Electronic portal imaging device(EPID) is now been used widely.EPID was initially used for the purpose of checking set-up error.There are two ways to verify set-up errors-on-line and off-line.With advanced knowledge about the dosimetry characteristics of EPID,the use of EPID for dosimetry verification was adapted from the research study to the clinic.EPID plays an important role in quality assurance of radiotherapy accessories including multileaf collimator(MLC)that has been most studied in the past couple of years.This article briefly reviews the clinical use of EPID.

Background and purpose:Radiotherapy (RT) is one of the most important therapeutic tools for esophageal cancer. Because tumors are heterogeneous, including for18F-FDG uptake and, most likely, for radioresistance, selective boosting of high FDG uptake zones within the tumor has been suggested. Therefore, it is critical to know whether the location of these high FDG uptake patterns within the tumor remains stable during RT.Methods:Twenty-two patients with esophageal squamous cell carcinoma treated with concurrent chemo-radiation underwent repeated18F-FDG PET-CT scans before RT and after 20 fractions of RT. On all scans, the high and low FDG uptake regions were auto-delineated using several standard uptake value (SUV) thresholds, varying from 40% to 70% of SUVmax on the pretreatment scan [gross tumor volume (GTV)40%pre, GTV50%pre, GTV60%pre, GTV70%pre] and from 70% to 90% of SUVmax on the dur-treatment scan (GTV70%dur, GTV80%dur, GTV90%dur) and ifxed thresholds of 2.5 and 5 (GTV2.5pre, GTV5pre). The volumes and overlap fractions (OF) of these delineations were calculated to demonstrate the stability of the high FDG uptake regions during RT.Results:The high uptake regions within the tumor during RT largely corresponded (OF>70%) with the 50% SUVmax high FDG uptake area (GTV50%pre) of the pretreatment scan. The hotspot within the residual area (GTV90%dur) was completely within the GTV and pre-radiotherapy high uptake regions (OF=100%). Although the location of the high FDG uptake patterns within the tumor during RT remained stable, the delineated volumes varied markedly.Conclusion:The location of the high FDG uptake areas within the tumor remained stable during RT. This knowledge may enable selective boosting of high FDG uptake areas within the tumor.

Objective To study the effects of mild hypothermia on cardiomyocyte contractility improvement after ischemia-repeffusion injury and on the preservation of well-functioning mitochondrial respiratory capability.Methods A total of 50 newborn SD rats 1 ～ 2 days after delivery were sacrificed and their hearts taken to preserved in 4 ℃ cold D-hanks buffer solution with 0.12％ pancreatic proteinase and collagenase and then processed with 37 ℃ water bath to collect the cardiomyocytes cultured in DMEM medium with 10％ FBS for 5 days.The cardiomyocytes of rats were subjected to ischemia/reperfusion,in vitro,by oxygen and glucose deprivation(OGD)/oxygen and glucose restoration(OGR).The cardiomyocytes of rats after ischemia/reperfusion were divided into three groups:control group,hypothemia group and normothermia group.Contractile frequency and velosity were determined before OGD and 0 h,0.5h,1 h,1.5 h and 2 h after OGR.Ultrastructure changes of cardiomyocytes and mitochondrion were observed under transmission electron microscope(TEM)0 h and 2 h after OGR as well as assessment ot respiratory rate and respiratory control rate(RCR)with Clark oxygen electrode in each group.All data were analyzed with statistical software of SPSS 13.0.Results Contractile function of cardiomyocytes in hypothermia group and normothermia group declined to nadir at 0 h after OGR(P =0.000)and the contractile function of cardiomyocytes in hypothermia group was improved one hour later,compared with the normothermia group(P =0.000).Obvious swelling of mitochondrion was observed under TEM in normothermia group with little alteration after OGR.The RCR assessments indicated respiratory function in normothermia group was impaired after OGR(P =0.000)and this may be responsible for contractility dysfunction.Conclusions Mild hypothemia used after ischaemia can optimize the contractility of cardiomyocytes after a normothermia OGR,and the well-functioning respiratory capability of mitochondrion may be preserved in this process.

SCLC can spare more volume of the normal lungs and e-sophagus, and has the ability of dose escalation.

Objective To investigate whether the change of beam set-up methods will influence the dosimetric quality of intensity modulated radiation therapy (IMRT) for non-small cell lung cancer (NSCLC).Methods Twenty-one stage Ⅰ-Ⅲ NSCLC patients were selected for this study.The technique of step and shoot was used and three different beam set-up methods were chosen for IMRT planning,including IMRT-7 with nine equal-spaced beams angled 0°,51°,102°,153°,204°,255°and 306°; IMRT-5 with five equal-spaced beams angled 0°,72°,144°,216°and 288°; and IMRT-5m which was created from IMRT-7 but excluded 2 fields (51°and 102° were omitted if there was lesion in the right lung,while 255°and 306° were excluded if there was lesion in the left lung).The dose constrains ofnormal lungs for IMRT were set according to V5-V60 of normal lungs obtained from the same patient's actually treated 3D-CRT dose volume histogram.The prescription dose for IMRT started from 65 Gy,and then escalated or decreased step by step by 2 Gy once a time until the best plan was obtained.Results For normal lung dose,IMRT-5m had lower V5-V25 than the other two groups; but there was no significant difference in V30-V40.IMRT-5 was the worst for V45-V60; and mean lung dose was lowest in IMRT-5m.Dose parameters of esophagus and spinal cord,target conformity index,and total monitor units were all similar among difference plans.IMRT-5m had lowest heart V40 compared to the other two groups.For target heterogeneity index,IMRT-5 was higher than IMRT-7,but there were no significant differences among IMRT-5m,IMRT-5 and IMRT-7.Compared to 3D-CRT,the prescription dose could be increased by (5.1 ±4.6) Gy for IMRT-7,(3.1 ±5.3) Gy for IMRT-5,and (5.5 ±4.8)Gy for IMRT-5m.Conclusion Fewer beams and modified beam angles could result in similar,even better plan quality.

Hyperthermia has been a research hot spot since it was approved by FDA as one of the 5 major therapeutic modalities for tumor since 1989. Pre-clinicaland clinical researches have confirmed the prominent radiosensitizing effect of hyperthermia. In this article, the research progress on hyperthermia combined with radiation therapy was summarized based upon clinical evidence. The challenges and issues during the procedure of hyperthermia combined with radiation therapy were analyzed from the perspectives of treatment temperature, frequency and interval time of hyperthermia, interval time and time sequence between hyperthermia and radiation therapy, etc. Besides, the application progress and prospect of hyperthermia combined with radiation therapy were reviewed, aiming to provide clinical evidence for the combination of hyperthermia and radiation therapy.

Objective To explore the differences in the hippocampal delineation among different radiologists and to evaluate the impact of the delineating guideline training upon improving the accuracy of target area.Methods In this prospective study,20 patients scheduled to receive whole brain radiation therapy were selected.Before and after the delineating guideline training,three physicians from Department of Radiation Oncology delineated the hippocampal targets three times for each patient.One physician from Department of Imaging Diagnosis delivered the delineating guideline training and delineated the hippocampus of 20 patients as the standard target area.The delineating targets before and after the training were statistically compared among different physicians.Results The conformity indexes with the standard target of three physicians before and after the training were 0.66±0.04 and 0.77±0.02,0.62±0.04 and 0.76± 0.02,0.49±0.05 and 0.74±0.04,respectively.The conformity indexes were all statistically increased after the training (all P＜ 0.05).The inter-observer variability significantly differed among different physicians before and after training (all P＜0.05).The coefficient of variance of hippocampal volume before and after training were 0.16±0.06 and 0.08±0.04 with statistical significance (all P＜0.05).Compared with all targets before training,the consistency of each physician was significantly improved after training (all P＜0.05).Conclusion Hippocampal delineation guideline training can improve the accuracy of delineation.

Chemoradiation has been the standard treatment of stage Ⅲ unresectable non-small cell lung cancer (NSCLC) for a long period of time. However, the clinical efficacy of chemoradiation has not been significantly improved in recent two decades. In the past 2-3 years, the role of immune-checkpoint inhibitors in metastatic NSCLC has been persistently strengthened. Moreover, the synergistic effect between radiotherapy and immune-checkpoint blockade has been conformed in pre-clinical and clinical studies. Recent clinical trials have demonstrated that the combination of radiotherapy and immune-checkpoint blockade has been proven to be more effective in the treatment of stage Ⅲ unresectable NSCLC. In this article, the latest clinical studies since 2017 regarding the application value of this combined treatment of stage Ⅲ unresectable NSCLC were summarized.

Lung cancer is the leading cause of cancer death worldwide as well as in China. For many years, conventional oncologic treatments such as surgery, chemotherapy, and radiotherapy (RT) have dominated the field of non-small cell lung cancer (NSCLC). The recent introduction of immunotherapy in clinical practice, led to a paradigm shift in lung cancer as in many other solid tumors. Recent pre-clinical and clinical data have shown RT may also modify antitumor immune responses through induction of immunogenic cell death and reprogramming of the tumor microenvironment. This has led many to reexamine RT as a partner therapy to immuno-oncology treatments and investigate their potential synergy in an exponentially growing number of clinical trials. Clinical trials combining radiotherapy and immunotherapy are attracting major attention, experts were invited to discuss frontier and controversial academic topics: (1) Recent developments of clinical synergy between radiation and immune checkpoint inhibitors (ICIs) in the treatment of NSCLC; (2) Will immunotherapy and radiotherapy increase the toxicity risk for cancer patients; (3) How to cope the mixed responses/disassociated responses phenomenon in checkpoint inhibition therapy to NSCLC with local ablative therapy; (4) Combining radiotherapy and immunotherapy in the treatment of NSCLC brain metastases.

Aiming at comparing the pre-operative and post-operative gait characteristics and therefore establishing post-operative rehabilitation guidance for patients with end-stage knee osteoarthritis (KOA) merged with varus deformity, this study captured the level walking and sit-to-stand trials of 9 patients with 3-dimensional motion analysis system and after which musculoskeletal multi-body dynamic analysis was conducted. The study indicated that the average range of motion (ROM) of the proposed-surgical knee was 24.4°-57.6° and that of the non-surgical knee was 22.5°-71.5°. The knee ROM of control group during level walking was 7.2°-62.4°. When the unilateral KOA patients stood up from chair to complete the sit-to-stand movement, the ground reaction forces (GRFs) symmetry was 0.72-0.85, which means that the non-surgical limb bear the majority of body weight. The GRFs of the bilateral KOA patients were smallest during the sit-to-stand movement. The strategy that the non-surgical limb dominates in loading bearing taken by the unilateral KOA patients to cover most post-operative daily activities could increase the risk of KOA among non-surgical side joints as a result of long-term excessive loading-bearing. The study, on kinematics and biomechanical characteristics of patients with KOA merged with varus deformity, could help to understand the pathogenesis of KOA merged with varus deformity from the perspective of biomechanics and to provide strong clinic guidance for the pre-operative evaluation, prevention and post-operative recovery for patients.