The purpose of the experiment was to investigate the changes of malondialdehyde (MDA) level and morphological changes in ventricular myoeardium in burnt rats. The results showed that the pathological changes of ventricular myocardium were characterized by its being presented early, severity and multiple patterns; the pathological changes underwent a dynamic course, which could be roughly divided into three phases: the early phase, aggravative phaes and recovery phase of the injury; oxygen-derived free radicies might be a participant in injuring ventricular myocardium according to the experiment.

Background and purpose:There is controversial about dissecting the laryngeal nerve in operation of thyroid tumour in clinic. We adopted the methods of exposure of recurrent laryngeal nerve(RLN) to study their deficiencies and benefits. Methods:We reviewed review 456 cases of thyroid tumour who were operated. In 266 cases, RLN was unveiled generally. In 190 cases that RLN was not exposed, had subtotal thyroidectomy with protection of amatomical region.Results:RLN injury did not occur in the exposure group. 4 cases occurred in non-exposure group(3 cases of temporary RLN injury and 1 case of permanent RLN injury). Among the 3 cases of temporary RLN injury, one was caused by the large size of tumour, the other two were caused by the location of thyroid tumor. One case of permanent RLN injury was a case of reoperation for recurrence.Conclusions:The familiarity of the anatomy and variation of RLN, and the exposure of RLN in thyroid operation, can reduce the rate of the RLN injury.

Background and purpose:Indensity modulated radiotherapy(IMRT) is an advanced method in radiotherapy field.Divect machine optimization technique is an good aritmetic for IMRT optimization.The purpose of this study was to compare the dosimetric differences between traditional technique and direct machine parameter optimization(DMPO) technique in the treatment of nasopharyngeal carcinoma(NPC) using step and shoot IMRT.Methods:Eleven patients of(NPC) were treated with step and shoot IMRT in Cancer Hospital,Fudan University from Feb.2005 to May 2006.Their plans(original plan,defined as treat) were archived for comparing with four kinds of IMRT plans(defined as DMPO100,DMPO90,DMPO80,DMPO70) with different predefined maximum number of segments(100,90,80,70,respectively),which were designed to use direct machine parameter optimization(DMPO) technique.We compared the total monitor units(MU),total segments,dose distribution and conformity index among the plans.Results:All the plans showed similar target coverage.Compared with traditional technique,IMRT plans with DMPO technique showed higher conformity index,and had similar uniformity except plan DMPO70.The dose distributions of DMPO100 and DMPO90 were similar or superior to the original plan(treat) in terms of critical organs.Without sacrificing plan quality,the total segments were about half of traditional plan if DMPO technique was used for planning.Moreover,the total monitor units(MUs) and the radiation time were decreased.Conclusions:Compared with traditional technique,plans designed with DMPO technique show sharp decrease in total segments without sacrificing plans quality in the treatment of nasopharyngeal carcinoma(NPC).The DMPO technique can also decrease the total MUs and radiation time.

Objective To develop an automatic algorithm to predict the dose-volume histogram (DVH) and implement it in clinical practice.Methods Based on the prior information in the existing plan,such as dosimetric results of organs at risk (OARs) and OAR-target spatial relationship,a two-dimensional kernel density estimation was implemented to predict the DVH of OARs.The predicted DVH curves were converted into objective functions that would be implemented in the Pinnacle treatment planning system.Comparisons between predicted and actual values and between Auto-plan and manual planning were made by paired t test.Results We applied this algorithm to 10 rectal cancer patients,10 breast cancer patients,and 10 nasopharyngeal carcinoma patients.The predicted DVH of OARs showed that the deviation between the actual and predicted values at important clinical dose points were within 5%(P>0.05).The re-planning for the 10 breast cancer patients using Auto-plan showed that the heart dose was significantly reduced and the target coverage was increased,which was consistent with the predicted results.Conclusions The method proposed in this study allows for accurat DVH prediction,and,combined with Auto-plan,can be used to generate clinically accepted treatment plans.

Radiomics is a new area of research, which converts imaging data into high?resolution quantitative imaging features by applying the automatic high?throughput imaging?feature?extraction algorithm. With the development of data science, more and more attention has been paid to the non?invasive and quantitative method in precision radiotherapy all over the world. This paper will briefly introduce the concept of radiomics and its application in precision radiotherapy.

Background and purpose: Currently, intraoperative radiation therapy (IORT) has become the adjuvant therapy of cancer. The study was to establish the daily quality assurance (QA) program and analyze dosimetric characteristics’ long-term stability for mobile IORT accelerator. Methods:The QA program of this study included two parts:safety and functionality and energy and output. The two years’ QA datasets were acquired and analyzed to investigate the stability of energy and output. Results:All safety and functionality tests passed on a daily basis. The energy index was (0.666±0.015)mm, (0.839±0.009)mm, (0.781±0.010)mm, (0.724±0.009)mm and the output dose error was (0.511 ± 0.671)%, (0.278 ± 0.516)%, (0.368 ± 0.532)%, (0.382 ± 0.912)%for all energy, respectively. There was no signiifcant time trend in the dosimetric characteristics. Conclusion:The daily QA program is suitable for mobile IORT accelerator. The long-term stability is acceptable for IORT in clinical use.

Objective To investigate the accuracy of image registration with computed tomograpby (CT) and magnetic resonance imaging(MRI) and to determine gross tumor volume(GTV) of hepatocellular carcinoma(HCC).Methods Thirteen patients were enrolled in this study.CT image was taken in inhala tion phase,and MRIT2 image at the time of peak exhalation.Additional MRIT2 image was taken by fast scanning(MRIT2F) in peak inhalation phase in 6 patients.After mutual information method to CT/MRI im age registration,manual adjustment was made to optimize the accuracy of image fusion.The GTV and liver of each patient was independently contoured by two observers on CT,MRIT2 and MRIT2F images.The accura oy of image fusion was assessed by the ratio of liver overlap(P-LIVERCT-MRIAT2 ,P-LIVERCT-MRIT2F) ,and the dis tance between bone markers(DCT-MRIT2,DCT-MRIT2F) of CT and MRI on the fused image.The volumes of GTV contoured on CT (V-GTVCT),MRIT2 (V-GTVMRIT2),MRIT2F (V-GTVMRIT2F) and their overlap (V GTVCT-MRIT2,V-GTVCT-MRIT2F) and composite volumes (V-GTVCT+MRIT2,V-GTVCT+MRIT2F)were measured.The percentage of V-GTVCT and V-GTVMRIT2 on V-GTVCT+MRIT2,V-GTVCT and V-GTVMRIT2F on V-GTVCT+MRIT2F,V GTVCTMRIT2 and V-GTVCT-MRIT2F on V-GTVCT was also calculated,respectively.Results The mean DCT-MRIT2 and DCT-MRIT2F were 2.7±0.8 mm and 2.1Q±0.9mm.The mean P-LIVERCT-MRIT2 and P-LIVERCT-MRIT2F were 85.9% ± 4.1% and 92.7%± 1.5%.Interobserver difference was significant for GIN defined by CT,but not by MRIT2.V-GTVCT,V-GTVMRIT2 and V-GTVMRIT2F were 387±396 cm3 ,488 ±461 cm3 and 597 ±541 cm3 ,respectively.The percentage of V-GTVCT and V-GTVMRIT2 on V-GTVCT+MRIT2 was 66.2%±13.5% and 88.7% ± 10.2% ,while V-GTVCT and V-GTVMRIT2F on V-GTVCT-MRIT2F was 71.3%±12.7% and 93.5%± 4.8%,respectively.Conclusions CT and MRI for image fusion should be obtained in the same respirato ry phase and in the same treatment position.Automatic registration using mutual information method by auto matic registration software is useful.CT and MRI image should be integrated for HCC GTV delineation.GTV used for planning should be the sum of CT-defined GTV and MRl-defined GTV.

Objective To quantitatively evaluate the image quality, stability and volume precision in kilovoltage cone beam CT (CBCT) on Varian linear accelerator. Methods The Catphan (R) 600 phantom was repeatedly scanned in the full-fan and half-fan CBCT scanning modes. A simulation fan-beam CT (FBCT) was used as a benchmark and results related to the low contrast resolution, spatial resolution,uniformity and image noise were compared with the CBCT using the treatment planning system. The comparison of image quality and long-term stability and volume precision was analyzed. Results Spatial resolution was no differences observed between FBCT and CBCT ( 6 lp/cm: 6 lp/cm , T = 18. 00 , P＞ 0. 05 ) .Low contrast resolution was, on average, 1. 65％ and 1. 74％ for both CBCTFull-Fan and CBCTHalf-Fan , and 1. 03％ for the FBCT ( T =6. 00, P ＜ 0. 05). Uniformity was, on average, 0. 005 and 0. 033 for both, and 0. 003 for the FBCT ( T=6. 00 , P ＜0. 05). In terms of image noise, the FBCT images were superior to the CBCT (T=30. 00, P＜O. 05). In valid scan range of the CBCT, reconstructed precision was high. There was no significant time trend in the image quality. Conclusions The image quality of kilovoltage CBCT is inferior to the conventional CT. However, tumor and soft tissues are visible in the CBCT images. The image stability and reconstructed precision is satisfying.

Objective To observe the effect of the occupational therapy (OT) on people with mental disability in community of Beijing and analyze its related factors. Methods 180 mentally disabled persons from 15 disabled persons' centers (DPCs) in a district of Beijing were studied with a self-developed questionnaire. They were investigated twice with a 6-month interval, and the results were compared. Results 160 questionnaires were valid for analysis. The score of OT improved (P<0.05) in 103 (64.38%) respondents. The main factors related with the effectiveness of the OT included OT categories, age and vocational assessment. Conclusion OT is effective on people with mental disability in the DPCs, and could be improved in some aspects, such as regular vocational assessment.

Charged particle therapy offers a better effect and obvious dosimetric and biological advantages over conventional radiotherapy in tumor control.Charged particles form Bragg peak in the dose distribution in tissue, enable most of energy to be deposited in the target region, and thus enhance tumor control and reduce the damage to normal tissues surrounding the tumor.With the increasing demand for charged particle therapy and the advances in particle accelerator, particle therapy technology is developing rapidly.The core apparatus of particle therapy facility is particle accelerator, and the accelerator type, particle type, and implementation technique determine the performance and therapeutic effect of the facility.This article provides a detailed comparative analysis of various particle therapies.Statistical data show that proton therapy is dominant in particle therapy, and high construction difficulty, large facility size, and extremely high cost have limited the development of heavy ion therapy.Nowadays, there are still some technical problems regarding charged particle therapy, and more clinical trials are required.