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.

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.

Objective To put forward reasonable and feasible recommendations against the procedure with relative high risk during the high dose rate (HDR) afterloading radiotherapy,so as to enhance its clinical application safety,through studying the human reliability in the process of carrying out the HDR afterloading radiotherapy.Methods Basic data were collected by on-site investigation and process analysis as well as expert evaluation.Failure mode,effect and criticality analysis (FMECA) employed to study the human reliability in the execution of HDR afierloading radiotherapy.Results The FMECA model of human reliability for HDR afterloading radiotherapy was established,through which 25 procedures with relative high risk index were found,accounting for 14.1％ of total 177 procedures.Conclusions FMECA method in human reliability study for HDR afterloading radiotherapy is feasible.The countermeasures are put forward to reduce the human error,so as to provide important basis for enhancing clinical application safety of HDR afterloading radiotherapy.

Objective To put forward reasonable and feasible recommendations aiming at enhancing the application safety of afterloading unit, through studying the human reliability in the emergency response against the source blockage of afterloading unit.Methods Based on the human cognition reliability model, ten operation errors during the emergency response against the source blockage of afterloading unit were analyzed and permissible time widow of emergency response operation were determined.The human error probability was calculated with the execution time of emergency response operation obtained through simulation, observation and recording.Results The operation action, relevant permissible time window and execution time were obtained with the corresponding human error probabilities in the range 0.04 - 0.27.Conclusions The human error model in emergency response against the source blockage of afterloading unit based on HCRmodel is feasible, and provides important reference basis to reduce the occurrence of potential exposure and mitigate the consequence of potential exposure.

Postgraduate students make an important contribution to scientific research work,and they are also important for discipline development,scientific research subject verification and talents cultivation.Besides,the problems existing in postgraduate training are analysed,which further expounded the role postgraduate training in the overall research potential of the institute.

Objectives To investigate the clinical and pathological characters , treatment of patients with Angioimmunoblastic T cell lymphoma(AITL). Methods From 1997 to 2004, 14 patients with AITL were reviewed retrospectively in our hospital. Results The most common symptoms at the presentation included general lymphadenopathy. 9 patients had fever. 3 patients had autoimmune hemolytic anemia.The histopathologic characteristics of AITL was generalized as:the damage of normal structure of lymphonodus,the proliferation of immunoblastic cell and arborescent supervascularization. All immunophenotyping were T cell type.14 patients were with ProMACE-CytaBOM regimen.The overall response rate was 57% and CR 3 cases, PR 5 cases. Median survival times was 25 months. 2-year survival was 60 %. Conclusions The most cases with AITL runs an aggressive course.The disease may progress rapidly and have unfavorable prognosis. Therefore further studies are repuired to improve the outcome.

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.

Objective To investigate the efficacy of endovascular stenting for aortic arch artery stenosis after nasopharyngeal carcinoma radiotherapy. Methods The clinical data of 8 patients with symptomatic severe aortic arch artery stenosis after nasopharyngeal carcinoma radiotherapy were analyzed retrospectively. The patients were all received endovascular stenting,and their improvement of cerebral ischemic symptoms was observed. They were followed up by cervical color Doppler ultrasound.Results The whole brain vascular DSA confirmed that there were 24 severe arterial stenoses on the aortic arch arteries of extracranial segments in 8 patients,including 11 in internal carotid artery,2 in common carotid artery,10 in vertebral artery and 1 in subclavian artery. The patients were treated with vascular angioplasty and stenting respectively. All the patients were followed up for 1 year;there were no recurrence of cerebral ischemic symptoms.Cervical color Doppler ultrasound did not reveal any obvious restenosis. Conclusion Endovascular stent angioplasty for the treatment of aortic arch artery stenosis after nasopharyngeal carcinoma radiotherapy is relatively safe and feasible.

Objective To identify the steps with potentially higher risk through the analysis of human factors in clinical PET application so as to provide the efficient measures to reduce the risk of potential exposures.Methods The basic data were obtained through field investigation, questionnaire,failure mode, risk identification, FMECA and expert's evaluation, with statistical analysis made.Comparison was made of the relative risk values of automatic encapsulation equipment and manual encapsulation ones.Results The 10 steps with potentially higher risks were identified through analyzing human factors of clinical PET application, of which 8 occurred in the phase of chemical synthesis.The measures to control risk were addressed for the steps with higher risk.The results show that the relative risk value of the clinical process with automatic encapsulation equipment was 2.28 ± 0.99 and the one with manual encapsulation equipment was 3.20 ± 2.01 ( t = 2.56, P ＜ 0.05 ), with the latter being 76% of the former.Conclusions Failure mode and FMECA are effective in risk evaluation of clinical PET application, which can provide important basis for risk control.