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.

This study was aimed to observe the protective effect of extract from Rhizoma A nemones Raddeanae (RAR) on hepatic fibrosis induced by porcine serum in rats. A total of 68 SD rats were randomly divided into 5 groups, which were the normal group, model group, RAR group, extraction of RAR (EXRAR) group, Fu-Zheng Hua-Y u(FZHY) group. Each rat was intraperitoneally injected with 0.5~0.6 ml of porcine serum twice a week for 15 suc-cessive weeks to establish liver fibrosis model. Intragastric administration was given after the model was successfully established. The FZHY group was given FZHY capsule (0.525 g·kg-1). The RAR group was given RAR decoction (0.7 g·kg-1). The EXRAR group was given EXRAR (0.071 g·kg-1). The model group and normal group were given e-qual amount of physiological saline. The medication was given once a day. And the treatment course was 8 weeks. At the end of the 23th week, rats were sacrificed. Contents of SOD and MDA in blood serum were assayed. The protein expressions of α-SMA and TGF-β1 in liver tissues were detected by SABC. The results showed that compared with the model group, content of MDA decreased in the EXRAR group, RAR group and FZHY group (P<0.05), and content of SOD increased obviously (P<0.05). In the model group, expression of α-SMA and TGF-β1 increased, with dark brown dyeing and diffusion area. Expression area and strength of the FZHY group, RAR group, and EXRAR group were ob-viously weak with tasteless interval dyeing and no formation of typical pseudolobule in comparison with the model group. The color rendering index showed that compared with the model group, the protein expression of α-SMA and TGF-β1 decreased obviously in liver tissues of the FZHY group, EXRAR group, and RAR group (P< 0.05). It was concluded that RAR and its extract had a good antifibrosis effect. And the EXRAR had basically the same antifibrosis effect as RAR. It was assumed that the possible mechanism was related with the inhibiting of hepatic stellate cell (HSC) activation and the expression of TGF-β1 as well as the resisting of lipid peroxidation.

OBJECTIVE To analyze for mutations of the PDS gene in patients with sensorineural hearing loss associated with enlarged vestibular aqueduct and analyze the molecular pathogenesis of enlarged vestibular aqueducts. METHODS Eighteen sporadic cases of large vestibular aqueduct syndrome and twelve control individuals with normal hearing were included in this study. Exons 6 and 9 of the PDS gene in all subjects were amplified by polymerase chain reaction and analyzed by direct DNA sequencing. RESULTS Analysis revealed 2 single base changes in exon 6 of one patient with large vestibular aqueduct syndrome. One was a G→C transversion at nucleotide position 611, and the other was a T→G transversion at nucleotide position 612, resulting in a predicted Gly→Ala substitution at position 204. No mutation in exons 6 and 9 of the PDS gene was found in the PDS gene of the control individuals. CONCLUSION Mutations of the PDS gene are responsible for the large vestibular aqueduct syndrome. Analysis of the PDS leftover sequence in patients with large vestibular aqueduct syndrome is the next step in elucidating the complicated causes of this disease.

OBJECTIVE Congenital aural atresia repair is difficult owing to unpredictable anatomy. Benefits may be gained from image-guided surgery(IGS) . its exact role and surgery indication were def ined. METHODS From 2001 to 2004,36 ears with bony type C(Schuknecht classification) congenital atresia were performed. In the IGS group(n=18) ,repair surgery was performed with IGS,while in the control group(Non-IGS,n=18) ,similar intervention was applied without IGS. IGS group:aged from 12-29 years,follow-up from 6 months to 1 year. Non-IGS group:aged from 10-27 years,follow-up from 6 months to 3 years. Intra-and post-operative clinical and audiometric findings were compared. RESULTS All of the patients had congenital bony aural atresia,ossicles malformation,tympanic cavity hypoplasia and facial nerve malformation. IGS revealed a malformed horizontal semicircular canal hidden in the bony atresia plate during the operation while computed tomography(CT) did not show preoperatively. IGS computed tomography images correlated well with intra-operative findings,gave the surgeon more securityand reduced operative time(2 hours and 24 minutes) by 25 minutes. The prepare time increased 20 minutes(15-30 minutes) ,but total time decreased 5 minutes in IGS group. The registration accuracy was 0.6-1.3 mm,average 0.84 mm,which was suitable for the otologic surgery. There were 1 case in IGS group and 3 cases in Non-IGS group happened local aural restenosis after operation. But there were no facial nerve paralysis and hearing injury happened in both groups,and all of the patients got the satisfactory hearing after the hearing reconstruction(the air-bone gap with an average of IGS is 31.8dB,Non-IGS is 30.5dB) . CONCLUSION In our estimation,IGS is valuable for type C congenital aural atresia repair. It serves as an educational tool and a guide both for the experienced and inexperienced surgeons in critical situations where anatomical landmarks are distorted and approach is limited. There is no statistically significant between two groups on hearing improvement after operation.

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.

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.