Nutritional problems prevail in 40%-80% of patients with malignant tumor,and malnutrition affects the treatments and outcomes of those receiving radiotherapy. Recently,nutritional support has emerged as an important therapy for the patients receiving radiotherapy. Appropriate nutritional interventions help improve the nutritional status,maintain the continuity of treatments,and improve the outcomes of the patients receiving radiotherapy. Oral nutrition supplements has been widely recommended by current guidelines as the first choice for nutritional support in clinical practice. It has been used for maintaining body weight before radiotherapy,enhancing nutrition intake during radiotherapy,and improving nutritional status and alleviating radiotherapy-related mucosa injuries after radiotherapy. However,as most patients receiving radiotherapy have not sufficiently understood the adverse effects of malnutrition,nutrition education is useful in helping the patients and their family members establish the basic concepts of nutritional support. This consensus paper provides recommendations and suggestions about the nutritional screening and evaluation,the peri-radiotherapy use of oral nutrition supplements,and nutrition education in the patients receiving radiotherapy,aiming to provide standardized procedures for guiding nutritional support in these patients.

Objective To investigate the tolerated dose of the optic nerves and chiasm in patients with locally advanced nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiotherapy (IMRT). Methods A retrospective analysis was performed on dose characteristics and the incidence of radiation optic neuropathy in 108 patients with locally advanced NPC treated with IMRT at D2>55 Gy in the optic nerves and chiasm in our hospital between May 2009 and December 2013. The Common Terminology Criteria for Adverse Events (CTCAE) Version 3.0 grading criteria were used for evaluating adverse reactions of the optic nerves and optic chiasm. A logistic regression analysis was performed to assess the risk factors for the development of radiation-induced optic neuropathy (RION). Resutls No patient had severe RION (grade 3-5),although 7 of the 108 patients had mild optic nerve disorder (grade 1-2). No patient-or treatment-related factors were found to be associated with the development of RION (P>0.05). With a median follow-up of 46 months (range,13-91 months),the 3-year estimated overall survival,local recurrence-free survival,and distant metastasis-free survival rates were 90.0%,94.5%,and 86.4%,respectively. Conclutions The dose constraint of<55 Gy derived for optic nerves and chiasm from conventional radiotherapy does not seem to apply to IMRT. For advanced NPC patients treated with IMRT,the dose constraints of optic nerves and chiasm might be relaxed in order to improve target coverage.

Objective To analyze the radiation doses to the head, body, and tail of the hippocampus in intensity-modulated radiotherapy (IMRT) for nasopharyngeal carcinoma (NPC). MethodsTen NPC patients treated with IMRT were selected, and the head, body, and tail of both hippocampi were delineated on T1-weighted images. The doses to the hippocampus were then analyzed. WAIS-CR speech test Resutls were tested by paired sample t-test. Resutls The mean doses to left and right hippocampi were 1147±976 cGy and 1011±602 cGy, respectively. The mean doses to the head, body, and tail of the left hippocampus were 1739±1317 cGy, 890±982 cGy, and 547±688 cGy, respectively (P=0.042);the mean doses to the head, body, and tail of the right hippocampus were 1691±942 cGy, 744±483 cGy, and 531±603 cGy, respectively (P=0.002).The dose to the hippocampus decreased from the head to the tail, and the irradiated volume also decreased as the dose varied. Conclutions The dose to hippocampus decreases from the head to the tail in NPC patients treated with IMRT, which is worthy of attention.

Objective To analyze setup errors in cone beam computed tomography (CBCT)-guided radiotherapy for nasopharyngeal cancer (NPC) and evaluate the use frequency of CBCT. Methods Twenty-six patients newly diagnosed with NPC who received CBCT scan no less than 3 times per week during the whole course (7 weeks) of intensity-modulated radiotherapy (IMRT) were enrolled as subjects. Two setup errors were recorded each week:the setup error in the first CBCT analysis (Ef) and the setup error in the subsequent CBCT analysis (Ec). Comparisons of Ef between two different weeks, Ec between two different weeks, and between Ef and Ec in the same week were made by analysis of variance. Resutls During the 7 weeks, there were no significant differences in Ef in the medial-lateral (ML), superior-inferior (SI), or anterior-posterior (AP) direction between any two weeks (all P>0.05);there were also no significant differences in Ec in the ML or SI direction between any two weeks (all P>0.05);there was a significant difference in Ec in the AP direction between two different weeks (P<0.05);there were no significant differences between Ef and Ec in the ML or SI direction in any week (P>0.05);there were also no significant differences between Ef and Ec in the AP direction in any week (P>0.05) except for the first week (P<0.05). Conclutions In IMRT for NPC, the setup errors in the ML and SI directions are stable in the whole course of radiotherapy, while the setup errors in the AP direction are different between the first week and subsequent weeks. Daily CBCT scan in the first week and weekly CBCT scan in the subsequent weeks are highly recommended for most patients to reduce the use frequency of CBCT.

Objective To analyze the survival of patients with esophageal squamous cell carcinoma (ESCC) treated by different regimens and different radiation doses and to explore the optimal radiation dose and subgroups with potential clinical benefit. Methods A total of 1387 patients with ESCC who received conformal radiotherapy or intensity-modulated radiotherapy in our hospital from July 2003 to March 2014 were enrolled in this retrospective study. The patients who received different radiation doses in radiotherapy alone or in concurrent chemoradiotherapy were analyzed. The log-rank test and Cox regression analysis were used to explore the optimal radiation dose and the benefited subgroups. Resutls A total of 780 patients only received radiotherapy. Among them,the median survival of patients receiving radiation dose<60 Gy (n=91),60 Gy (n=429),and>60 Gy (n=260) was 9,20,and 23 months,respectively,suggesting a significant difference (P=0.000).The patients with a radiation dose of 60 Gy had a similar survival curve to the patients with radiation dose>60 Gy,both significantly higher than that in patients with radiation dose<60 Gy (P=0.000,0.000).Totally 302 patients received concurrent chemoradiotherapy. Among them,the median survival of patients receiving radiation dose<60 Gy (n=18),60 Gy (n=224),and>60 Gy (n=60) was 22,34,and 15 months,respectively,suggesting a significant difference (P=0.004).The survival curve showed no significant difference between the patients with radiation dose<60 Gy and>60 Gy (P=0.952),while the patients with a radiation dose of 60 Gy had a better survival compared with the patients with radiation dose<60 Gy or>60 Gy. The Cox multivariate regression analysis indicated that the ESCC patients receiving radiotherapy alone or concurrent chemoradiotherapy had different prognosis;gross tumor volume (GTV) and radiation dose were two independent prognostic factors in the same treatment model (P=0.045,0.001).In radiotherapy alone,radiation dose ≥60 Gy was a protective factor for the patients’ survival (P=0.000).In concurrent chemoradiotherapy,a radiation dose of 60 Gy was a protective factor,while radiation dose<60 Gy or>60 Gy presented no survival benefit (P=0.051). Conclutions The optimal radiation dose is no less than 60 Gy in ESCC patients treated by radiotherapy alone. If the patients receive concurrent chemoradiotherapy,the radiation dose of 60 Gy is recommended.

Objective To analyze the feasibility of intensity-modulated radiation therapy (IMRT) with concurrent chemotherapy in patients with locally advanced Siewert type Ⅱ and Ⅲ adenocarcinoma of the esophagogastric junction (AEG). Methods A prospective study was performed on 45 patients with locally advanced Siewert type Ⅱ and Ⅲ AEG. These patients received two cycles of XELOX chemotherapy and concurrent IMRT to the involved field (45 Gy/25 f, 5 f/week) for 6 to 8 weeks before surgical resection. The patients ingested 800 to 1000 ml water to distend the stomach before computed tomography (CT) scan. The gross tumor volume of the primary tumor (GTV-t) was delineated on the CT image with a stomach wall thickness of>5 mm. GTV-t was expanded by a 2.0 cm margin along the esophagus, a 1.5-2.0 cm margin along the stomach, and a 0.8 cm margin axially outward to generate the clinical target volume of the primary tumor (CTV-t). GTV-lymph node (GTV-nd) was delineated based on CT/magnetic resonance imaging scan. CTV-nd only included GTV-nd and the involved lymph nodes. Planning target volume was generated by expanding the CTV by 0.8 to 1.0 cm. The feasibility of target volume delineation was explored by analyzing postoperative pathological examination Resutls and radiotherapy toxicities. Resutls All the 45 patients completed preoperative concurrent chemoradiotherapy and surgery, with two cycles of chemotherapy in 39 patients and one cycle in 6 patients. The rates of R0 resection and pathological complete response (pCR) were 95.6%(43/45) and 22.2%(10/45), respectively. There were 10(22.2%), 17(37.8%), 15(33.3%), and 3(6.7%) patients with tumor regression grades 0, 1, 2, 3, respectively. The rate of lymph node metastasis was 37.8%(17/45), and the lymph node ratio was 4.33%(46/1062). The postoperative pathological examination showed that T and N downstaging after surgery was observed in 24 and 26 patients, respectively;the proportions of patients with T3-T4 tumors and positive lymph nodes after surgery declined by 51.1%(P=0.000) and 42.2%(P=0.000), respectively. The overall incidence of radiation esophagitis/gastritis was 44.4%(20/45), and the incidence rates of grade 1, 2, and 3 radiation esophagitis/gastritis were 18%, 22%, and 4%, respectively. The incidence of acute radiation pneumonitis was 6.7%(3/45), all in grades 1 and 2. There was one perioperative treatment-related death. Conclutions Two cycles of XELOX chemotherapy combined with concurrent 45 Gy radiotherapy before surgery in patients with locally advanced Siewert type Ⅱ and Ⅲ AEG can achieve a relatively high pCR rate, effectively reduce the lymph node metastasis rate, achieve downstaging, and increase R0 resection rate. This regimen has many good advantages, including low incidence of acute toxicities, good tolerability, and acceptable rate of perioperative treatment-related deaths. The target volume delineation involving metastatic lymph nodes is feasible.

Objective To investigate the significance of computed tomography (CT) and 3.0 T magnetic resonance imaging (MRI) in intensity-modulated radiotherapy (IMRT) for esophageal carcinoma. Methods Thirty-five patients newly diagnosed with esophageal carcinoma who received radical radiotherapy in our hospital from November 2013 to April 2015 were enrolled as subjects. Target volume was delineated on the CT images and MRI images (T2-weighted and diffusion-weighted fusion images). The MRI-and CT-based IMRT plans were designed using the same dose prescription and dose constraints for organs at risk (OAR). The target volume,prescribed dose,and doses for OAR were compared between the two plans. Resutls In the two plans,dose distribution and planning parameters met the clinical requirement. The length of lesion,gross tumor volume (GTV),and planning target volume (PTV) defined by 3.0 T MRI were significantly smaller than those defined by CT (P=0.00,0.03,0.03). There were no significant differences in the D2%,D98%,D50%,homogeneity index,or conformity index for primary GTV (PGTV) and PTV-PGTV between the two plans (all P>0.05). Compared with the CT-based plan,the 3.0 T MRI-based plan had a significantly smaller mean dose to the lungs and an insignificantly smaller actual dose to the lungs (P=0.00;P>0.05). There were no significant differences in maximum doses tolerated by the spinal cord or heart between the two plans. Conclutions In terms of target volume delineation and dosimetric parameters,both CT-and 3.0 T MRI-based plans meet the clinical requirement. The 3.0 T MRI-based plan may provide potential benefits for some OAR due to a smaller target volume compared with the CT-based plan.

Objective To compare the geometric differences of gross tumor volumes (GTV) and displacements of selected clips propagated by rigid image registration (RIR) and deformable image registration (DIR) at end-inhale phase (CT0) and end-exhale phase (CT50) based on four-dimensional computed tomography (4DCT) of the whole breast after breast-conserving surgery (BCS). Methods Forty-four patients who underwent 4DCT simulation scans after BCS were selected. The GTV and displacements of selected metal clips at CT0 and CT50 were manually delineated by the same radiotherapy physician. Subsequently,the GTV and displacements of selected clips from CT0 images were transformed and propagated to CT50 images using RIR and DIR.The geometric differences of GTV and displacements of surgical clips from DIR were compared with those from RIR based on the dice similarity coefficient (DSC) and the displacements of the center of mass (COM) in the three-dimensional (3D) directions. Resutls The mean DSC was 0.86±0.04 for RIR and 0.87±0.04 for DIR (P=0.000).The displacements of COM in 3D directions from RIR were significantly greater than those from DIR (1.22 mm vs. 1.10 mm,P=0.000).In the anterior-posterior direction,the displacements from RIR were significantly greater than those from DIR for both GTV and selected clips (P=0.000).However,in the left-right and superior-inferior directions,there were no significant differences in displacements between RIR and DIR for both GTV and the selected clips (all P>0.05). Conclutions DIR can improve the overlap for GTV registration from 4DCT scans at CT0 and CT50.Furthermore,DIR is superior to RIR in reflecting GTV and the displacements of selected clips in anterior-posterior direction induced by respiratory movement.

Objective To investigate the clinical value of vacuum pad and body film fixation in radiotherapy for thoracic and abdominal tumors. Methods A total of 240 patients with thoracic and abdominal tumors who were treated with radiotherapy were randomly selected and divided into group A (simple vacuum pad fixation, 60 patients), group B (simple body film fixation with unimproved solid plate, 60 patients), and group C (vacuum pad and body film fixation with improved solid plate, 120 patients).The difference between groups were analyzed with single variance analysis method. Resutls The setup error was small in group C and large in groups A and B. There were significant differences in the setup error between the three fixation Methods (P=0.000). Conclutions A combination of vacuum pad and body film fixation is better than vacuum pad or body film fixation in radiotherapy for thoracic and abdominal tumors. The combination method has many benefits, including simple and convenient operation, comfortable and repeatable body fixation, reduced artificial errors, and improved positioning precision.

Objective To investigate the dosimetric difference between inverse planning simulated annealing (IPSA) and manual optimized plan for isodose line in interstitial brachytherapy for locally advanced cervical cancer and to provide a better optimization method for clinical application. Methods A total of 104 patients with cervical cancer were enrolled in this study. They received pelvic external beam radiotherapy and interstitial brachytherapy in five fractions. Both IPSA and manual optimized plan for isodose line were used to optimize the dose in each fraction. Dose volume parameters of the two plans were compared to analyze the dosimetric outcome by paired t-test. Resutls There were nosignificant differences in mean D90 and D100 for high-risk clinical target volume (HR-CTV) and D90 for intermediate-risk clinical target volume (IR-CTV) between the two groups (P>0.05). The IPSA group had a significantly higher D100 for IR-CTV than the manual optimized group (58.36±2.06 Gy vs. 53.99±2.17 Gy, P=0.025). For organs at risk, the IPSA group had asignificantly lower mean rectum D2cc and a significantly higher bladder D2cc than the manual optimized group (68.53±2.85 Gy vs. 71.77±1.79 Gy, P=0.002;80.49±3.36 Gy vs. 78.71±2.64 Gy, P=0.034). There was no significant difference in sigmoid D2cc between the two groups (P>0.05). The IPSA group had significantly higher relative dose homogeneity index (HI) and conformity index (CI) of radiation dose for target volume than the manual optimized group (P<0.05), and there was nosignificant difference in overdose volume index (OI) between the two groups (P=0.107). ConclusionsCompared with manual optimized plan for isodose line, IPSA can improve the dose distribution of tumor tissue, reduce mean rectum D2cc, and increase CI and HI, so it is a preferable optimized treatment planning method in clinical application.

Objective To discuss and evaluate the dosimetric characteristics of different plans implementing stereotactic radiotherapy (SRT) for intracranial tumors using Fixed and Iris collimators of CyberKnife VSI. Methods Twenty patients with intracranial tumors were selected and divided into group A with a small target volume (≤30 cm³) and group B with a large target volume (≥30 cm³). There were 10 patients in each group, and the prescribed dose to the target was 21 Gy in 3 fractions. For each patient, two treatment plans were designed using Fixed and Iris collimators. By analyzing the dosimetric parameters such as conformity index (CI), homogeneity index (HI), gradient index (GI), gradient score index (GSI), and organs at risk (OAR), the quality and efficiency of the plans were evaluated in order to discuss the beam characteristics for two sets of collimators. The difference was analyzed with the paired t-test. Resutls The mean time of Iris plan for delivering was significantly less than that of Fixed plan (group A:P=0.001;group B:P=0.000). In group B, the peripheral dose (20% and 10% of the prescribed dose) volumes of Fixed plan were significantly less than those of Iris plan (P=0.001 and 0.009). For OAR, Dmin of the visual pathway and Dmean or Dmin of the eyeball in group B were significantly different between Fixed and Iris plans (all P<0.05), while in group A, only Dmin of the optic chiasm was significantly different between the two plans (P=0.043). For the other parameters of targets, there were no significant differences between Fixed and Iris plans in both groups (all P>0.05). Conclutions Apart from less treatment time in the Iris plan, there are no significant dosimetric differences between the two collimator plans of CyberKnife VSI in treating small intracranial tumor. For the large and complex tumor, although Iris plan meets the requirement for OAR dose constraints, its low-dose volumes are larger than those of Fixed plan. Further studies of the dosimetric characteristics in CyberKnife should be done.

Objective To investigate the benefits of replanning after induction chemotherapy (IC) by analyzing the dosimetric impact of IC on intensity-modulated radiotherapy (IMRT) for locally advanced nasopharyngeal carcinoma (NPC) and the dosimetric characteristics of replanning after IC, and to provide data for the rational design of clinical radiotherapy plans. Methods 16 NPC patients underwent contrast-enhanced CT scan once before and after IC. Target volumes were delineated and the chemotherapy plans were created, defined as Plan-1 and Plan-2, respectively. Then the target structure after IC was copied to Plan-1, generating the third plan, defined as Plan-1-2. The paired t-test was used to compare the dosimetric parameters between Plan-1 and Plan-1-2 and between Plan-2 and Plan-1-2. Resutls Plan-1 vs. Plan-1-2:Plan-1-2 showed significantly reduced Dmean of target volume compared with Plan-1(P<0.05). Plan-1-2 significantly increased Dmean and Dmax of the spinal cord (P<0.05), although significantly reduced Dmean of the brain stem and Dmax of the temporal lobes compared with Plan-1. Plan-1-2 also had significantly reduced conformity index (CI) and significantly increased homogeneity index (HI) for the target volume compared with Plan-1(P<0.05). Plan-2 vs. Plan-1-2:Compared with Plan-1-2, Plan-2 significantly increased Dmean and Dmin of gross tumor volume (GTV) and primary GTV (P<0.05) and significantly reduced Dmean of the temporal lobes and Dmax and Dmean of the spinal cord (P<0.05), with Dmax decreased to 430.48 cGy;Plan-2 had significantly increased CI and significantly reduced HI for the target volume compared with Plan-1-2(all P<0.05). Conclutions IMRT plan-1 after IC has worse dosimetric distribution, while replanning after IC has more dosimetric benefits.

Objective To investigate the effects of bone marrow (BM)-sparing pelvic intensity-modulated radiotherapy (IMRT) after surgery for cervical cancer on radiation dose to the target volume,organs at risk (OAR),and hematologic toxicity. Methods Ten patients with cervical cancer who would receive postoperative radiotherapy were selected. BM-sparing pelvic IMRT and conventional IMRT were performed for the same image by the Varian planning system. The radiation dose to the pelvis,the dose distribution of the target volume,and the radiation dose to OAR were compared between the two plans. A total of 30 patients with cervical cancer who had received postoperative radiotherapy were selected to investigate the relationships of the radiation dose to the pelvis with the lengths of the pelvis in coronal axis,sagittal axis,and vertical axis and the pelvic volume. A total of 41 patients with cervical cancer who would receive postoperative radiotherapy were randomly divided into observation group and control group. The observation group was given BM-sparing IMRT,while the control group was given conventional IMRT.The incidence of grade ≥2 hematologic toxicity was compared between the two groups and the relationship between the hematologic toxicity and the radiation dose to the pelvis was investigated. Resutls Both groups showed excellent dose coverage to the clinical target volume. There was no significant difference in radiation dose to the OAR between the two groups (all P>0.05).However,the observation group had significantly lower Dmean,V10,V20,V40,and V50 of the pelvis than the control group (P=0.003-0.045).The Pearson correlation analysis showed that Dmean,V20,V30,V40,and V50 of the pelvis were negatively correlated with the length of the pelvis in coronal axis (P=0.008-0.038).The observation group had a significantly lower incidence of hematologic toxicity than the control group (P=0.019).The logistic regression analysis showed that the development of hematologic toxicity was significantly associated with V20 of the pelvis (OR=1.191,P=0.042). Conclutions BM-sparing IMRT after surgery for cervical cancer can reduce the radiation dose to the pelvis and the incidence of blood toxicity. The radiation dose to the pelvis is negatively correlated with the length of the pelvis in coronal axis. The development of hematologic toxicity is associated with V20 of the pelvis.

Objective To determine whether Auto-Planning-based volumetric modulated radiotherapy (Auto-VMAT) planning can improve planning efficiency without compromising plan quality compared with current manual trial-and-error-based volumetric modulated arc therapy (Manual-VMAT) planning for patients with rectal cancer. Methods Ten patients with stage Ⅱ-Ⅲ rectal cancer who underwent Dixon surgery were enrolled as subjects. The Pinnacle 9.10 planning system was used to design Manual-VMAT and Auto-VMAT plans. Dose distribution, homogeneity index (HI), conformity index (CI), Dmean values of different organs at risk or dose-volume histogram of regions of interest, total planning time, and manual planning time were compared between the two plans. The differences were analyzed by paired t test. Resutls Dosimetric prescriptions were achieved in both plans. There were no significant differences in HI or CI between the Auto-VMAT plans and the Manual-VMAT plans (0.058 vs. 0.058, P=0.972;0.921 vs. 0.940, P=0.115). Compared with the Manual-VMAT plans, the V40, Dmean, and D50% of the bladder were significantly reduced by 25.6%, 11.5%, and 8.9%, respectively, in the Auto-VMAT plans (P=0.004, 0.016, 0.001);the V40, Dmean, and D50% of the small intestine were also significantly reduced by 12.1%, 5.4%, and 6.8%, respectively, in the Auto-VMAT plans (P=0.023, 0.001, 0.001);the V30, Dmean, and D50% of the left and right femoral heads were slightly reduced in the Auto-VMAT plans. The Auto-VMAT plans had significantly longer total planning time but significantly shorter manual planning time than the Manual-VMAT plans (50.38 vs. 36.81 min, P=0.000;4.47 vs. 16.94 min, P=0.000). Conclutions Compared with the Manual-VMAT plans, the Auto-VMAT plans have substantially shorter manual planning time and improved planning efficiency.

Objective To investigate the dosimetric feasibility of volumetric modulated arc therapy (VMAT) with a simultaneous integrated boost (SIB-VMAT58.75 Gy) for preoperative chemoradiotherapy inpatients with locally advanced rectal cancer (LARC),and to provide a basis for clinical practice. MethodsNine patients with stage Ⅱ-Ⅲ rectal cancer who underwent preoperative concurrent chemoradiotherapy were involved in the study,and two plans were performed for each patient:SIB-VMAT58.75 Gy and VMAT50.00 Gy. For the SIB-VMAT58.75 Gy plan,the prescribed dose was 58.75 Gy (2.35 Gy/fraction) for the local rectal tumor and positive lymph nodes (GTV 58.75 Gy),and 50 Gy (2 Gy/fraction) for the regions at high risk of harboring microscopic disease (pelvic lymphatic drainage area)(PTV50 Gy).For the VMAT50.00 Gy plan,the prescribed dose was 50 Gy (2 Gy/fraction) for the regions at high risk of harboring microscopic disease (pelvic lymphatic drainage area) without a boost. The conformity index (CI),homogeneity index (HI),and dose for target areas and organs at risk (OAR) were assessed according to the dose-volume histogram. The paired t-test or nonparametric rank test was used to compare the differences between the two plans. Resutls Both plans met the prescription goal for PTV dose coverage. There was no significant difference in CI for the PTV between the two plans (1.0±0.0 vs. 1.0±0.0,P>0.05).The SIB-VMAT58.75 Gy plan had a worse HI than the VMAT50.00 Gy plan (0.2±0.2 vs. 0.1±0.0,P<0.05).There was no significant difference in V10-V50 of the small intestine,bladder,femoral heads,and pelvis between the two plans (P>0.05),but D2 cm³ of the small intestine was significantly higher in the SIB-VMAT58.75 Gy plan than in the VMAT50.00 Gy plan (P=0.038). Conclutions The SIB-VMAT58.75 Gy plan for LARC achieves required target volume dose coverage and OAR dose constraints,which is safe and feasible in terms of dosimetry,and its clinical efficacy and adverse effects need further evaluation.

Objective To investigate the optimal distance between the upper and lower targets in the subsection total body irradiation (TBI) using helical tomotherapy, and to analyze the dose distribution of abutment regions. Methods A total of 8 patients with acute leukemia with a height of about 120 cm were involved in the study. All patients were scanned from the calvarium to the toe by computerized tomography (CT, Siemens) with a thickness of 5 mm, and a lead wire was placed at a point 10 cm above the patella as a marker of the boundary between the upper and lower targets. The delineation of target volumes and organs at risk (OAR) was performed in the Varian Eclipse 10.0 doctor workstation. The different distances between the lead wires and the boundary of the two targets were delineated, and images were transferred to the HT workstation to design the radiotherapy planning, including Jaw width (5 cm), modulation factor (1.8), and pitch (0.43). The plans were superimposed together, and then the dose distribution in abutment regions with different target gaps was analyzed to find the optimal distance. Resutls When the target gap was 5 cm, the dose distribution in abutment regions was satisfactory. However, the dose was obviously insufficient when the gap was more than 5 cm;the doses in abutment regions significantly exceeded the prescribed doses when the gap was less than 5 cm. Conclutions In the subsection TBI using HT, different parameters were designed, including Jaw width (5 cm), modulation factor (1.8), pitch (0.43), and slice thickness (5 mm). The upper and lower borders of the targets should be 2.5 cm away from the lead wire, that is, a gap of 5 cm, thus avoiding the dose-related hot or cold spots in the target convergence and ensuring a safer and more accurate radiotherapy.

Objective To compare five different detectors in output factor (OF) measurement for the CyberKnife (CK) system,and to select a suitable detector. Methods OFs for 12 different sizes of CK collimators were measured by EBT3 films and 5 different commercially available detectors,consisting of diode detectors PTW 60017 and PTW 60018,ionizing chamber detectors PTW 31010 and PTW 30013,and diamond detector PTW 600019.OF was compared between different detectors and different measurement orientations. Resutls When the size of collimator was larger than 30 mm,the OF deviation among five detectors was less than 1%.When the size of collimator was smaller than 30 mm,however,the OF deviation among five detectors became large and obviously increased with the decrease in the size of collimator. With a OF deviation less than 2%,PTW 60019 achieved the best agreement with films. Compared with films,diode detectors gave slightly higher OFs,while ionizing chamber detectors gave much smaller OFs. The OF measurement was also affected by measurement orientation. PTW 60019 gave a smaller OF in the direction parallel to the central axis than in the direction perpendicular to the central axis of the radiation field,while PTW 31010 had an opposite result. Conclutions When the size of collimator is larger than 30 mm,PTW 31010,PTW 60017,PTW 60018,and PTW 60019 can be directly used for the OF measurement. When the size of collimator is smaller than 30 mm,correction is needed for the OF measurement using the above detectors. PTW 30013 is not suitable for the OF measurement in the small radiation field.

Objective To investigate the effect of E1A gene on the radiosensitivity of human nasopharyngeal carcinoma cells and its possible mechanism. Methods The E1A gene was transfected into nasopharyngeal carcinoma CNE-2R cells by adenovirus vector. The expression of E1A gene was detected by RT-PCR. Untransfected CNE-2R cells (PBS group) and CNE-2R cells transfected with empty vector Ad-β-gal (Ad-β-gal group) and E1A (Ad-E1A group) were given 0 Gy, 2 Gy, 4 Gy, 6 Gy, 8 Gy 6 MV X-ray irradiation. The changes in radiosensitivity of CNE-2R cells were determined by colony-forming assay. Flow cytometry was used to analyze cell apoptosis in each group. The expression of NF-κB, CK2α, Bcl-2, and cleaved caspase-3 was measured by Western blot. Resutls RT-PCR confirmed that the E1A gene was transfected into CNE-2R cells and stably expressed. The Ad-E1A group had a significantly lower plating efficiency than the PBS group and the Ad-β-gal group (P<0.05). The Ad-E1A group had significantly lower cell survival rate at 2 Gy irradiation than the PBS group and the Ad-β-gal group (0.217 vs. 0.602, P<0.05;0.217 vs. 0.585, P<0.05). The Ad-E1A group had a significantly higher α/β value than the PBS group and the Ad-β-gal group (24.680 vs. 5.268, P<0.05;24.680 vs. 5.132, P<0.05). Flow cytometry Resutls showed that irradiation alone could promote the apoptosis of CNE-2R cells, when combined with E1A gene, the apoptosis rate was significantly increased (P<0.05). Western blot Resutls showed that E1A gene down-regulated the expression of NF-κB/p65, CK2α, and Bcl-2 and up-regulated the expression of cleaved caspase-3. Conclutions E1A gene can enhance the radiosensitivity of nasopharyngeal carcinoma cells by inhibiting the expression of CK2 to block the NF-κB signaling pathway and promoting cell apoptosis.

Objective The purpose of this study is to investigate the effect of miR-449a on pancreatic cancer cells and the molecular mechanism. Methods The expression levels of miR-449a in pancreatic cancer cells treated or untreated with radiation was detected by qRT-PCR.High expression of miR-449a was achieved by transfecting miR-449a mimics into SW1990 cells. The cell growth,apoptosis and colony formation ability was assessed by MTT assay,flow cytometry and colony formation assay,respectively. The relationship of miR-449a and Cyclin D1 was determined by the TargetScan and dual luciferase reporter. Immunohistochemistry was used to examine protein levels of Cyclin D1 in pancreatic cancer and normal pancreas tissues. Si-Cyclin D1 was used to detecte the effect of Cyclin D1 on radiosensitivity of pancreatic cancer cells. Resutls The expression levels of miR-449a in pancreatic cancer cells with radiation treatment were decreased significantly. Mir-449a mimics increased the cell proliferation rates and apoptosis rates obviously,and decreased the colony formation ability in SW1990 cells treated with radiation. Resutls from the TargetScan and dual luciferase reporter showed that Cyclin D1 was the target of miR-449a. The positive staining rates of Cyclin D1 in pancreatic cancer tissue (85.7%,30/35) was higher than those in normal pancreas tissue (20%,2/10).Knockdown of Cyclin D1 enhanced the radiosensitivity of pancreatic cancer cells. Conclusion MiR-449a enhances the radiosensitivity of pancreatic cancer cells by targeting Cyclin D1.

At present, although magnetic resonance imaging (MRI) is not a routine examination of esophageal cancer, the preliminary Resutls of some studies have indicated that MRI may become an important alternative for esophageal cancer staging, radiotherapy target delineation, and efficacy assessment. This article mainly discusses the value of MRI in the staging and radiotherapy for esophageal cancer.

The rate of locoregional recurrence (LR) is high in patients with esophageal squamous cell carcinoma after surgery, and salvage treatment for LR is mainly performed with radiotherapy or radiochemotherapy. However, the target and dose of radiotherapy and chemotherapy regimen are inconsistent. Several factors may affect the effect of salvage treatment and even lead to recurrence, such as age, performance status score, recurrence site, target area, and the number and size of lesions, as well as the technology and dose of radiotherapy, chemotherapy regimen, and the pattern of radiotherapy and/or chemotherapy. The article reviews the above aspects to guide clinical treatment for these patients.

Prostate cancer tends to progress to castration-resistant prostate cancer within 24 months after castration. For the management of castration-resistant prostate cancer, the biggest challenge is therapeutic resistance which includes radiotherapy resistance. Relevant studies suggest that the radiotherapy resistance of castration-resistant prostate cancer is associated with prostate cancer stem cells and miRNA related to prostate cancer stem cells. This article reviews the research advances in the radiotherapy resistance of castration-resistant prostate cancer in terms of the possible mechanisms of castration-resistant prostate cancer, prostate cancer stem cells, and miRNA related to prostate cancer stem cells.

Poly (ADP-ribose) polymerase-1(PARP-1), a ubiquitous and abundant nuclear protein composed of amino-acid residues, plays an important role in the process of DNA damage repair. In recent years, some studies have confirmed that PARP-1 is closely related to the development and progression of tumors, and may influence the tumor radiosensitivity. This article summarizes the relationship of PARP-1 and its inhibitors and the development, progression, and radiosensitivity of tumors.

With the rapid development of radiotherapy technology, traditional quality management will shift from a device-centric strategy to a process involving multiple people. In recent years, failure mode and effect analysis (FMEA) based on predictive risk assessment has gradually been applied in the quality management of radiotherapy process. The FMEA approach mainly includes four steps:process tree management, FMEA, error tree analysis, and the design of scheme for process quality management. The specific Methods and Resutls are different due to the specificity of radiotherapy process and the subjectivity of participants. Its reliability and feasibility have also been considered and verified. This article reviews the application of FMEA approach in some radiotherapy centers.