Objective:Using Monte Carlo simulation method to study the important dosimetric parameter output factor of the LUNA stereotactic body radiotherapy device. Methods:Following the manufacturer’s technical documentation to establish the LUNA stereotactic body radiotherapy device’s Monte Carlo model and after model validation. After referring to the output factor measurement’s detector provided by manufacturer, set the relevant parameters in Monte Carlo model at last, compare and analyze the difference of output factor which provided between by manufacturer and calculated by Monte Carlo simulation. Results:In the range of 3%deviation, under the different collimator of condition, output factors which provided by manufacturers and calculated by Monte Carlo are in good agreement, and the reasons for the difference are also analyzed. Conclusion:LUNA stereotactic body radiotherapy device’s output factors of Monte Carlo simulated research work provides reference and basis for the clinical use and quality control.

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.

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.

Objective To explore the method for measuring and calculating both absorbed dose and effective dose received in organ and tissues of occupational workers by using TLDs for the implantation of 125Ⅰ seed sources.Methods The experiments with 60Co γ-rays were carried out for the stability.A group of TLD chips was exposed to 125Ⅰ seed sources to establish standard dose curve for air kerma.During the 125Ⅰ seed implantation, the TLD chips were pasted to 13 locations like thyroid inside and outside the lead aprons worn by occupational workers to measure average absorbed dose and calculate the absorbed doses and effectives to organs and tissues.Results For 3 cases of prostate cancers with implantation of 125Ⅰ seeds, the worker's organs and tissues received the absorbed dose 0.02 -3.80 μ Gy and effective dose 0.06- 1.81 μSv outside lead aprons and the highest absorbed dose 2.35 μ Gy and effective 0.02 μSv inside lead aprons, respectively, with more than 65.9% of rays shielded.For 3 cases of brain cancers with implantation of 125Ⅰ seeds, the workers received the absorbed dose 0.23 - 11.31 μGy and effective dose 0.88 - 4.07 μSv outside lead aprons and the highest absorbed dose 2.22 μ Gy and effective dose 0.09 μSv inside lead aprons, respectively, with more than 54.5% of rays shielded.For 3 cases of lung cancers with implantation of 125Ⅰ seeds, the workers received the absorbed dose 0.03 - 14.78 μGy and effective dose 0.35 -7.59 μSv outside lead aprons and the highest absorbed dose 4.09 μGy and effective 0.22 μSv inside lead aprons, respectively, with more than 58.4% of rays shielded.For 2 cases of mediastinum cancers with implantation of 125Ⅰseeds, the workers received the absorbed dose 0.06 - 74.91 μGy and effective dose 0.83 - 17.96 μSv outside lead aprons and the highest absorbed dose 10.29 μGy and effective 0.5 μSv inside lead aprons, respectively, with more than 85% of rays shielded.For one case of ovary cancer with implantation of 125Ⅰ seeds, the worker received the absorbed dose 0.09 - 14.29 μGy and effective dose 2.40 - 4.50 μSv outside lead aprons and the highest absorbed dose 7.77 μGy and effective 0.12 μSv inside lead aprons, respectively, with more than 34% of rays shielded.For one case of eye cancer with implantation of 125Ⅰ seeds, the workers received the absorbed dose 2.2 -39.84 μGy and effective dose 4.48 - 10.06 μSv outside aprons and the highest absorbed dose 5.19 μGy and effective 0.16 μSv inside aprons, respectively, with more than 54.6 % of rays shielded.Conclusions The method of using TLDs to measure the doses to the occupational workers in the course of the implantation of 125Ⅰ seed sources is simple and easy to operate.It would be an effective approach to protecting medical workers in the case of brachytherapy.

Objective To facilitate activity measurement by using the thimble ionization chamber in hospitals,to obtain air kerma scatter correction factor of medical afterloading of 192Ir source by developing an available and convenient calculation method.Methods According to International Atomic Energy Agency (IAEA) 1079 Report to calculate the scatter correction factor of 192 Ir source,to measure air kenna of 192Ir source with and without lead shield using thimble ionization chamber.Simulation measurement conditions were used to calculate scatter correction factor of 192Ir source and comparison was made between experimental results and literature records.At the same time,the different ionization chamber models were simulated at different room sizes to obtain scattering correction factor of 192 Ir source.ResultsComparison was made between the simulation scatter correction factors of 192Ir source and experiment by the shadow shield,and the relative deviation was 0.8%.The deviation of the 192 Ir activity calculated according to the simulated scatter correction factor and measured by well type ionization chamber was 2.4%.By comparison between the calculated results by using two kinds of spherical ionization chamber and those ones deduced by IAEA 1079 Report,the relative deviations ranged within 0.3%-0.4%.Five different types of thimble ionization chamber and different room sizes were simulated and calculated by MC simulation,with the relative deviation within 3%.Conclusions Monte Carlo simulation method for calculating afterloading 192 Ir source's scatter correction factor is feasible,and this method is convenient for use in the thimble chamber for brachytherapy QA work in the hospital.

Objective To explore the possibility of heterogenous gene to express in juvenile Schistosoma japonicum and the application of electroporation in transformation of schistosomulae. Methods The plasmids of pEGFP-C1 were introduced into mechanically transformed schsitosomula with electroporation. The presence, transcription and translation of the transgene in electroporated schistosomula were confirmed by PCR, RT-PCR and Western blotting analysis respectively using the genomic DNA, total RNA and protein extracted and isolated from schistosomula cultured in vitro for 48 hours. Meanwhile, localization of EGFP within electroporated schistosomula was performed with confocal laser scanning microscope. Results 760 bp and 276 bp amplified products by PCR and RT-PCR were found coincident with the expected size and expression of EGFP gene in elctroporated schistosomula was confirmed by Western blotting. Fluorescence of EGFP was localized in tegument and subtegument of the electroporated schistosomula with confocal microscopy, especially in the anterior part of the worm. Conclusion The heterogenous gene of EGFP has been successfully introduced into juvenile S. japonicum by electroporation and the expression of transgene was confirmed with molecular and microscopical methods.

Objective To explore the measurement method of the treatment dose of the patient with Diode for photon beam in radiotherapy,and to validate the treatment dose by comparing with the treatment planning system (TPS).Methods Experiments of the reproducibility,dose rate dependence,non-linearity dose response,and calibration factor in 60Co γ and 6 MV X beams were carried out with Diode on the surface of solid phantom and in water phantom.According to the needs of clinic treatment,different conditions were chosen to observe the dose changes with the angle of incidence,energy response,distance of source to skin,field size,wedge angle,block and tray using ionization chamber and water phantom.The Diode was placed on the surface of the solid phantom to obtain the correction factors.The doses of the chest,abdomen,and head and neek were verified with the Alderson phantom and Diode.Diode doses of the pelvis,head and neck at 14 points on the patient were measured.Results The Diode was irradiated at the points of the Alderson phantom,such as AP,RL and LL of the pelvis,with and without wedges,RL and LL junction of the neck and chin,with and without mask,the maximum relative deviation of doses was within ± 3% between Diode and TPS.The Diode was placed in different locations on the patient,including chest,abdomen and head and neck.The relative maximum deviation of doses was within ±5% between Diode and TPS.Conclusions The Diode method is reliable for measuring the exposure doses of the patient in radiotherapy.

Objective To verify the reliability of dose parameters of radiotherapy under reference and non-reference conditions by using TLD.Methods Dose parameters were verified by using TLDs under reference and non-reference conditions,including the maximum dose in axel of 5 electron beams with energy of 9 MeV and the variations of dose by depth,source-skin distance,exposure field and 45° wedge for 10 photon beams with energy of 6 MV in 5 hospitals.Results The average relative deviation of 6 MV photon beam measured between TLDs and finger ionization chambers were 4.45％,within ± 7％ as required by IAEA.The average relative deviation of 9 MeV electron beam measured between TLDs and plane parallel chambers were 2.45％,within ± 5％ was required by IAEA.Conclusions Measuring dosimetric parameters by using TLDs under reference and non-reference conditions was reliable and feasible.

Objective To assess the influence of length of the alanine tract of forkhead box E1 (FOXE1) gene on genetic susceptibility to idiopathic premature ovarian failure (POF). Methods Totally 110 patients with idiopathic POF were recruited between February 2009 and December 2012 at the Affiliated Shenzhen City Maternity and Child Healthcare Hospital of Southern Medical University. Controls (n=110) were individuals with normal menstrual cycles, normal FSH concentrations. The polyalanine tract and flanking sequence of FOXE1 were screened using the multiplex ligation-dependent probe amplification (MLPA) technique and direct sequence technique. Results The most frequent of FOXE1 polyalanine stretch length was 14 residues in both groups. The length of FOXE1 polyalanine reported in this study varied from 12 to 16 alanines, and three variants of FOXE1-polyalanine length, containing 12, 14, or 16 alanine residues, and 5 different genotypes were identified. The most common genotypes were 14/14 homozygote, occurring with the frequency of 81.8% (90/110) in the POF group, while 96.4% (106/110) in control subjects, respectively. The incidence of 14/14 genotypes of FOXE1-polyalanine was significantly lower in patients with POF (χ2=119.730, P=0.001) in comparison to the controls. There were significantly higher frequencies of the 16/16 genotypes in cases with POF [10.0% (11/110) versus 0; χ2=3.403, P=0.001], as compared with the controls. The FOXE1 14 alanine allele was significantly less common in the POF patient group than the controls [84.5% (186/220) versus 98.2% (216/220); χ2=25.923, P=0.001]. The FOXE1 16 alanine allele was significantly more common in the POF patient group than the controls [12.7% (28/220) versus 1.8% (4/220); χ2=19.412, P=0.001]. Conclusions The polymorphism of the polyalanine tract of FOXE1 gene have a certain relevance for the genetic aetiology of idiopathic POF.