The presence of magnetic fields in a magnetic resonance accelerator (MR-linac) can affect the reference dosimetry, and thus the existing Code of Practices (CoPs) are inadequate for MR-linac. In this article, the characteristics of adsorbed dose to water and ionization chamber response in the presence of magnetic fields were introduced and a formalism for reference dosimetry in MR-linac was developed based on the existing CoPs, aiming to provide reference for dosimetric quality control and research work of MR-linac in China.

The presence of magnetic fields in a magnetic resonance accelerator (MR-linac) can affect the reference dosimetry, and thus the existing Code of Practices (CoPs) are inadequate for MR-linac. In this article, the characteristics of adsorbed dose to water and ionization chamber response in the presence of magnetic fields were introduced and a formalism for reference dosimetry in MR-linac was developed based on the existing CoPs, aiming to provide reference for dosimetric quality control and research work of MR-linac in China.

Objective To study the clinical significance of intercostobrachial nerve ( ICBN) reservation in radical resection of breast cancer .Methods 42 cases with breast cancer at stageⅠ,ⅡorⅢa were randomly divided into experimental group(n=28) and control group(n=14).In the experimental group,the ICBN were preserved in the axillary lymph node dissection operation ,while in the control group ,the ICBN were resected in the operation .After the operation,both two groups were treated as breast cancer and the patients were followed up .The operation time,the number of ALND , local tumor recurrence and distant metastasis rates after operation , survival rate were compared between the two groups.Results Postoperative 14 days,3 months and 6 months,the incidence rates of the sensory disorder in the internal upper arms in the control group were 85.7%,64.3% and 50.0% respectively,those in the experimental group were 10.7%,3.5% and 0.0%.The differences were statistically significant between the two groups(P<0.05).The average operation time,average number of lymph node dissection between control group and experimental group had no significant difference [(80.0 ±12.9) min vs (88.0 ±15.6) min,(16.4 ±5.4) vs (14.8 ±6.1)](P >0.05).In the control group,the local recurrence rate,distant metastasis rate and survival rate were 0.0%,7.0%and 0.0%,those in the experimental group were 0.0%,0.0% and 0.0%.There were no statistically significant differences between the two groups .Conclusion It is feasible to preserve the ICBN in radical resection of breast cancer ,which reserves the skin sensory function of the internal upper arm and axilla ,and enhance the patients'quality of life.

Objective To explore the effect of endovenous laser treatment ( EVLT) for varicose great saphe-nous veins complicated with ulcers .Methods 40 cases ( 46 limbs ) of varicose great saphenous veins complicated with ulcers underwent EVLT .The abnormal vein branches of the base of ulcers and adjacent ulcers were burned and closed.Results Except a case suffered the secondary transplantation for skin flap necrosis ,no infection,skin necro-sis,deep vein thrombosis complications occurred in other 39 cases.All the ulcers healed ,and postoperative lower limb varicose veins were disappeared .The operation time was (65 ±11.6) min.All the ulcers healed and the hospitalization time was (21 ±4.6)d.All the patients were followed up for 6-36 months,and no recurrence was found.Conclusion EVLT for varicos e great saphenous veins complicated with ulcers has the advantages of good effect ,minimal incision , and quick recovery .

Objective To study the expressions of programmed death 1 (PD-1) and programmed death ligand 1 (PD-L1) in liver injury of acute liver failure (ALF) in rats and the role of PD-1/ PD-L1 in liver inflammatory injury. Methods SD rats were divided into two groups: 6 in normal group and 30 in ALF model group. The ALF models in rats were induced by D-galactosamine (D-Gal). The sera and hepatic tissue samples were collected at 12, 24, 48, 72 and 120 hours after D-Gal injection. Expressions of PD-1 mRNA and PD-L1 mRNA in hepatic tissue samples were detected by reverse transcription-polymerase chain reaction (RT-PCR). Comparison of measurement data between groups was done by t test. Correlation test was performed using Pearson linear correlation analysis. Results The levels of alanine animotransferase (ALT) and aspartate animotransferase (AST) at 12 h of D-Gal injection were (217. 3±33. 7) U/L and (397. 2± 101.3) U/L, respectively,which were both significantly higher than those in normal group [(30. 5 ±3. 1) U/L and (78. 6±4.2) U/L, respectively; t=-8. 921 and -6. 121, respectively; both P＜0.01] and peaked at 48 h.The expression of PD-1 mRNA in model group at 12 h (0. 385±0. 074) was significantly higher than that in normal group (0. 097±0.009) (t= -7. 725, P＜0.01) , and peaked at 48 h (0. 927±0. 132),then decreased obviously at 72 h. The expression of PD-L1 mRNA in the liver tissue of normal rats was very little, while that in model group was increased gradually over time, then peaked at 48 h (0. 593±0. 105; t =- 10. 076, P＜0. 01). The expressions of PD-1 and PD-L1 were positively correlated with ALT level (r=0. 807 and 0. 792, respectively; both P＜0. 01). Conclusion The expressions of PD-1/PD-L1 may play an important role in liver inflammatory injury in rat model of acute liver failure.

Objective To investigate the effect of the operational treatment for periampullary carcinoma.Methods The data of 53 operative patients were retrospectively analyzed. Among the 24radical operations, PD was performed in 23 cases ,PPPD in 1 ;the palliative operation was performed in 29 cases. Results Among the 24 radical operaions, the overall mortality was 8.3% (2/24), no operational death. The postoperative morbidity was 15 cases,including 5 cases of pancreatic fistula. Median length of hospital stay was 26 days. Conclusion Continual improvement of operative technique and sufficient perioperative management were the keys to increasing the effect of the operational treatment.

Objective To investigate the influence of age on liver histopathological feature of patients infected with chronic hepatitis B. Methods Liver biopsies were performed on 114 patients with chronic hepatitis B. The biochemical tests were measured by routine automated techniques. Serum hepatitis markers including HBsAg, anti-HBs, HBeAg, anti-HBe, and anti-HBc were assayed by using a microparticle enzyme linked immunosorbent assay. HBV-DNA was measured with quantitative polymerase chain reaction assay. The grades of liver necrosis/inflammation and fibrosis were compared between four groups with different age: younger than 20years, 20 ～ 30, 31 ～40, and older than 40 years. Results All 114 patients had liver histological changes with different degree. 75.4 percent (89/114) of cases had 2/over 2 grades of liver necrosis/inflammation, and 47.4 percent (54/114) of cases had 2/over 2 stages of liver fibrosis.There was no significant relation between the level of ALT and age or between the level of ALT and the grades of liver necrosis/inflammation and fibrosis( P ＞0. 05 ). The significant difference in degrees of liver inflammation and fibrosis was found among three age groups ( x2 = 30. 86, P ＜ 0. 01; x2 = 21.17; P ＜0.05 ). The grades of 1 iver inflammation and fibrosis increased with the increased age of the patients. Conclusion These results suggested that age was an independent factor for the disease progression. It was very important to undertake liver biopsy for patients with CHB more than 30 years to reveal the liver histopathological characteristics and guide the treatment.

Objective To investigate the principles of diagnosis and treatment of early postoperative inflammatory small bowel obstruction(EPISBO).Methods The clinical data of 22 patients admitted to our hospital from January 2000 to June 2009 were analysed for early postoperative inflammatory small bowel obstruction.Results 22 cases were cured in a mean period of 15 days through gastrointestinal decompression,somatostatin,TPN and other medications.There was no reoperations.Conclusion For EPISBO,conservative treatment should be adopted first,somatostatin and TPN has batter results.