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@#Operational quantities, which are used to estimate protection quantities in the field of radiation protection, are important in area monitoring. The current operational quantities show certain limitations as the particle types and energy ranges are expanded. The International Commission on Radiation Units and Measurements Report 95 proposed a new system of operational quantities, where the definitions and phantoms of the operational quantities are consistent with the protection quantities, enabling better estimation of the protection quantities over wider ranges of particle types and energies. This paper focuses on the effects of the new recommended operational quantity system in area monitoring from the aspects of phantom application, conversion coefficient updating, and monitor design and calibration.
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Objective:To determine the peak skin dose (PSD) to patients from neuro-interventional procedures and evaluate the risk of the deterministic effect.Methods:Gafchromic XR RV3 films were used in a level A tertiary hospital in Beijing to measure the patients′ PSD from neuro-interventional procedures, mainly three common types of procedures, including vascular embolization, vascular angioplasty and vascular angiography. The films were scanned by Epson Expression 10000XL, read by ImageJ software, and analyzed by Film QA Pro?2014 software.Results:PSD was measured in 23 embolizations, 14 stentings and 12 arteriography. There were 20 patients whose PSD were equal or greater than 2 Gy, including 15 in vascular embolization and 5 in angioplasty. The PSDs to patients in cerebral arteriography were all below 2 Gy. The PSDs to some of the patients were higher than the threshold for deterministic effect recommended by ICRP Publication 118.Conclusions:There is a risk of deterministic effect in neurointerventional procedures. It is suggested that the patients be followed up to observe their radiation injury as well as to know in time the subsequent diagnosis and treatment.
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Objective To establish a method for reducing the dose to the eye lens of interventional staff,and provide the data basis for improving radiological protection measures.Methods One piece of interventional equipment coupled with conventional auxiliary protective devices and two types of common neural interventional procedures were selected to monitor 46 and 35 procedures before and after the device modification.The doses to the eye lens of staff were measured with direct-reading dosimeters for analysis of dose trends.Results After modification of the devices,the average dose to the left eye lens decreased from (9.71 ±10.86) to (3.23 ±5.59) μSv for the first operator,from (9.51 ± 12.34) to (0.68 ± 0.78) μSv for the second in cerebral angiography;whereas the dose decreased from (14.83 ± 19.13) to (4.17±4.59) for the first operator and from (14.12±21.76) to (1.23 ±1.57)μSv for the second in embolization procedure,respectively.The left eye lens doses measured before and after the modification showed significant difference (U =-2.760,-2.467,-1.967,-2.655,P ＜0.05).Conclusions The modification of the auxiliary radiological protective devices may effectively reduce the dose to the eye lens dose.This method was shown to be feasible for the improvement of radiological protection of interventional staff.
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Objective:To establish the X-ray standard was used to calibrate Hp(3) dosimeter in order to satisfy the requirement of eye-lens dose equivalents for the radiological occupational staff.Methods:The conventional values (Hp(3)) on the reference point of the narrow beams of X-ray fields were obtained by means of the product of air kerma (Kair) and the conversion coefficients (hp(3,ɑ)) recommended by ICRP116 recommendation. And these researches can be used by standard ionization chamber dosimeter. Finally, provided the conventional true value Hp(3) at calibrate point.Results:The standards and calibration program of calibrations eye-lens dose equivalent dosimeter were established under the X-ray radiation field. The detection error between slab phantom recommended by ISO and head phantom recommended by the 116th publication of ICRP was lower when the TLD was used to detect result.Conclusions:The standards for calibration Hp(3) dosimeters can satisfy the requirement of calibration for radiological occupational staff. It also provides theoretical foundation for detection data that assessed Hp(3) dosimeters and then improves trace ability and reliability of detection data of Hp(3) in national radiation supervision and inspection network.
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Objective To establish the methods for measuring the dose to occupational staff's eye lens in interventional procedures with direct-reading dosimeters,and to realize the real-time monitoring of eye lens dose and warning for high dose rate,thus providing the scientific basis of the staff radiological protection in interventional procedures.Methods Direct-reading dosimeters were calibrated with personal dose equivalent HP (3).The eye lens doses for occupational staff in different kinds of interventional procedures were measured by the devices with both single-and double X-ray tubes.The data obtained fromthe direct-reading dosimeters was compared to those obtained from TLDs.Results Direct-reading dosimeters showed good linear fitting with the calibration of HP (3),and the coefficients of variation were lower than 5％.The average eye lens HP (3) for the main operator in coronary arteriography and stent implantation in brain obtained by direct-reading dosimeters were 12.0 and 24.5 μSv,respectively,whereas those obtained by TLDs were 11.9 and 22.7 μSv,respectively.The direct-reading dosimeters gave similar t~nds as TLDs do so.The direct-reading dosimeters were able to provide eye lens HP (3) in each individual interventional procedure,and to monitor the real-time dose rate as well.Conclusions The calibration of HP (3) and the data gained by direct-reading dosimeters are reliable.Therefore,the methods for real-time measurement of eye lens dose for occupational staff in interventional procedures are successfully established.
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Objective To establish methods of measuring the eye lens dose to interventional staff,to obtain relevant dose data and to provide a scientific basis for reducing eye lens dose.Methods Two kinds of dosimeters,thermoluminescent dosimeter (TLD) and optically stimulated luminescence dosimeter (OSLD),were selected to measure the personal dose equivalent HP (3) to eye lens of occupational staff in several kinds of interventional procedures,including cardiovascular interventional procedures,cerebrovascular interventional procedures etc.Five types of Digital Subtraction Angiography (DSA) equipment were chosen in the study,including single tube equipment and double tube equipment.Results The eye lens dose HP (3) to interventional staff varied significantly with different interventional procedures.The lowest dose is shown in the coronary angiography procedure,while the highest dose shown in the cerebral stenting procedure.For the same type of interventional procedure,the eye lens dose to the primary interventionist was the highest.For same interventionist,the dose to the left eye was obviously higher than that to the right eye.In addition,the measured results of OSLD were apparently higher than that of TLD.Conclusions Both TLD and OSLD could be used to measure eye lens dose,and the ways of calibrating TLD to evaluate personal dose equivalent HP (3) were feasible.The reason of significant difference between the measured results of TLD and OSLD needs further research.
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Objective To establish the standard X/γ radiation fields with respect to the wrist dosimeter calibration curve as required by the international electrotechnial commission (IEC) technical specifications and the relevant national standard.Methods Air-kerma rate was determined in the X-ray beams,137Cs and 60Co radiation fields by a standard dosimeter.The wrist thermduminescent dosimetry (TLD) dosimeter was calibrated with personal dose equivalent values Hp (0.07) on the organization for standardization(ISO) wrist-phantom based on the radiation fields.Results The standard X/γ radiation field for the wrist dosimeter irradiation was established.Conclusions Established X/γ standard radiation field can be used for suc h technical services as wrist dosimeter calibration curve and energy response characteristics experiment.
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Objective:According to the technical standard of ISO and current regulations in China, the X/γ standard calibration quality for the finger-ring dosimeter irradiation was established in Beijing SSDL, it can ensure the traceability of surveillance data within countrywide.Methods: Air kerma-rate was determined in the X-ray beams,137Cs and60Co by a standard dosimeter, combined transfer coefficientHp(0.07) provided by standards, and confirmed condition of X/γ standard calibration quality for the finger-ring dosimeter irradiation. Using finger-ring TLD dosimeter verified the radiation beam qualities Hp on the ISO finger-phantom.Results: The linearity and energy response of the TLD dosimeter met ISO and national standard in Beijing SSDL.Conclusion: The X/γ standard radiation field can be used for the calibration of finger-ring dosimeter standard curves and experiment of research, and can further promote the comparability and reliability of the surveillance data.
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Objective:To complete experiments of the energy response compensation for three semiconductor personal dosimeters in order to meet the requirements of IEC and National Standard.Methods: In Beijing SSDL, the semiconductor detectors were covered by the different thicknesses of Pb and Sn additional filters with several diameter holes to compensate the dosimeters’ energy response.Results: At the 50 keV-Cs-137 energy range, the measuring error of dosimeters is met within 30% of energy response.Conclusion:By the compensation of combined Pb and Sn filters with a hole, the semiconductor personal dosimeters can be used for radiation monitoring.
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Objective:According to the requirement of ISO and National Standard, new X-ray environmental standard for the calibration of environmental dosimeter was established in Beijing SSDL. Methods:Half value layer and air kerma dose-rate was determined in the X-ray environmental qualities by a standard dosimeter. Results: The technical requirement of ISO and National Standard are met within 2% for the X-ray environmental standard qualities in Beijing SSDL. Conclusion:The X-ray standard radiation field can be used for the calibration of environmental dosimeters and experiment of research.