.According to the different proton and carbon ion energies (proton:94.29,150.68,212.62 McV;carbon ion:175.99,283.43,412.54 MeV/u),EBT3 films were located in the solid water phantoms in each therapy room,respectively.Finally,the irradiated EBT3 films were scanned and the radiation field size's deviation and flatness were analyzed.Results In different conditions,radiation field size's deviations were all less than 2 mm and the flatness parameters were all controlled below the 5%.Conclusions EBT3 films can be used to test the active spot scanning proton and heavy ion accelerator's radiation field uniformity.

20.
Chinese Journal of Radiological Medicine and Protection ; (12): 621-625, 2016.
Artículo en Chino | WPRIM | ID: wpr-496842

RESUMEN

Objective To study the quality testing of dose delivery system of the active spot scanning proton and heavy ion accelerator,in order to provide the reference for the quality control of related equipment.Methods In the four therapy rooms,both 0.6 cc chambers and Gafchromic EBT3 films were used,respectively,to test the accelerator for dose reproducibility,dose linearity,dose stability,depth dose distribution,beam scanning position deviation and radiation field uniformity in each therapy room.Results Dose reproducibility variation coefficients are all less than 1.5%,dose linearity's maximum deviations less than 2%,dose stability's deviations less than 2%,depth dose distribution stability within 2%,beam scanning position deviation less than 1 mm,consistency of irradiation field's deviation less than 2 mm,and flatness within ± 5%.Conclusions The indicators about quality testing for the active spot scanning proton and heavy ion accelerator are all in line with the requirements of IEC standards draft.

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