Objective To evaluate the peripheral dose (PD) from megavoltage cone-beam CT (MVCBCT) imaging for head-and-neck region image-guided radiation therapy,to determine the correlation of PD with monitor unit (MU),and to investigate the impact of imaging field size on the PD.Methods Measurements of PD from MVCBCT were made with a 0.65 cm3 ionization chamber placed in a specially designed phantom at various depths and distances from the field edges.The PD at reference point inside the phantom was measured with the same ionization chamber to investigate the linearity between MU used for MVCBCT and the PD.The homogeneity of PD in the axial plane of the phantom were measured.Results PD from MVCBCT increased with increasing number of MU used for imaging and with increasing the field size.The measured PD in the phantom decreased exponentially as distance from the field edges increased.PD also decreased as the depth from the phantom surface increased.There was a strong linear relationship between PD and MUs used for MVCBCT.The PD was heterogeneous,with higher dose at the anterior than the posterior.Conclusions The PD from MVCBCT depend much on the MVCBCT delivery MU and the scan field size.In clinic,using the smallest number of MU allowable and reducing MVCBCT scanning field size without compromising acquired image quality is an effective method of reducing the PD.

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Objective To compare the whole-body equivalent doses from volumetric modulated arc therapy (VMAT) and static intensity-modulated radiotherapy (IMRT) for patients with cervical cancer.Methods Nine patients with cervical cancer admitted to our hospital in 2014 were included in this study.Both VMAT and IMRT were planned for each patient.Each patient's personal dose equivalent (Hp (10)) was measured using thermoluminescent dosimeters placed at the xiphoid process and glabella during IMRT and VMAT.The whole-body equivalent doses were estimated based on the results measured at the xiphoid process and compared between the VMAT and IMRT techniques.The paired t test was used for difference analysis.Results The Hp (10) values measured at the xiphoid process and glabella of every patient were lower for VMAT than for IMRT.At a prescribed dose of 50 Gy,if the mean Hp (10) values measured at the xiphoid process were considered to represent the whole-body equivalent doses,the whole-body equivalent doses for VMAT and IMRT were 364 mSv and 538 mSv,respectively.Conclusions VMAT results in a lower whole-body equivalent dose to patients compared with IMRT.The decreased whole-body equivalent dose delivered by VMAT may reduce the likelihood of a radiation-induced secondary malignancy.

Objective To compare the clinical outcome of internal fixation(IF)and total hip arthroplasty (THA)for the elderly patients with displaced femoral neck fracture. Methods A total of 128 patients with dis-placed femoral neck fracture admitted from January 2010 to December 2012 were selected and divided into IF group(61 cases)and THA group(67 cases). The operation and hospitalization index were compared between the 2 groups. All patients underwent follow-ups after operation. The functional recovery scale for hip fracture (FRS) and EQ-5D index were applied to evaluate the clinical outcomes periodically. Results Compared to THA group, the intraoperative trauma ,operation time and bed days were less in IF group(P<0.05),however the incidence of complication in IF group was higher than that in THA group. All the patients were followed up more than 3 years and mortality rate between the 2 groups showed no significant difference(P>0.05). Follow-ups at all time points revealed hip function in THE group is better than that in IF group(P<0.05),while no significant difference was found in terms of life quality(P > 0.05). Within 3 years,the costs related to fracture were 41772 yuan for IF group and 61174 yuan for THA group respectively. Conclusion Both internal fixation and total hip arthroplasty can provide satisfactory outcome for elderly patients with displaced femoral neck fracture. Compared with IF ,THA causes bigger trauma and costs more ,but ends up with lower complication incidences ,and improve hip function in a shorter period.

Objective To investigate the clinical efficacy of microendoscopic discectomy(MED) and fanestration discectomy (FD) for treating single segement lumbar disc herniation(LDH).Methods A total of 168 patients with single segment LDH were included in this retrospective study from April 2009 to Janurary 2012.The patients were divided into MED group(81 cases) and FD group(87 cases) according to surgery mode.The operation and hospitalization indexes for each group were collected and compared respectively.The clinical outcomes were evaluated by the visual analogue scale(VAS),Japanese Orthopedic Association(JOA) scores and Oswestry Disability Index(ODD.Lumbar curves(Cobb's angle),intervertebral space height,horizontal displacement and angular displacement before and after surgery were applied to evaluate the lumbar spinal stability.Results The skin incision length,amount of intraoperative blood loss,operation time and hospitalization duration in the MED group were less than that in the FD group(P＜0.05).All cases completed follow up for more than 4 years.The each item score at last follow up in the two groups was significantly improved compared with before operation(P＜0.05),the inter-group comparison had no statistical difference(P＞0.05).The postoperative lumbar curve and intervertebral space height were decreased in both groups.The postoperative lumbar curve in the FD group was decreased compared with the MED.One case in the MED group and 3 cases in the FD group appeared lumbar vertebral instability.Conclusion Both MED and FD for treating single segment LDH can gain better clinical effect,MED has short operation time,small trauma and little influence on lumbar vertebral stability,and is an effective minimal invasive surgery.

Objective Hepatic artery (HA) reconstruction is one challenging procedure in pediatric liver transplantation (PLT).Here we review the first 115 microsurgical reconstructions of HA in PLT performed by a single surgeon,aiming to demonstrate the learning curve and the problems encountered.Methods From July 2016 to January 2017,a series of 115 microsurgical reconstructions of HA in PLT for end-stage liver disease were finished by one single surgeon with 4-year liver surgery experience and 2-week microsurgical training.HA reconstruction was performed with an operating microscope (Carl-Zeiss S88).Reconstruction was completed with interrupted sutures with 8-0 or 9-0 Prolene using the double clip for fixation.The blood flow was examined by Doppler scan daily after PLTs in first week and then once in 2nd week and first month for patency.A total of 143 artery anastomoses were performed in 115 PLTs.The age ranged from 3 months to 9 years.Indications for PLT included biliary atresia (105/115),Alagille syndrome (5/115),PFIC (3/115),Caroli disease (1/115),methylmalonicacidemia (1/115) and glycogen storage disease (1/115).Most of the PLTs were living donor liver transplantation (107/115),along with OLT (5/115) and split LT (3/115).Results The diameter of the arteries was mostly less than 2 mm (98/115).Up to date,one HA thrombosis (HAT) occurred at D8 after LT and 4 cases suspected as temporal HA stenosis (HAS) around 2 weeks after LT,which manifested as low velocity (<20 cm/s) and resistance index (<0.50) by Doppler.The HAT case failed in emergent re-anastomosis,but had a spontaneous recanalization at 3 weeks and is now in good condition without biliary problem.All the HAS children recovered to normal flows at first month.All children with HA complications started warfarin upon detection,with a targeted INR between 1.5-2.0.There were 6 deaths in this series including 5 cases of infections and 1 case of graft failure.Learning curve suggested a two phases growth (first 44 cases practicing phase vs.next 71 cases mature phase),which can be attributed to experience accumulation in terms of precise of manipulation,choice of inflow arteries for better match and stronger pulsation,avoidance of length redundant,prevention of kink.All the HAT and HASs happened in practicing phase while outcomes were excellent in mature phase.Moreover,time for each anastomosis was significantly shortened in second phase from 45-70 min to 30-55 min.Conclusion Microsurgical technique is highly safe in pediatric HA reconstruction,especially for very tiny arteries.It is possible to achieve low risk of complications for a new surgeon with adequate experience in liver surgery and microsurgical training.However,more surveillance and timing anticoagulation therapy is required before the mature of microsurgical technique.

After more than 20 years of development, pediatric liver transplantation has become a routine surgical practice in China, and currently ranks first in the world in terms of surgery quantity yearly. Further improving of liver transplantation technique and enhancing postoperative management to enable pediatric liver transplantation patients to return to normal social life are challenges for the academic community. The development of precision surgery, minimally invasive technology, big data information interconnection, and artificial intelli-gence has also brought new opportunities to researchers. The authors discuss the indications, surgical techniques, postoperative management system, immune suppression and tolerance, social humanities and ethics of pediatric liver transplantation in China, in order to promote the development of related fields of pediatric liver transplantation in China.

Objective To explore the diagnosis and treatment of parvovirus B19 infection-associated anemia after pediatric liver transplantation (LT) .Methods The clinical data were retrospectively reviewed for 2 children with severe anemia caused by parvovirus B19 infection after LT .Case 1 was a 2-year-old girl with a weight of 10 .7 kg .Classical orthotopic LT was performed due to ornithine carbamoyltransferase deficiency . Hemoglobin level began to progressively decline since Day 2 post-transplantation .And case 2 was a 5-month-old girl with an age of 5 months and a weight of 7 .2 kg .She underwent classic orthotopic LT for biliary atresia and decompensated liver cirrhosis .Hemoglobin level progressively declined at nearly 2 months post-transplantation . Results In case 1 ,bone marrow aspiration was performed at Day 54 post-transplantation .There was pure red cell aplasia and the detection of microvirus B19 nucleic acid was positive .Intravenous immunoglobulin was prescribed at a dose of 2 .5 g/day for 10 days ,tacrolimus was switched to cyclosporine and hemoglobin level spiked from 62 to 105 g/L after one-month treatment .In case 2 ,hemoglobin decreased to 44 g/L at 2 .5 months post-transplantation and the result of polymerase chain reaction of parvovirus B 19 was 9 .7 × 107 copies/ml .Then intravenous immunoglobulin was dosed at 2 .5 g/day for 10 days and hemoglobin level rose to 122 g/L at 25 days after treatment . Hemoglobin level decreased to 63 g/L again at 4 .5 months post-transplantation .Anemia was corrected by intravenous immunoglobulin injection plus a temporary discontinuation of tacrolimus and a reduced dose of tacrolimus .Conclusions Infection of parvovirus B19 can cause pure red cell aplasia after LT in children . Early diagnosis with intravenous immunoglobulin and modification of immunosuppressive regimen can obtain excellent therapeutic efficacies .

Objective To investigate the impact of adopting different dose grid resolution during volumetric modulated arc therapy (VMAT) planning on COMPASS pass rate.Methods A total of 10 patients with cervical cancer were enrolled.Four types of VMAT plans (plan1,plan2,plan3,plan4) were designed for each patient,with dose grid resolution of 0.2 cm × 0.2 cm × 0.2 cm,0.3 cm × 0.3 cm ×0.3 cm,0.4 cm ×0.4 cm ×0.4 cm and 0.5 cm ×0.5 cm ×0.5 cm,respectively.The plans were exported to Linac and conducted,then measured by COMPASS.The discrepancies were analyzed,which were obtained by comparing reconstructed dose from COMPASS and dose from TPS optimization.Results For tumor volume,the mean value of Dmean and D95 were ＜ 0.5％ and ＜ 1.3％ respectively,and the standard deviation were both ＜ 1.0％.For organs at risk (OAR),the max discrepancies were Dmean of femur with-6.7％,-7.0％,-8.0％,-5.8％,and V35 of rectum with 4.9％,-6.3％,-6.1％,-5.7％ in four types of VMAT plans.The γ (3％,3 am) rate of tumor volume was ＞95％ with standard deviation ＜ 2.5％,with no statistically significant difference among the four types of plans (P ＞0.05).The γ (3％,3 mm) rate of OARs were ＞ 98％ except femur (＞ 95％),and the standard deviations were within 1.9％-6.1％,with no statistical significance (P ＞0.05).The average γ rate of tumor volume and OARs were ＜ 0.4 except femur (＞ 0.4),with no statistically significant difference among four types of VMAT plans (P ＞ 0.05).Conclusions COMPASS pass rate was not influenced by the dose grid resolution between 0.2 ～ 0.5 cm for VMAT plan.

Objective To explore the experience of infantile liver transplantation ,reconstructing portal vein (PV) and avoid the higher incidence of portal vein low flow and complications .Methods The clinical data were reviewed for 152 infantile liver transplantations performed by a single surgery group .And 114 cases with PV risk factors underwent customized PV reconstructions .All of them were diagnosed as cholestatic liver diseases and 106 (93％ ) belonged to biliary atresia .Forty-two cases (36％ ) had 2 or more risk factors .Results Most cases (n= 106 ,93％ ) underwent living donor transplantations using lateral left graft while another 8 cases had deceased donor transplantations . Four types of PV reconstructions were adopted based upon individual conditions :left/right branch of PV trunk (n= 103) ,autogenous patch PV venoplastic reconstruction (n= 3) ,duct-to-duct of PV trunk (n= 5) and donor PV duct-to-recipient confluence of SMV/CV and SV (n= 3) .Graft size reduction was performed when GRWR > 4 .5％ (n= 16) .During a median follow-up period of 6 .5 (1 .5-13) months ,there were 3 LPVF (2 .6％ ) ,2PVS (1 .7％ ) and 1 PVT (0 .8％ ) .Three LPVF cases was corrected by PV stenting ,two cases of PVS were stable after anticoagulation therapy while one PVT case undergoing thromboectomy plus PV stenting resumed a normal PV flow .Conclusions PV reconstruction of high-risk infants require comprehensive risk evaluations ,precise surgical skills and customized strategies .For PV complications ,stenting is both safe and feasible .