Respiratory motion management was crucial importance in radiotherapy. Our study aimed to explore the dosimetric and radiobiological benefits of various respiratory motion management strategies in liver tumor patients undergoing stereotactic body radiotherapy (SBRT). Respiratory motion images of 23 liver tumor patients were obtained by 4DCT scan under abdominal compression (AC) and free-breathing (FB). Group A included all 23 patients, while group B focused on 11 patients with tumors < 5 cm in diameter. Dosimetric and radiobiological parameters were recorded and compared across three treatment plans for each patient: PlanFB, PlanAC, and PlanGAT(Respiratory gating). For dosimetric parameters, compared to PlanAC, PlanGAT further significantly reduced liver Dmean, Vd<21.5 Gy, V10Gy; right kidney Dmean; duodenum Dmean, D0.5cc, 1cc, 5cc, 10cc; intestine Dmean, D0.5cc, 5cc, 10cc; stomach Dmean and spinal cord Dmean, V5Gy in group A; however, in Group B, PlanGAT only showed significantly reductions in liver Dmean and duodenum Dmean, D5cc, 10cc. In terms of radiobiology, compared with PlanFB, PlanAC significantly reduced liver NTCP (p = 0.033) in Group B, whereas no difference was observed in Group A (p = 0.231). Additionally, compared to PlanAC, PlanGAT further reduced liver NTCP (p = 0.001), liver EUD (p < 0.001) and right kidney EUD (p < 0.001) in Group A; however, in Group B, PlanGAT did not significantly decrease liver NTCP (p = 0.136), indicating that AC offers comparable benefits to GAT. The Pearson’s correlations between the reductions in dosimetric and radiobiological parameters and tumor motion or target volume were stronger in Group B than in Group A under AC. So, GAT provides the greatest dosimetric and radiobiological benefits for liver tumors treated with SBRT, while AC offers comparable benefits for liver tumors with < 5 cm in diameter. Thus, given its technical simplicity, AC is recommended for liver tumors < 5 cm in diameter undergoing SBRT.

目的 对使用AccuContour软件自动勾画全脑全脊髓放射治疗(CSI)患者靶区和危及器官(OARs)进行风险评估和风险应对.方法 选取 2012 年 1 月至 2022 年 12 月于医院接受全脑全脊髓放射治疗(CSI)的40例患者为研究对象,其中仰卧位和俯卧位各20例,且同一体位组内成人和儿童各10例.手动和自动勾画4组患者靶区和OARs.界定风险准则,勾画结果以德尔菲法进行后果分析,对靶区和OARs做出风险分型,并逐例逐层回顾统计,通过危险与可操作性分析法进行可能性分析,对勾画差异做出归因分类.结果 脑、肝脏、左右肺、左右肾、心脏和左右眼球为鲁棒型;甲状腺、左右腮腺为平衡型;喉、气管、食管、胃、脊髓腔、左右视神经和左右晶体为审慎型.自动勾画和手动勾画的差异归因可分为Ⅰ～Ⅶ类.根据器官分型和归因分类,对开发方和应用方提出不同的风险应对建议.结论 AccuContour软件应用于CSI患者的靶区和OARs自动勾画具有较高的临床价值,但需完善前期风险评估和策略应对,确保智能勾画的安全、可靠、可控及可持续发展.

Objective The present study aimed to investigate the dose differences and radiobiological assessment between Anisotropic Analytical Algorithm (AAA) and Acuros External Beam (AXB) with its 2 calculation models, namely, dose-to-water (AXB-Dw) and dose-to-medium (AXB-Dm), on esophageal carcinoma radiotherapy treatment plans. Materials and methods The AXB-Dw and AXB-Dm plans were generated by recalculating the initial 66 AAA plans using the AXB algorithm with the same monitor units and beam parameters as those in the original plan. The dosimetric and radiobiological assessment parameters were calculated for the planning target volume (PTV) and organs at risk (OARs). The gamma agreement for the PTV and the correlation between it and the volume of the air cavity and bone among the different algorithms were compared simultaneously. The dose discrepancy between the theoretical calculation and treatment planning system (TPS) when switching from AXB-Dm to AXB-Dw was analyzed according to the composition of the structures. Results The PTV dose of AXB-Dm plans was significantly smaller than that of the AAA and AXB-Dw plans (P < .05), except for D 2 . The difference values for AAA vs AXB-Dm (∆ D x,(AAA-AXB,Dm) ) and AXB-Dw vs AXB-Dm (∆ D x,(AXB,Dw-AXB,Dm) ) were 1.94% [1.27%, 2.64%] and 1.95% [1.56%, 2.27%], respectively. For the spinal cord and heart, there were obvious differences between the AAA vs AXB-Dm (spinal cord: 1.15%, heart: 2.89%) and AXB-Dw vs AXB-Dm (spinal cord: 1.88%, heart: 3.25%) plans. For the lung, the differences between AAA vs AXB-Dm and AAA vs AXB-Dw were significantly larger than those of AXB-Dm vs AXB-Dw. Compared to the case of AAA and AXB-Dw, the decrease in biologically effective dose (BED 10 , α β = 10 ) of AXB-Dm due to dose non-uniformity exceeded 6.5%, even for a small σ . The average values of equivalent uniform dose in the AAA, AXB-Dw, and AXB-Dm plans were 52.03±.39 Gy, 52.24 ± .81 Gy, and 51.13 ± .47 Gy, respectively. The tumor control probability (TCP) results for PTV in the AAA, AXB-Dw, and AXB-Dm plans were 62.29 ± 1.57%, 62.82 ± 1.69%, and 58.68±1.88%, respectively. With the 2%/2 mm and 3%/3 mm acceptance criteria, the mean values of Δ γ AAA AXB − Dw , Δ γ AAA AXB − Dm , and Δ γ AXB − Dm AXB − Dw were 87.24, 63.3, and 64.81% vs 97.86, 91.77, and 89.25%, respectively. The dose discrepancy between the theoretical calculation and TPS when switching from AXB-Dm to AXB-Dw was approximately 1.63%. Conclusions The AAA and AXB-Dw algorithms overestimated the radiobiological parameters when the tumor particularly consisted of nonuniform tissues. A relatively small dose difference could cause a significant reduction in the corresponding TCP. Dose distribution algorithms should be carefully chosen by physicists and oncologists to improve tumor control, as well as to optimize OARs protection.

(1) Aim: To compare the treatment plans of stereotactic body radiotherapy (SBRT) with CyberKnife (CK) and high-dose-rate (HDR) intracavitary/interstitial brachytherapy (IC/ISBT) and examine the feasibility of CK-SBRT as a viable alternative to BT in patients with locally advanced cervical cancer (LACC). (2) Methods: A BT plan of 28 Gy in four fractions delivered previously to 20 patients with LACC was compared with a CK plan based on the same CT images with structures delineation for BT. The SBRT treatment plan was further divided according to two different approaches, with the high-risk planning target volume (HR-PTV) defined by the high-risk clinical target volume (HR-CTV) without and with a 5 mm margin, which were named CK-CTV plan and CK-PTV plan, respectively. The dose distributions and dosimetric parameters of the target volumes and organs at risk (OARs) were recorded and compared for the three boost plans. Radiobiological metrics were calculated based on the EUD for the hybrid plans. Additionally, the relationship between tumor volume and tolerance doses for the OARs in the BT plan and CK-PTV plan was investigated. (3) Results: Target coverage was better with the CK plan than with the BT plan, as the D95%, D98%, HI and CI of the CK-CTV plan and CK-PTV plan were higher than those of the BT plan; an exception was the D50%. Similarly, the TCP of the target was also significantly in favor of the CK hybrid plans (p < 0.01). For the OARs, the CK-CTV plan was superior to the BT plan as regards the rectum D2cc, bladder D2cc and bladder Dmax. The CK-PTV plan could achieve dosimetric parameters comparable to those of the BT plan for OARs concerning the small residual tumor volume. The NTCP of the rectum for the WPI+CK-CTV plans was significantly lower than that of the WPI+BT plans (p < 0.01). (4) Conclusions: CK-based SBRT can achieve better target coverage, dose sparing for the OARs and radiobiological effects compared with the BT plan for tumors that are not excessively large. CK-based SBRT could be an alternative option to administer a radiation boost for patients with LACC.

BACKGROUND AND PURPOSE:This study aimed to quantify the differences between pre- and post-contrast agent (CA) CT for CyberKnife brain SRS plans. MATERIALS AND METHODS:Twenty-five patients were retrospectively analyzed. They were divided into two categories, inhomogeneous cases (13 patients) and homogeneous cases (12 patients), according to whether the tumor was close to the cavity and inhomogeneous tissues or not. The pre-CA and post-CA plans were designed and calculated using the same monitor unit and paths as those in the ray-tracing algorithm, respectively. RESULTS:The CT number difference of tumor between pre- and post-CA was significant (on average, 24.78 ± 18.56 HU, P-value < 0.01). The deviation value of the target was the largest at approximately 37 HU (inhomo-) and 13 HU (homo-) (P < 0.01), and the values of the organs at risk (OARs) were not statistically significant (P-value > 0.05). However, it was not statistically significant for the dose difference between the two groups with the injection of CA (P-value > 0.05). The absolute effective depth difference generally remained at a level of 1 mm, but the dose difference was quitely fluctuated sometimes more than 20%. The absolute effective depth difference of the inhomo-case (0.62 mm) was larger than that of the homo-case (0.37 mm) on median, as well as the variation amplitude (P-value < 0.05). Moreover, the relative dose differences between the two cases were 0.38% (inhomo-) and 0.2% (homo-), respectively (P-value < 0.05). At the criterion of 1 mm/1%, the gamma pass rate of the homo-case (95.89%) was larger than that of the inhomo-case (93.79%). For the OARs, except for the cochlea, the two cases were almost the same (>98.85%). The tumor control probability of the target was over 99.99% before and after injection of a CA, as well as the results for the homo-case and inhomo-case. CONCLUSIONS:Considering the difference of evaluation indexes between pre- and post-CA images, we recommended plain CT to be employed as the primary image for improving the CK treatment accuracy of brain SRS, especially when the target was close to CA-sensitive OARs and cavity.

Objective:To explore the application value of skin lead marker combined with iSCOUT image-guided positioning system in monitoring and correcting the setup error of intensity-modulated radiotherapy (IMRT) for breast cancer and calculate the PTV margin, aiming to provide reference for clinical practice.Methods:25 breast cancer patients treated with IMRT after modified radical mastectomy in Fujian Medical University Union Hospital from April to August 2019 were enrolled in this study. The skin lead marker combined with iSCOUT image-guided positioning system was employed for image-guided positioning based on the gold standard registration algorithm. Initial setup errors on the x (lateral), y (craniocaudal) and z (anteroposterior) axis and residual errors after the position correction were recorded and analyzed. The effect of the errors before and after image-guided correction upon the plan dose was compared and the reasonable PTV margin was calculated.Results:25 patients received 150 times of positioning verification using skin lead marker combined with iSCOUT image-guided positioning system. The absolute residual errors on the x-, y-and z-axis were (1.53±0.96), (1.30±0.99) and (1.34±0.92) mm, significantly smaller than the initial setup errors of (2.63±2.12), (2.41±2.45) and (3.07±2.77) mm (all P<0.001). The percentage of dose deviation due to residual errors was also smaller than that of the initial errors. Significant differences were observed in D 98%, D 2%, D max of PTV, D max of the heart, D max of the healthy breast, and D mean of the affected lung and both lungs. The percentage deviation from the original plan was decreased from 2.18%, 3.19%, 10.66%, 8.75%, 48.21%, 10.50%, and 3.66% to 0.38%, 0.23%, 2.31%, 0.04%, 13.78%, 6.35% and 0.41%, respectively (all P<0.05). PTV margins on the x-, y-and z-axis after correction were calculated as 1.87, 1.75 and 1.69 mm, respectively. Conclusion:It is feasible and valuable to apply the skin lead marker combined with iSCOUT image-guided positioning system in the positioning verification and correction of breast cancer radiotherapy position, providing novel reference for clinical PTV margin.

目的:利用循环生成对抗网络模型(CycleGAN)进行锥形束CT(CBCT)图像迁移,生成伪CT(sCT)图像,从而实现CBCT图像的HU值矫正.方法:回顾性分析在福建省肿瘤医院行放射治疗的鼻咽癌患者39例,所有患者均接受临床CT与CBCT扫描.以CBCT图像为基准,采用刚性配准算法对临床CT和CBCT进行配准,获得重采样计划CT(pCT).经阈值分割及形态学处理获取配对影像的外轮廓内部区域作为掩膜,对配对影像进行掩膜操作及归一化预处理.建立CycleGAN神经网络,训练sCT生成模型.基于体素点计算平均绝对误差(MAE)和平均误差(ME),用于比较测试集sCT与pCT之间的差异.结果:测试集的sCT图像与pCT图像相比较,在体外轮廓内的MAE和ME分别为(99.00±15.37)HU和(-24.00±12.64)HU;软组织区域的MAE和ME分别为(48.00±7.45)HU和(-7.00±8.96)HU.结论:CycleGAN能修正CBCT图像的HU值,迁移生成的sCT图像具有与pCT图像近似的HU值及平滑性,可用于放射治疗剂量计算.

目的 设计并实现图像引导放疗误差分析虚拟仿真教学培训系统,提高放疗工作人员及相关专业学生的操作技能,进一步推动精准放疗的发展.方法 借助unity 3D构建VR场景模型、C#语言和vs2017编译器进行编程,对立体定向放射治疗图像验证过程进行虚拟仿真设计,注重VR场景构建、学习提示、答题考核、虚拟软件页面及动作触发设计等内容的研发,分为教学模式和考核模式.采用线上评分系统记录使用情况,并上传到"实验空间"进行测试反馈,设计调查问卷分析系统的应用价值.结果 完成系统的开发,从2019年11月上线截至2020年7月,实验浏览量14985人次,实验测试489人次,实验通过率86.7％.回收实验应用价值调查有效问卷84份,其中90.47％的人认为图像引导放射治疗虚拟仿真教学培训系统的开发是有必要的,90.48％的人觉得能掌握知识点.结论 应用虚拟仿真技术对图像引导放疗误差分析系统进行设计研发,具有可行性及应用价值,值得推广.

Objective:To develop a remote training system for CT simulation positioning of radiotherapy using virtual reality technology, and to explore a new method of medical training.Methods:The 3DMax and Maya were employed to establish the 3D model. The unity3D engine was adopted to develop 3D virtual operation and interaction system. Java spring MVC architecture was utilized as the system background service. MySQL was used as the background database system. The users were assigned into two roles: teacher and student, and the modes were divided into teaching and assessment modes.Results:The function of the system covered the whole process of CT simulation positioning, mainly including modules of patient information management, CT simulation positioning machine cognition, body position fixation technology, CT positioning scanning, and emergency handling, etc. Since it was put into use in 2018, the system has been running stably, with 14 920 pages views and an 86.66% pass rate. Compared with the traditional training, the training efficiency has been significantly improved and has received unanimous recognition.Conclusions:The remote training system can effectively improve the clinical practice ability and humanistic care ability of the trainees, which has good autonomy, sharing, and innovation. At present, the system has been put online and has strong popularization with prospects for broad application.

PURPOSE:To research the fiducial-based, real-time tracking intrafraction (during the fraction [intra-]) and interfraction (between fractions [inter-]) tumor respiration amplitude, motion trajectory, and prediction error and quantify their relationships for different types of motion trajectories during Cyberknife-based stereotactic ablation radiotherapy.METHODS AND MATERIALS:Twelve patients with liver tumors were treated using a Cyberknife system, and 58 fractions were involved in this study. Real-time target motion tracking data were extracted and transformed from the robot coordinate system into the patient coordinate system by the rotation matrix. Only the time sessions of the beam on were studied according to the data information generated from the Cyberknife motion tracking system. The motion correlation model between the external marker signal and internal fiducial position was built to present the type of motion trajectory.RESULTS:Using the correlation model as a function of external marker signal and internal fiducial position, we knew 4 motion trajectories mainly existed for liver cancer patients as follows: perfect linearity (group I), simple linearity (group II), hysteresis (group III), and area respiratory (group IV) patterns. More than half of the patients had a linear breathing trajectory. Analyzing all patients together, the intra-amplitudes were slightly less than those of the inter-amplitudes. The amplitude from large to small was in the superior-inferior, left-right and anterior-posterior directions, regardless of inter- and intra-amplitudes. Then, patients with a larger peak-to-peak have a larger standard deviation of amplitude and a larger amplitude in all fractions/sessions. The prediction errors of the linear motion trajectory were generally less than 1 mm. The prediction errors of the regular hysteresis breathing model were smaller than those of the irregular hysteresis model. Scattered breathing would result in a larger tracking error, such as the area respiratory trajectory. It was logical that prediction errors were larger for patients who showed much variation in their breathing amplitude.CONCLUSIONS:This paper showed that the liver motion trajectory model included perfect linearity, sample linearity, hysteresis, and area. The linear motion trajectory presented the minimum tracking error and the best stability, and the hysteresis and area trajectory were the worst. Therefore, breathing management, including respiration training, control, and evaluation of motion trajectory in all directions, was significantly necessary during liver SABR treatment.

目的 动态监测恶性肿瘤患者Cyberknife大剂量分割放射治疗后外周血髓系抑制细胞(MDSCs)和调节性T细胞(T regs)的变化.方法 收集25例(152个样本)Cyberknife立体定向放射治疗恶性肿瘤患者放疗前(Before RT)、放疗结束(After RT)、放疗后1周(After 1W)和放疗后1月(After 1M)外周血标本,并在CT/MR图像上测量Before RT组和After 1M组肿瘤最大直径.流式细胞术检测CD11b+CD33+HLA-DR-/low MDSCs在单核细胞中所占比率和CD4+CD25+CD127-/low Tregs占外周血CD4+细胞的百分比;分析MDSCs和Tregs在不同时间点的变化和两者之间的相关性;以实体瘤疗效评价标准评估疗效.结果 MDSCs和Tregs所占比率(％):Before RT组(4.12±1.22)％ 和(8.57±3.72)％,After RT组(4.05±1.39)％ 和(8.27±3.68)％,After 1W组(3.82±0.79)％ 和(7.97±3.67)％,After 1M组(4.60±1.37)％ 和(11.16±3.67)％.外周血中的MDSCs和Tregs在Cyberknife大分割放疗后减少,1周后最低,1月后急剧增加,高于放疗前.组间配对样本t检验:After 1M组分别与Before RT组(MDSCs P=0.046,Tregs P=0.005)和After 1W组(MDSCs P=0.011,Tregs P=0.024)比较,差别有统计学意义.Before RT与After RT组之间变化MDSCs和Tregs呈正相关(P=0.032).实体瘤疗效评价标准:稳定患者12例(48％),部分缓解患者10例(40％),完全缓解患者1例(4％),进展患者2例(8％).Spearman相关性分析:Before RT组与After 1M组的肿瘤最大直径变化与After 1M组的MSDCs水平呈负相关(P=0.040).结论 Cyberknife可作为大剂量分割模型治疗恶性肿瘤;立体定向放射治疗影响恶性肿瘤患者外周血中MDSCs和Tregs的变化,动态监测MDSCs和Tregs可能在评价恶性肿瘤患者机体免疫抑制状态和最佳免疫干预时间点选择方面具有潜在的临床应用价值.

Objective To analyze the effect of the new conformal index(nCI)and the conventional conformal index(CI)on the treament planning quality of lung stereotopic radiotherapy(SBRT).Methods A total of 19 peripheral lung cancer patients,treated with SBRT in Fujian Medical University Union Hospital from 2014 to 2017,were analyzed retrospectively.Each patient was planned twice yielding identical CI and nCI.The prescription to 95％of planning target volume(PTV)was 48 Gy in four fractions,and renormalization was performed when needed for nineteen nCI plans.The Wilcoxon signed-rank test was used to examine the dosimetric index.Results The dose conformity plots indicate that nCI does not only reflect the dose to the organ at risk outside tumor,but also represents the dose distribution in the PTV.In addition,nCI was stricter with treatment planning qualities when the dose around PTV was closer to the prescribed dose.The value of target coverage(TC),the ratio of out-of-target volumes receiving 105％prescribed dose to the target volume(R105％),the ratio of volume covered by 50％isodose line to the target volume(R50％),and the ipsilateral lung V20were 98.70％,0.56,5.53,15.59％in the CI plans,vs.90％,0,4.99,14.42％in the corresponding nCI plans,respectively.All index were significantly lower in the nCI group(Z ＝-3.823,-3.180,-3.823,-3.783,respectively,P＜0.05).The ratio of the maximum dose to the 2 cm external margin from the PTV(D2 cm)to the maximum dose to the PTV were 63.70％and 64.07％respectively in the two groups,and the differences were not statistially significant(P＞0.05).The conformity values denoted a clinically favorable value as 1 between D95％and D99％of nCI plans,yet were not applicable to CI plans.Conclusions It is more clinically relavant to evaluate lung SBRT plans using nCI,TC and other indicators collectively than using CI alone.

目的:探讨三维静态调强放射治疗计划的子野机器跳数(MU)与加速器实际输出的MU存在的误差,为计划设计时最小跳数的设置提供参考.方法:选择50例调强放射治疗计划,子野数共4 842个.对治疗计划每个子野输出的MU(PDM)与实际加速器出束时每个子野的MU(ADM)进行统计学分析,判断两者的误差情况.结果:计划PDM与ADM的平均值存在显著差异(P＜0.05);当PDM值较小时,PDM与ADM的相对误差概率大大增加,最高达16.33％.结论:PDM与ADM之间存在的误差临床上不可忽视.在不影响计划剂量分布的前提下,当误差可接受在5％内时,建议PDM应该大于8.49 MU;当可接受误差在3％内时,建议PDM应大于14.46 MU.

Journal of Medical Physics ¦ Volume 42 ¦ Issue 2 ¦ April-June 2017 100 We highly appreciate your comments. It is well known that there are considerable target position uncertainties during breast radiotherapy. These uncertainties result from respiratory motions, tissue and organ deformation, daily patient setup, and other causes. Respiratory gating and breath control can reduce the target position uncertainties. However, these techniques are not thoroughly implemented at each hospital, including the authors’ institutions. In our manuscript,[1] we proposed hybrid plans (three-dimensional conformal radiotherapy [3DCRT] + intensity-modulated radiation therapy [IMRT] or 3DCRT + volumetric modulated arc therapy [VMAT]) solely for simultaneous integrated boost treatment delivery. As indicated in the manuscript, “The rationale of using two coplanar 90° arcs in the hybrid VMAT technology is as follows: (1) In the VMAT plan, two arcs are needed to optimize dose distribution when dealing with a complex target; (2) the target is an arc that was nearly 90° along the chest wall, and the 90° arc in tangential direction enters the target without irradiating much of the lung.” In the left breast irradiation, the target dose inhomogeneity and doses to the organs at risk (OAR), especially the heart, ipsilateral lung, and contralateral breast, are the major limitations of 3DCRT.[2] IMRT is capable of improving dose homogeneity and conformity and sparing normal tissues.[3-5] Some oncologists illustrate that VMAT has better protection for the adjacent organs than IMRT.[6-8] In our study, the contribution of IMRT/VMAT is only 30% of the prescribed dose, and 3DCRT delivers 70% of dose in the hybrid plan. For this reason, the hybrid plans of 3DCRT + VMAT result in higher doses to OARs than pure VMAT plans. The 3DCRT portals take into account target position uncertainties; meanwhile, target dose uniformity and normal tissue doses are addressed by the IMRT/VMAT fields. As shown in the manuscript, the hybrid VMAT plans have some dosimetric advantages over previously proposed 3DCRT + IMRT plans. Where respiratory gating or breath control is not implemented, the hybrid plans may be considered for patients who underwent breast-conserving surgery.

This study demonstrated the feasibility and advantages of a hybrid, volumetric arc therapy technique that used two 90° coplanar arcs and two three-dimensional conformal tangential beams in the simultaneous-integrated boost radiotherapy of left-sided breast cancer after breast-conserving surgery. A total of nine patients with stage I, left-sided breast cancer who underwent breast-conserving surgery were selected for this retrospective study. For each patient, a hybrid arc plan was generated and then compared with two hybrid intensity-modulated radiotherapy plans. All plans were optimized using the same objectives and dose constraints. The prescription dose was 50.4 Gy to the planning target volume with simultaneous boost to 60 Gy to the expanded gross target volume in 28 fractions. The differences among these hybrid plans were analyzed by the Kolmogorov–Smirnov test or the Wilcoxon rank sum test. The hybrid arc plans achieved the clinical requirements of target dose coverage and normal tissue (NT) dose constraints. It was found that the hybrid arc plans showed advantages in the conformity index of the expanded gross target volume, the V5of the heart, the D2of the left ventricle, and the D2and V50.4of NTs. The average beam-on time and monitor units of the hybrid arc plans were significantly lower (P < 0.001).

AbstractThe three‐dimensional dose (3D) distribution of intensity‐modulated radiation therapy (IMRT) was verified based on electronic portal imaging devices (EPIDs), and the results were analyzed. Thirty IMRT plans of different lesions were selected for 3D EPID‐based dose verification. The gamma passing rates of the 3D dose verification‐based EPID system (Edose, Version 3.01, Raydose, Guangdong, China) and Delta4 measurements were then compared with treatment planning system (TPS) calculations using global gamma criteria of 5%/3 mm, 3%/3 mm, and 2%/2 mm. Furthermore, the dose–volume histograms (DVHs) for planning target volumes (PTVs) as well as organs at risk (OARs) were analyzed using Edose. For dose verification of the 30 treatment plans, the average gamma passing rates of Edose reconstructions under the gamma criteria of 5%/3 mm, 3%/3 mm, and 2%/2 mm were (98.58 ± 0.93)%, (95.67 ± 1.97)%, and (83.13 ± 4.53)%, respectively, whereas the Delta4 measurement results were (99.14% ± 1.16)%, (95.81% ± 2.88)%, and (84.74% ± 7.00)%, respectively. The dose differences between Edose reconstructions and TPS calculations were within 3% for D95%, D98%, and Dmean in each PTV, with the exception that the D98% of the PTV‐clinical target volume (CTV) in esophageal carcinoma cases was (3.21 ± 2.33)%. However, the larger dose deviations in OARs (such as lens, parotid gland, optic nerve, and spinal cord) can be determined based on DVHs. The difference was particularly obvious for OARs with small volumes; for example, the maximum dose deviation for the lens reached (−6.12 ± 5.28)%. A comparison of the results obtained with Edose and Delta4 indicated that the Edose system could be applied for 3D pretreatment dose verification of IMRT. This system could also be utilized to evaluate the gamma passing rate of each treatment plan. Furthermore, the detailed dose distributions of PTVs and OARs could be indicated based on DVHs, providing additional reliable data for quality assurance in a clinic setting.

选取2014年12月-2016年1月期间我院收治的2型糖尿病合并高脂血症患者66例,采用随机数字表法分为观察组(n=33)和对照组(n=33),在两组患者均进行常规治疗的基础上,对照组患者给予维生素E治疗,观察组给予吡格列酮治疗.分析比较两组患者治疗前后的空腹血糖(FPG)、餐后两小时血糖(2hPG)、糖化血红蛋白(HbA1C)、甘油三酯(TG)、血清总胆固醇(TC)、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)水平变化.结果:治疗前,两组患者的各项指标比较无统计学意义(P＞0.05);治疗后,观察组患者的FPG、2hPG、HbA1C、TG、LDL-C水平显著下降,HDL-C水平显著升高,对照组患者的FPG、2hPG、HbA1C水平显著下降,差异有统计学意义(P＜0.05);观察组患者的FPG、2hPG、HbA1C、TG、LDL-C水平低于对照组,HDL-C水平高于对照组,差异有统计学意义(P＜0.05).结论:吡格列酮治疗2型糖尿病合并高脂血症能显著降低患者血糖水平,调节血脂,疗效显著,值得临床推广应用.

Objective To establish a physical model and optimize its physical parameters using the electronic portable imaging device ( EPID) three-dimensional dose verification system, and to prepare it for clinical application. Methods EPID was used to acquire images of 3, 5, 10, 15, 20, and 25 cm square fields for construction of a physical model. The parameters of the physical model were optimized based on the percentage depth dose, total scatter factor, and off-axis ratio at a depth of 10 cm in a homogeneous water phantom. A thimble ionization chamber and radiochromic films were used to measure the point and planar doses for single fields, combined fields, and IMRT plans in a homogenous phantom and a human phantom. The results were compared with those in the three-dimensional reconstruction. In the human phantom and 10 intensity-modulated radiotherapy ( IMRT) plans for tumors in different sites, the passing rates under the criteria of 5%/3 mm and 3%/3 mm were compared between three-dimensional reconstruction and treatment planning system ( TPS) calculation. The dose and volume analyses were performed on target volume and organs at risk ( OARs) in patients. Results For the single fields, combined fields, and IMRT plans, the mean deviations of point dose were less than 0. 5% between three-dimensional reconstruction and ionization chamber measurement, and less than 2. 0% between three-dimensional reconstruction and TPS calculation. In the homogenous phantom, the human phantom, and patients, the mean passing rates of both two-and three-dimensional doses were higher than 95% under the criteria of 5%/3 mm and 3%/3 mm. In patients, however, OARs with small volume had relatively large dose deviations. Conclusions A series of pre-clinical tests show that the three-dimensional dose verification system is an effective approach for clinical dose verification and holds promise for clinical application.

Objective To investigate the dosimetric performance of two algorithms for correcting the presence of tissue inhomogeneities,the finite site pencil beam (FSPB) and X-ray voxel Monte Carlo (XVMC) plans were implemented in the MONACO system,with the accuracy of application to clinic treatment of two algorithms were evaluated.Methods In a non-uniform artificial anthropomorphic phantom,regular open fields and intensity modulation radiated therapy (IMRT) plans of the MONACO were measured by using calibrated EBT2 films,and the dose accuracy of the two kinds of plans was analyzed by comparing the planned and measured plane dose.Results In an anthropomorphic phantom,the deviations between the calculated values by XVMC and the measured values by films were less than ± 2％.While the deviations of FSPB values between calculation and measurements was within ± 3％,except at the condition of 15 MV,10 cm ×2 cm field,the dose error in lung was up to 6.51％.The verification of individual IMRT beams based on films showed that the pass rates of calculation by XVMC and FSPB were larger than 90％ with γ criterion of 3％/3 mm and 4％/4 mm,respectively.At 3％/3 mm,the pass rates of FSPB were in the range of 80％-90％.At the same time,the pass rates of all individual fields were higher than 90％.Conclusions The accuracy of dose calculation of XVMC is better than that of FSPB when being in multi-segments and non-uniform media.The error of algorithm can be controlled within ±3％,for the calculation by XVMC.And the dose deficiency of PTV arising from algorithm can be avoided.

Objective To realize the PID (Proportional-Integral-Derivative) control of the neonatal incubator.Methods The PID-controlled approximate mathematical model was established with utilization of simple experimental conditions. And then the Matlab software was applied to realize the systematic PID control according to the traditional PID tuning method.Results PID control of the temperature in the neonatal incubator was realized. Conclusion PID control of the temperature in the neonatal incubator played a signiifcant role in ensuring the high precision, stability and security of the instrument.