Objective: To explore the technical characteristics and short-term clinical efficacy of robotic-assisted intersphincteric resection (ISR) for patients with low rectal cancer. Methods: A retrospective cohort study was used. Inclusion criteria: (1) rigid colonoscopy showed lower margin of the tumor ≤5 cm from the anal verge; (2) preoperative rectal MRI or endorectal ultrasound revealed staging T1-2, or T3 patients receiving concurrent chemoradiotherapy; (3) patients less than 70 years old with good function of anal sphincter before surgery; (4) no synchronous multiple primary carcinoma, and no distant metastasis; (5) the method of operation was agreed by the patient. Exclusion criteria: (1) T4 stage tumors; (2) sphincter dysfunction before operation; (3) recurrent tumors; (4) lower edge of tumors beyond the dentate line; (5) death due to non-rectal cancer during follow-up and unsatisfactory follow-up data. The clinical data of 21 patients with low rectal cancer meeting inclusion criteria undergoing robotic-assisted ISR at our department from January 2015 to June 2018 were collected. Parameters during and after operation were observed. Anorectal manometry was performed at 3, 6, and 12 months after the operation, and anal function was evaluated at 3, 6, and 12 months after the closure of the stoma by Kirwan classification and Wexner fecal incontinence score. The key steps of the operation are as follows: according to the principle of total mesorectal excision, the robot continued to enter into the levator ani hiatusdistally, and dissectin the sphincter space; according to the scope of sphincter resection, ISRwas divided into partial ISR, subtotal ISR, and total ISR; subtotal and total ISR usually needed to be combined with transanal pathway. The reconstruction of digestive tract was performed by double stapler anastomosis under laparoscope orhand-sewnanastomosis under direct vision, and preventive ileostomy was completed in the right lower abdomen. Results: Of 21 patients, 13 were male and 8 were female with mean age of (57.5±16.3) years. All the patients successfully completed the operation without conversion to laparotomy. Fourteen cases (66.7%) adopted partial ISR through complete transabdominal approach, 6 cases (28.6%) adopted the subtotal ISR through combined transabdominal and transanal approachs, and 1 case (4.8%) adopted the total ISR through the combined transabdominal and transanal approachs. The total operation time was (213.1±56.3) minutes, including (27.3±5.4) minutes for mechanical arm installation and (175.7±51.6) minutes for robotic operation. The amount of intraoperative hemorrhage was (62.8±23.2) ml, and no blood transfusion was performed in any patient. All patients underwent prophylactic ileostomy, and the stoma was closed 3-6 months after the operation. Except one case of anastomotic leakage, all other stomas were closed successfully. The postoperative hospitalization time was (7.6±2.2) days, and time to fluid intake was (3.3±0.9) days. One case of anastomotic leakage, one case of anastomotic stenosis, one case of inflammatory external hemorrhoids and one case of urinary retention occurred after surgery,and all of them were cured by conservative treatment. The mean diameter of tumors was (2.9±1.2) cm, and the number of harvested lymph node was 12.8 ± 3.3. In the whole group, the circumcision margin was negative, the proximal margin was (12.2 ± 2.1) cm, the distal margin was (1.1 ± 0.4) with all negative, and the R0 resection rate was 100%. The results of anorectal manometry showed that the preoperative rest pressure, rectal maximum squeeze pressure, initial sensory volume and maximum tolerated volume were (45.19±8.46) mmHg, (128.18±18.80) mmHg, (44.33±10.11) ml and (119.00±19.28) ml, respectively;these parameters reduced significantly 3 months after operation and they were (23.44±5.54) mmHg, (93.72±12.15) mmHg, (17.72±5.32) ml and (70.44±10.9) ml, respectively. The differences were statistically significant (all P<0.001). The resting pressure and the rectal maximum squeeze pressure returned to preoperative levels 12 months after operation, which were (39.33±6.64) mmHg and (120.58±16.47) mmHg, respectively (both P>0.05), while the initial sensory volume and the maximum tolerated volume failed to reach the preoperative state, which were (30.67±7.45) ml and (92.25±10.32) ml, respectively (both P<0.05). The patients were followed up for (22.1±10.6) months without local recurrence and distant metastasis. Eighteen patients were evaluated for anal function: Kirwan classification was grade I for 6 cases, grade II for 7 cases, grade III for 4 cases, and grade IV for 1 case; Wexner incontinence score was 8.6±0.8; 14 cases had good defecation control. Conclusion The clinical efficacy of ISR with Da Vinci robot in the treatment of low rectal cancer is satisfactory.

Objective:To investigate the feasibility of transforming conventional medical accelerator to achieve ultra-high dose rate required to achieve Flash radiotherapy (Flash-RT), and to understand the physical properties of the Flash-RT beam.Methods:By transforming the Varian 23CX medical accelerator, the radiation average dose rate at the isocenter was not less than 40 Gy/s. The relevant physical measurement scheme was designed to accurately measure the actual radiation dose rate of different source skin distance (SSD) conditions, the percent depth dose (PDD) curve and the off-axis dose distribution of the beam.Results:The average dose rate of 9 MeV electron beam after the transformation was measured using the HD-V2 type film, the average dose rate of 3 s was 97.9 Gy/s, and the average dose rate of 6 s was 99.27 Gy/s. When the SSD was 100 cm, 80 cm and 60 cm, the average dose rate of 9 MeV electron beam after the transformation was 99.3 Gy/s, 168 Gy/s and 297.5 Gy/s, respectively. After the transformation, the R100 of the 9 MeV beam was 2.2 cm underwater, R50 was 3.87 cm underwater, the electron range Rp was 4.58 cm, and the maximum possible energy Ep,0 on the phantom surface was 9.28 MeV. These parameters were slightly higher than those of the conventional 9 MeV beam, manifested with slight increase in the surface dose and widening high dose flat area. The overall deposit dose distribution exhibited the highest central axis and the increase in dose declines from the axis distance. Under the condition that the field size was 20 cm×20 cm and the SSD was 100 cm, the FWHM of the vertical and horizontal off-axis dose distribution curves were 16.6 cm and 16.4 cm, respectively. Conclusion:By transforming conventional medical accelerator, the average dose rate of the beam at the isocycle meets the requirement of Flash-RT, and the average dose rate under the condition of 60 cm SSD is much higher than the requirement of at least 40 Gy/s for Flash-RT.

Objective:To compare the effects on DNA strand break induced by ultra-high dose rate (FLASH) electron beam and conventional irradiation, and investigate whether FLASH effect was correlated with a reduction of radiation response.Methods:Aqueous pBR322 plasmid was treated with FLASH (125 Gy/s) and conventional irradiation (0.05 Gy/s) under physioxia (4% O 2) and normoxia (21% O 2). Open circle DNA and linear DNA were detected by agarose gel electrophoresis, and the plasmid DNA damage was quantified with an established mathematical model to calculate the relative biological effect (RBE) of DNA damage. In some experiments, Samwirin A (SW) was applied to scavenge free radicals generated by ionizing radiation. Results:Under physioxia, the yields of DNA strand breakage induced by both FLASH and conventional irradiation had a dose-dependent manner. FLASH irradiation could significantly decrease radiation-induced linear DNA compared with conventional irradiation ( t=5.28, 5.79, 7.01, 7.66, P<0.05). However, when the aqueous plasmid was pretreated with SW, there was no difference of DNA strand breakage between FLASH and conventional irradiation ( P>0.05). Both of the yields of open circle DNA and linear DNA had no difference caused by FLASH and conventional radiotherapy at normoxia, but were significantly higher than those under physioxia. In addition, the yields of linear DNA and open circle DNA induced by FLASH irradiation per Gy were (2.78±0.03) and (1.85±0.17) times higher than those of conventional irradiation, respectively. Conclusions:FLASH irradiation attenuated radiation-induced DNA damage since a low production yield of free radical in comparison with conventional irradiation, and hence the FLASH effect was correlated with oxygen content.

As a method for local treatment, radiotherapy plays a key role in the management of tumors. In the past few decades, great progress has been made in radiotherapy technology, with improvements in conformity, homogeneity, and radiotherapy efficiency, and the results are encouraging. Nevertheless, the maximum tolerated dose of normal tissue has limited the further increase in radiotherapy dose in the tumor area. If radiation-induced toxicities can be reduced, a higher radiotherapy dose can be delivered to tumor tissue, so as to achieve a better treatment response. In recent years, the unique FLASH effect of ultra-high-dose-rate radiotherapy (FLASH-RT) is capable of maintaining a consistent tumor response whilst reducing radiation-induced toxicities in normal tissue, and therefore, FLASH-RT has become a research hotspot in the field of radiotherapy across the world. At present, some scholars tend to explain the FLASH effect using the theory of acute oxygen depletion, but the protective effect of FLASH-RT on normal tissue remains to be clarified. In addition, preliminary clinical studies have been conducted for FLASH-RT, and the results are promising. Based on existing evidence, this article elaborates on the research advances in FLASH-RT in the treatment of malignant tumor, so as to provide a reference for the translation and application of this new technique.

Objective To explore the application and significance of intraoperative laparoscopic ultrasound( IOUS) in robot-assisted laparoscopic hepatectomy . Methods From February 2015 to February 2017 ,135 patients undergoing liver resection with robotic approach were enrolled in the study . All data about demographic ,surgical procedure and postoperative course were collected prospectively and analyzed . IOUS was routinely performed in these patients . To assist the localization and resection of liver tumor ,a four steps IOUS protocol in robotic liver surgery was proposed ,including exploration ,verification ,guidance , and confirmation . If necessary ,intraoperative laparoscopic ultrasound guided microwave ablation of liver tumor to complete the treatment . Results A total of 11 additional lesions in 11 patients were detected in 135 patients ,7 patients accepted strategic surgical modification : 4 cases were enlarged resection ,and 3 cases were treated with microwave ablation . There were only 17 patients lost blood more than 1000 ml in all patients . No patient suffered from any single or multiple organ dysfunctions ,and there was no mortality observed . Conclusions IOUS is indispensable to understand lesions and vessels ,confirm the complete resection of the tumor in robot-assisted laparoscopic hepatectomy . It is also a necessary tool for the microwave ablation of liver tumor .

Objective To evaluate and explore the diagnostic value of focal liver lesion ( FLL) ( ≤2 cm) undetectable on conventional ultrasound by image fusion with contrast-enhanced ultrasound(CEUS) . Methods A total of 50 patients with 65 lesions( ≤2 cm) were enrolled . All lesions were undetectable on conventional ultrasound but showed clearly in CT/MRI images . Ultrasound-CT/MRI image fusion with CEUS was performed ,and the nodule detection rate and enhancement perfusion mode were analyzed . Results All the 50 patients were matched successfully ,56 lesions (86 .2% ) were detected by image fusion combined with CEUS ,among which 27 lesions (41 .5% ) were significantly different from surrounding parenchyma on conventional ultrasound , 54 lesions ( 83 .1% ) showed different enhancement from the surrounding parenchyma on CEUS . There were 46 lesions that were eventually diagnosed by surgical pathology or clinical comprehensive diagnosis . The diagnostic accuracy of image fusion with CEUS was 91 .3% (42/46) . According to different groups of MRI matching sequences ,the detection rates of T 2 sequence group and enhanced sequence group were 87 .5% (28/32) and 91 .3% (21/23) ,respectively ,there was no statistically significant difference between the two groups ( P ＝0 .686) . Conclusions CT/MRI image fusion combined with CEUS has high detection rate and diagnosis accuracy for small FLL undetectable on conventional ultrasound .

Objective To explore the clinical value of the Liver Imaging Report and Data System ( LI-RADS) with contrast enhanced ultrasound(CEUS) in the diagnosis of hepatocellular carcinoma ( HCC) . Methods From October 2012 to July 2018 , the CEUS data of patients at high risk for HCC were retrospectively analyzed . A total of 197 lesions in 178 patients were classified with reference to the 2017 version of CEUS LI-RADS classification standard . Diagnostic reference standard was surgical pathology . The relationship between the LI-RADS classification and the pathological diagnosis was evaluated . Results One hundred and ninety-seven lesions ,with an average size of ( 2 .9 ± 1 .6)cm ,were pathologically confirmed to be 170 HCC ( 86 .3% ) ,17 non-HCC malignant lesions ( 8 .6% ) ,and 10 liver benign lesions ( 5 .1% ) . There were 6 (3 .0% ) ,37(18 .8% ) ,134 (68 .0% ) and 20 (10 .2% ) lesions classified into LR-3 ,LR-4 ,LR-5 and LR-M category ,respectively . Positive predictive values of HCC in LR-3 ,LR-4 and LR-5 category were 16 .7% (1/6) ,89 .2% (33/37) ,97 .0% (130/134) ,respectively . LR-5 category had high positive predictive value of HCC( 97 .0% ) ,but low sensitivity ( 76 .5% ) . If LR-5 category combined with LR-4 category were diagnosed as HCC ,the diagnostic accuracy was significantly higher than that of LR-5 category ( 92 .4% vs 77 .7% ) ,and the difference was statistically significant ( P ＜ 0 .05 ) . 95 .0% ( 19/20 ) lesions of LR-M category were malignant ,of which 30 .0% ( 6/20 ) lesions were HCC . 76 .9% ( 10/13 ) of intrathecal cholangiocarcinoma was characterized by LR-M . Conclusions The LI-RADS classification of CEUS has high application value for diagnosis and differentiation of HCC .

To investigate the feasibility ,safety and clinical effect of No touch liver pedicle microwave ablation . Methods T he clinical data of 229 patients with hepatocellular carcinoma treated in the Department of Hepatology ,Wuhan Tongji Hospital from M ay 2014 to October 2016 were retrospectively analyzed . T he patients were divided into 3 groups .In group A ,82 patients underwent ultrasound‐guided No touch liver pedicle microwave ablation ,69 patients in group B were treated with anatomical hepatectomy ,and 78 patients in group C underwent traditional microwave ablation . T he preoperative basic data ,intraoperative data ( treatment time , intraoperative blood loss ) and postoperative data ( postoperative liver function indicators ,complications ,hospitalization time ,local recurrence ,survival rate) were compared among the 3 groups . Results T he treatment time ,intraoperative blood loss ,postoperative liver function index and hospitalization time in group A and group C were significantly lower than those in group B( all P ＝0 .000) . T here was no difference in complete elimination rate ,between the two groups in group A and group B( P ＞0 .05) ,which was significantly better than those of group C ( P ＝ 0 .019 ) . T here was no significant difference in the local recurrence rate between the three groups after 1 year and 3 years . Conclusions No touch liver pedicle microwave ablation damage is safe and reliable ,in line with the principle of oncology treatment ,it worthes further promotion in the clinic .

To investigate the safety and feasibility of indocyanine green ( ICG ) fluorescence staining guided by laparoscopic ultrasound guiding portal branch puncture approach in anatomical segmentectomy of the liver . Methods The clinical data of 22 patients with malignant liver diseases underwent anatomical segmentectomy between February 2018 and M ay 2018 were retrospectively analyzed . ICG 0 .125～0 .250 mg was directly injected into the portal branches supplying blood flow to the tumor‐bearing hepatic segment , after puncturing of the target portal branch under intraoperative laparoscopic ultrasound guidance in all patients . T he fluorescence imaging system ( Pinpoint) was used for the resection procedure . Observation indicators :intraoperative conditions ( tumor diameter ,success rate of portal branches puncture ,success rate of staining the target hepatic segment ,intraoperative complications , time of operation ,volume of intraoperative blood loss , blood transfusion , and transit of laparotomy ) . Postoperative conditions :postoperative complications ,and length of hospital stay . Results Twenty‐two patients with liver tumors were all performed anatomical hepatectomy assisted by laparoscopic ultrasound guiding ICG injection for liver segment staining . All the liver tumors were hepatocellular carcinoma . ①Intraoperative conditions : T he portal branches puncture successful rate was 100% ( 22/22 ) . Eighteen patients achieved expected effect of ICG fluorescence staining ,with a satisfaction rate of 81 .8% (18/22) and 4 failed to get expected effect ,including 2 with uneven dying ,and 2 with adjacent hepatic segmental staining induced to unclear boundary . No complication such as allergy occurred in all patients after ICG injection . T he mean operation time was ( 209 ± 89 ) min ( range :97 ～ 325 min) and the target portal branches ICG puncture injection time under intraoperative laparoscopic ultrasound guidance was ( 11 ± 5) min ( range 3－25 min) . T here was no intraoperative blood transfusion or transit of laparotomy .Average tumor diameter was ( 3 .9 ± 1 .3) cm( range :2 .2－7 .0 cm ) . ②Postoperative conditions of 22 patients ,4 with grade Ⅰ － Ⅱ of Clavien‐Dindo classification were improved by drug treatments ( 1 with deep venous thrombosis of the lower extremities and 3 with pleural effusion ) , no patient had grade Ⅲ and above complications , and no perioperative death occurred . Average duration of hospital stay was ( 7 ± 2 ) days in 22 patients ( range :5 .0－14 .0 days) . Conclusions ICG fluorescence staining guided by laparoscopic ultrasound guiding portal branch puncture ,obtains accurate and lasting fluorescence markers on the liver surface and inside the parenchyma . ICG staining guides the selection of liver section in the operation of liver in real time ,and helps surgeons to perform laparoscopic anatomical segmentectomy of the liver .

Objective To evaluate the imaging features of nigrosome-1 in Parkinson's disease (PD) with a 3 T scanner by susceptibility weighted imaging (SWI),and to explore its clinical relevance.Methods Thirty-two patients with primary PD diagnosed by neurologists were collected.Healthy controls matched to their age and gender were recruited during the same period (n=20).All subjects underwent routine brain magnetic resonance imaging (MRI) and sensitive weighted imaging (SWI).The SWI images of the subjects were evaluated to evaluate nigrosome-1 by blinded investigators.Then,the correlation between imaging features and clinical data was analyzed.Results In the PD group,21 cases of bilateral "absent swallow-tail sign",five cases of bilateral "indecisive swallow-tail sign",five cases of "absent swallow-tail sign" on one side and "indecisive swallow-tail sign" on the other side,and one case of bilateral "clear swallow-tail sign" were found.The course of the "absent swallow-tail sign" group (56 (54) months) was significantly longer than the "non-absent swallow-tail sign" group (18 (18) months;U=-2.47,P=0.01).The Hoehn-Yahr stage was significantly higher in the "absent swallow-tail sign" group (2.0 (0.5)) than in the "non-absent swallow-tail sign" group (1.5 (0.5),U=-2.21,P=0.03).There was also a statistically significant difference in the Unified Parkinson's Disease Rating Scale score (24 (8),13 (14)) between the two groups (U=-2.91,P=0.01).However,there were no statistically significant differences between the two groups in the Hamilton Depression Scale score (5 (2) vs 5 (7),U=-0.10,P=0.94) and the Hamilton Anxiety Scale score (3.0 (2.5) vs 3.0 (3.0),U=-0.02,P=1.00).Conclusion The images of nigrosome-1 by SWI are closely related to the severity of the condition and motor symptoms of patients with PD,which can reflect the severity of the disease.