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 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 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 investigate the relationship between the serum homocysteine(Hcy) level and heart rate variability in elderly patients with metabolic syndrome.Methods Retrospective analysis of 162 elderly patients with metabolic syndrome aged 60 and above was conducted in our hospital from January 2013 to August 2016.And the level of serum homocysteine and other biochemical indicators were measured.The 162 cases were divided into three groups of 42 cases in Hcy normal group(Hcy,5-15 μmol/L),70 cases in Hcy mildly high group(Hcy,16-30 μmol/L),50 cases in Hcy moderately high group (Hcy,31 ～ 100 μmol/L).Simultaneously 24-hour rhythm in ambulatory heart rate variability spectrum was used to detect HRV.And the relationship between heart rate variability(HRV) and Hcy levels were analyzed.Results Normal RR interval standand deviation (SDNN),5 min mean heart rate standard deviation (SDANN),Edinburg index (PNN50),root mean square value of adjacent RR interval difference(RMMSD)were all lower in Hcy mildly high group and Hcy moderately high group than in the Hcy normal group (P＜0.05).Low-frequency(LF) and highfrequency(HF)were lower in Hcy mildly high group and Hcy moderately high group than in the Hcy normal group(P ＜ 0.05).Sympathetic-vagal balance indicators (LF/HF) were higher in Hcy mildly high group and Hcy moderately high group than in the Hcy normal group (P＜ 0.05).The HRV indexes were lower in Hcy high groups than in the Hcy normal group.Hcy was negatively correlated with SDANN,RMSSD,LF,HF,and LF/HF at night(r=-0.578、-0.651、-0.531、-0.662、-0.729,all P ＜ 0.01).Conclusions The elevated homocysteine level and metabolic syndromecombined with decreased HRV in the elderly patients suggest that cardiac autonomic nervous system might be injuried.Enhancing the detection of HRV and homocysteine level in elderly patients with MS is clinically useful for early detection of autonomic neuropathy.

Objective To develop a practical image acquisition strategy using intermittent breath?hold cone beam computed tomography (CBCT). Methods A breathing phantom was used to simulate the movement of tumor near the diaphragm during free breathing and breath hold and scanned by conventional breath?hold CBCT and type Ⅰ/Ⅱ intermittent breath?hold CBCT. In the conventional breath?hold CBCT, scan paused and free breathing occurred at the break of breath hold and free breathing was not included in the scan. In the intermittent breath?hold CBCT, one scan covered several breath holds separated by free breathing in a ratio of 3 vs1. Image quality and three?dimensional registration accuracy were quantitatively compared between conventional breath?hold CBCT and type Ⅰ/Ⅱ intermittent breath?hold CBCT. Comparison of image quality parameters between conventional breath?hold CBCT and intermittent breath?hold CBCT was made by paired t test. Results Motion artifacts arose in type I and Ⅱ intermittent breath?hold CBCT scans. There were no significant differences in the reconstructed pixel value or uniformity between intermittent breath?hold CBCT and conventional breath?hold CBCT ( P>0. 05, and P= 0. 02, 0. 53 ) . Compared with conventional breath?hold CBCT images, the signal?to?noise ratios of type I andⅡintermittent breath?hold CBCT images were reduced by 30% and 60%, respectively ( P<0. 05 ) . The registration error was up to 0 . 4 cm in the anterior?posterior direction and less than 0 . 1 cm in other directions . Conclusions The phantom study shows that intermittent breath?hold CBCT does not significantly reduce image quality or registration accuracy compared with conventional breath?hold CBCT. The feasibility of intermittent breath?hold CBCT in clinical application needs to be further validated among a large number of patients.