BACKGROUND AND PURPOSE:Respiratory movement has an important impact on the radiotherapy for lung tumor. Respiratory gating technology is helpful to improve the accuracy of target delineation. This study investigated the value of prospective and retrospective respiratory gating simulations in target delineation and radiotherapy plan design for solitary pulmonary tumors (SPTs) in radiotherapy. METHODS:The enrolled patients underwent CT simulation with three-dimensional (3D) CT non gating, prospective respiratory gating, and retrospective respiratory gating simulation. The target volumes were delineated on three sets of CT images, and radiotherapy plans were prepared accordingly. Tumor displacements and movement information obtained using the two respiratory gating approaches, as well as the target volumes and dosimetry parameters in the radiotherapy plan were compared. RESULTS:No significant difference was observed in tumor displacement measured using the two gating methods (p > 0.05). However, the internal gross tumor volumes (IGTVs), internal target volumes (ITVs), and planning target volumes (PTVs) based on the retrospective respiratory gating simulation were larger than those obtained using prospective gating (group A: pIGTV = 0.041, pITV = 0.003, pPTV = 0.008; group B: pIGTV = 0.025, pITV = 0.039, pPTV = 0.004). The two-gating PTVs were both smaller than those delineated on 3D non gating images (p < 0.001). V5Gy, V10Gy, V20Gy, V30Gy, and mean lung dose in the two gated radiotherapy plans were lower than those in the 3D non gating plan (p < 0.001); however, no significant difference was observed between the two gating plans (p > 0.05). CONCLUSIONS:The application of respiratory gating could reduce the target volume and the radiation dose that the normal lung tissue received. Compared to prospective respiratory gating, the retrospective gating provides more information about tumor movement in PTV.

Purpose:Accurate lesion segmentation is a prerequisite for radiomic feature extraction. It helps to reduce the features variability so as to improve the reporting quality of radiomics study. In this research, we aimed to conduct a radiomic feature reproducibility test of inter-/intra-observer delineation variability in hepatocellular carcinoma using 3D-CT images, 4D-CT images and multiple-parameter MR images.Materials and Methods:For this retrospective study, 19 HCC patients undergoing 3D-CT, 4D-CT and multiple-parameter MR scans were included in this study. The gross tumor volume (GTV) was independently delineated twice by two observers based on contrast-enhanced computed tomography (CECT), maximum intensity projection (MIP), LAVA-Flex, T2W FRFSE and DWI-EPI images. We also delineated the peritumoral region, which was defined as 0 to 5 mm radius surrounding the GTV. 107 radiomic features were automatically extracted from CECT images using 3D-Slicer software. Quartile coefficient of dispersion (QCD) and intraclass correlation coefficient (ICC) were applied to assess the variability of each radiomic feature. QCD<10% and ICC≥0.75 were considered small variations and excellent reliability. Finally, the principal component analysis (PCA) was used to test the feasibility of dimensionality reduction.Results:For tumor tissues, the numbers of radiomic features with QCD<10% indicated no obvious inter-/intra-observer differences or discrepancies in 3D-CT, 4D-CT and multiple-parameter MR delineation. However, the number of radiomic features (mean 89) with ICC≥0.75 was the highest in the multiple-parameter MR group, followed by the 3DCT group (mean 77) and the MIP group (mean 73). The peritumor tissues also showed similar results. A total of 15 and 7 radiomic features presented excellent reproducibility and small variation in tumor and peritumoral tissues, respectively. Two robust features showed excellent reproducibility and small variation in tumor and peritumoral tissues. In addition, the values of the two features both represented statistically significant differences among tumor and peritumoral tissues (P<0.05). The PCA results indicated that the first seven principal components could preserve at least 90% of the variance of the original set of features.Conclusion:Delineation on multiple-parameter MR images could help to improve the reproducibility of the HCC CT radiomic features and weaken the inter-/intra-observer influence.

目的 比较不同模态图像下(3DCT、4DCT和多参数MR)原发性肝癌靶区勾画的差异,并在此基础上分别制定逆向调强放疗计划,比较靶区和肝脏正常组织的剂量学参数,以期寻找最佳的肝癌靶区勾画图像.方法 回顾性选取2019-12-01-2021-03-31山东省肿瘤医院15例已行放疗的原发性肝癌患者模拟定位数据.由同一位高年资影像医师分别在3DCT图像、4DCT图像中的最大密度投影(MIP)图像和多参数MR图像上勾画大体肿瘤体积(GTV),分别命名为GTV-3D、GTV-4D和GTV-MR.然后由另一位高年资放疗医师对靶区进行确认,在2人意见不一致的情况下经共同商榷确定最后的勾画结果.将GTV-MR边界均匀外扩5 mm得到计划靶区体积(PTV)-MR.以PTV-MR为基准,对GTV-3D和GTV-4D分别外扩若干毫米,得到PTV-3D和PTV-4D,使得95％体积的PTV-MR被PTV-3D和PTV-4D覆盖.针对以上3个靶区,由同一位计划经验丰富的高年资物理师采用Varian Eclipse计划系统设计逆向调强计划.计算不同靶区体积,使用戴斯相似性系数(DSC)评估2个靶区之间的相似程度.计划评价指标包括靶区适形指数和均匀指数,靶区剂量D2％、D98％、Dmean及肝脏正常组织受量.结果 GTV-3D、GTV-4D和GTV-MR靶区中位体积分别为8.81、10.28和13.89 cm3;要保证95％体积的PTV-MR被PTV-3D和PTV-4D覆盖,GTV-3D、GTV-4D边界需分别外扩12和10 mm.PTV-3D、PTV-4D和PTV-MR靶区中位体积分别为69.53、62.79和54.53 cm3.PTV-3D和PTV-4D的DSC最大,为0.68;PTV-3D和PTV-MR的DSC最小,为0.44.所有计划靶区均能达到临床要求,不同计划之间的靶区剂量学参数总体差异无统计学意义,均P>0.05.肝脏正常组织中位平均剂量在PTV-3D计划、PTV-4D计划和PTV-MR计划中分别为15.97、12.89和11.97 Gy,总体差异有统计学意义,H=12.57,P=0.029.结论 不同模态影像勾画的原发性肝癌靶区差异较大,基于多参MR勾画的PTV体积小于基于3DCT和4DCT勾画的PTV体积.基于多参MR有可能会缩小肝癌靶区外扩边界,降低肝脏正常组织受量,建议在原发性肝癌放疗靶区勾画时尽可能地参考多参MR影像学信息.

Objective:To explore the feasibility of low-dose 4DCT scanning in simulation and target delineation for solitary pulmonary tumors (SPTs).Methods:23 patients with SPTs received 4DCT scanning simulation with the conventional scanning (CON), low voltage (LV), low current (LA) and low voltage combined with low current (LVA) in sequence. Based on the 4DCT images derived from the four sets of scanning parameters, the internal gross tumor volume (IGTV CON, IGTV V, IGTV A, IGTV VA) of SPTs were delineated and matched. Taking IGTV CON as reference, the tumor displacement and the centroid position of IGTV V, IGTV A and IGTV VA were compared with IGTV CON. The radiation doses under different scanning parameters were compared. Results:The volumes of IGTV CON, IGTV V and IGTV A were (12.26±12.30) cm 3, (12.21±12.16) cm 3 and (11.87±11.70) cm 3, respectively ( P=0.337). IGTV VA was (11.34±11.07) cm 3, significantly smaller than IGTV CON ( P=0.005). There was no significant difference in the centroid positions of IGTV CON, IGTV V, IGTV A and IGTV VA in three directions ( P=0.491, 0.360, 0.136). The Dice′s similarity coefficient (DSC VA) was significantly lower than DSC V and DSC A ( P=0.004, 0.030). The tumor displacement measured by the four sets of 4DCT images was similar in the LR direction ( P=0.470), and also in the AP direction ( P=0.108). For the displacement in the SI direction, LVA scanning was smaller than CON ( P=0.015). The radiation doses under four different scanning conditions were (397.0±140.3) mGy·cm, (175.0±61.8) mGy·cm, (264.8±95.3) mGy·cm and (116.8±41.2) mGy·cm, respectively ( P<0.001). Conclusions:LV or LA scanning exert no significant effect on the volume, centroid position of IGTV and the tumor displacement in 4DCT simulation for SPTs. The radiation dose that patients receive under LV and LV scanning is lower than that of CON. Consequently, LV or LA scanning is feasible in 4DCT simulation and target delineation for SPTs.

目的 探讨基于3DCT定位的乳腺癌保留乳房术后部分乳腺外照射(EB-PBI)调强放疗计划与4DCT模拟患者实际呼吸运动过程中靶区、危及器官(OARs)的剂量以及肿瘤控制概率(TCP)、正常组织并发症概率(NTCP)的差异.方法 纳入山东省肿瘤医院2016-06-12-2021-05-10收治的30例女性乳腺癌患者,基于3DCT图像和4DCT图像10个时相分别进行靶区勾画.基于3DCT图像进行EB-PBI放疗计划设计.然后将基于3DCT的EB-PBI计划(Plan-3D)分别配准到4DCT图像的0～90％10个相位上,将10个相位的计划基于0相位累加,得到4D累加计划Plan-4D.将Plan-3D和Plan-4D进行计划比较,并以Lyman-Kutcher-Burman(LKB)模型预测TCP和NTCP.结果 Plan-4D的临床靶区体积(CTV)、计划靶区体积(PTV)、D90、D95、Dmean、V90、V95均大于Plan-3D,差异均有统计学意义,Z=-4.783,P<0.001;Z=-4.615,P<0.001;Z=-4.720,P<0.001;Z=-4.741,P<0.001;Z=-3.569,P<0.001;Z=4.415,P=0.019;Z=-3.774,P<0.001.Plan-4D患乳同侧肺体积、V5、Dmean,患乳对侧肺体积、V5、Dmean和心脏体积均大于Plan-3D,差异均有统计学意义,Z=-4.679,P<0.001;Z=-4.782,P<0.001;Z=-4.638,P<0.001;Z=-4.103,P<0.001;Z=-2.223,P=0.026;Z=-3.137,P=0.002.左乳患者心脏的V5、V10、Dmean在Plan-4D时高于Plan-3D,差异有统计学意义,Z=-2.215,P=0.027;Z=-4.638,P<0.001;Z=-3.317,P=0.002.右乳患者心脏的V5、V10在Plan-4D时高于Plan-3D,差异均有统计学意义(Z=-3.296,P=0.001;Z=-2.660,P=0.008),二者Dmean差异无统计学意义,Z=-1.903,P=0.057.而Plan-3D的TCP高于Plan-4D,Plan-3D同侧肺的NTCP同样高于Plan-4D,差异均有统计学意义,Z=-4.782,P<0.001;Z=-4.477,P<0.001.结论 基于3DCT的静态计划会高估靶区剂量覆盖、TCP和患乳同侧肺的NTCP,而低估OARs的受照剂量.基于4DCT的EB-PBI动态累加计划更接近真实放疗过程,能够用于精确放疗剂量体积参数的准确评估.

ObjectivesTo investigate the tumor volume and its change on short-term outcome in esophageal squamous cell carcinoma (ESCC) patients who underwent definitive radiotherapy or chemoradiotherapy.Methods and MaterialsAll data were retrospectively collected from 418 ESCC patients who received radiotherapy or chemoradiotherapy at our institution between 2015 and 2019. Short-term outcome using the treatment response evaluation was assessed according to the RECIST 1.1. The tumor volume change rate (TVCR) was defined as follows: TVCR = {1 − [gross tumor volume (GTV) at shrinking irradiation field planning)]/(GTV at the initial treatment planning)} ×100%. Chi square test was used to compare the clinic characteristics in different TVCR groups, and the difference between initial GTV (GTVi) and shrinking GTV (GTVs) was compared using Wilcoxon’s sign rank test. Logistic regression analysis and Spearman correlation was performed.ResultsThere was a significant decrease in GTVi compared to GTVs (P < 0.001). In univariate analysis, age, cT-stage, TNM stage, treatment modality, GTVi, and TVCR were associated with short-term outcome (all P< 0.05). In multivariate analysis, gender and TVCR were statistically significant (P = 0.010, <0.001) with short-term outcome, and the combined predictive value of gender and TVCR exceeded that of TVCR (AUC, 0.876 vs 0.855).ConclusionsTVCR could serve to forecast short-term outcome of radiotherapy or chemoradiotherapy in ESCC. It was of great significance to guide the individualized treatment of ESCC.

Abstract Background Perfusion CT can offer functional information about tumor angiogenesis, and 18F-FDG PET/CT quantifies the glucose metabolic activity of tumors. This prospective study aims to investigate the value of biologically relevant imaging biomarkers for predicting treatment response and survival outcomes in patients with locally advanced esophageal squamous cell cancer (LA ESCC). Methods Twenty-seven patients with pathologically proven ESCC were included. All patients had undergone perfusion CT and 18F-FDG PET/CT using separate imaging systems before receiving definitive chemoradiotherapy (dCRT). The perfusion parameters included blood flow (BF), blood volume (BV), and time to peak (TTP), and the metabolic parameters included maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG). The flow-metabolism ratio (FMR) was defined as BF divided by SUVmax. Statistical methods used included Spearman’s rank correlation, Mann–Whitney U test or two-sample t test, receiver operating characteristic (ROC) curve analysis, the Kaplan–Meier method, and Cox proportional hazards models. Results The median overall survival (OS) and progression-free survival (PFS) were 18 and 11.6 months, respectively. FMR was significantly positively correlated with BF (r = 0.886, p < 0.001) and negatively correlated with SUVmax (r = − 0.547, p = 0.003) and TTP (r = − 0.462, p = 0.015) in the tumors. However, there was no significant correlation between perfusion and PET parameters. After dCRT, 14 patients (51.9%) were identified as responders, and another 13 were nonresponders. The BF and FMR of the responders were significantly higher than those of the nonresponders (42.05 ± 16.47 vs 27.48 ± 8.55, p = 0.007; 3.18 ± 1.15 vs 1.84 ± 0.65, p = 0.001). The ROC curves indicated that the FMR [area under the curve (AUC) = 0.846] was a better biomarker for predicting treatment response than BF (AUC = 0.802). Univariable Cox analysis revealed that of all imaging parameters, only the FMR was significantly correlated with overall survival (OS) (p = 0.015) and progression-free survival (PFS) (p = 0.017). Specifically, patients with a lower FMR had poorer survival. Multivariable analysis showed that after adjusting for age, clinical staging, and treatment response, the FMR remained an independent predictor of OS (p = 0.026) and PFS (p = 0.014). Conclusions The flow-metabolism mismatch demonstrated by a low FMR shows good potential in predicting chemoradiotherapy sensitivity and prognosis in ESCC.

Objective:To measure the displacement of the solitary pulmonary lesion (SPL) located in different pulmonary segments based on 4D-CT technology (4DCT) and to establish and verify a relevant mathematical model of tumor displacement.Methods:The modeling samples of 290 SPLs were subject to both 4DCT and active breath control (ABC) spiral CT scans. The tumor displacement in different pulmonary segments was measured based on 4DCT images. The tumor volume was obtained by contouring the gross tumor volume (GTV) on ABC spiral CT images. The diaphragm movement was measured by X-ray simulator. The vital capacity and tidal volume were gained by pneumatometer. The baseline data, such as gender, age, height, weight, respiratory rate, and tumor lobe and segment where tumors were located, were collected. Multivariate linear regression was used to analyze the correlation between the 3D-tumor displacement and gender, age, height, weight, respiratory rate, tumor location, volume and diaphragm movement. The displacement model was established based on the modeling sample of 290 cases. Then, it was verified by comparing the tumor displacement derived from the model with that of 4DCT technology based on the randomly selected 17 SPLs.Results:The displacement model for tumors located in the upper lobe was established as Xup=-0.267+0.002TV+0.446DM, Yup=-1.704+0.004TV+0.725DM+2.250SII+1.349SIII and Zup=0.043+0.626DM+0.599SII+0.519SIII. The displacement model of the middle lobe tumors was Xmid=0.539+0.758DM, Ymid=-2.316+2.707DM+0.009TV and Zmid=0.717+1.112DM. The displacement model for tumors located in the lower lobe was Xlow=-0.425+0.004TV+0.857DM, Ylow=4.691+4.817DM+0.005TV-0.307RR+3.148SIX+2.655SX and Zlow=0.177+0.003TV+0.908DM.(DM: diaphragm movement, TV: tidal volume, RR: respiratory rate, SII: posterior segment, SIII: anterior segment, SIX: lateral basal segment, SX: posterior basal segment). There was no significant difference between two results derived from the displacement model and 4DCT technology.( P>0.05). Conclusions:The diaphragm movement and tidal volume are the main influencing factors of 3D lung tumor displacement. The tumor displacement in the superior-inferior direction is correlated with different pulmonary segments of the upper and lower lobes. The displacement of tumors located in different segments of middle lobes is similar. The displacement model can predict the displacement of SPLs located in different lobes, providing reference for individualized delineation of PTV.

Background To assess the position accuracy of the six-degree-of-freedom (6-DoF) couch based on cone beam computed tomography (CBCT) and exploit the correlation of the six degrees errors. Methods CT scans of an anthropomorphic phantom and patients were obtained at 3 mm slice thicknesses using a Philips scanner at the head, first supine and prostrate positions. An Eclipse Treatment Planning System was used to create a treatment plan. Different levels of known position errors were introduced to simulate patient position status for the anthropomorphic phantom. CBCT datasets for each position were acquired and registered to original CT datasets to evaluate the accuracy of the 6-DoF couch and determine the setup errors of patients. The setup errors of 200 CBCT datasets from 14 patients with pelvic tumors were analyzed. The correlations between six degrees position errors were finally extracted. Results For the phantom study, the difference between known introduced errors and the setup errors were almost negligible. The deviation (mean ± one standard deviation) in registration methods were (0.01±0.02) cm, (0.04±0.075) cm, (0.02±0.004) cm, (0.01±0.04)°, (0.1±0.08)°, (0.03±0.05)° and (0.01±0.01) cm, (0.03±0.007) cm, (0.01±0.01) cm, (0.05±0.06)°, (0.08±0.08)°, (0.04±0.05)° for supine and prone position, respectively. The deviation in positions were (0.07±0.10) cm, (0.16±0.02) cm, (0.08±0.06) cm, (0.54±0.46)°, (0.24±0.16)°, (0.09±0.09)° and (0.06±0.09) cm, (0.19±0.09) cm, (0.09±0.07) cm, (0.49±0.49)°, (0.16±0.08)°, (0.1±0.13)° for bone and soft tissue registration methods, respectively. For patient data, the setup errors were (−0.07±0.22) cm, (0.14±0.35) cm, (−0.12±0.4) cm, (0.79±1.6)°, (0.41±0.71)°, (−0.03±0.8)° for supine position and (0.16±0.27) cm, (0.19±0.48) cm, (−0.05±0.34) cm, (1.1±1.49)°, (0.65±1.00)°, (−0.23±0.75)° for prone position, respectively. There is a significant moderate correlation between the longitudinal and pitch directions and between the vertical and pitch directions when the patient is in the supine position. Conclusions The six-dimensional couch positioning verification system based on CBCT has high accuracy and can meet the requirements of precise radiotherapy for pelvic tumors. There is a certain correlation between translation direction and rotation direction.

To perform a dosimetric evaluation of four different simultaneous integrated boost whole brain radiotherapy modalities with hippocampus and inner ear avoidance in the treatment of limited brain metastases. Computed tomography/magnetic resonance imaging data of 10 patients with limited (1–5) brain metastases were used to replan step-and-shoot intensity-modulated radiotherapy (sIMRT), dynamic intensity-modulated radiation therapy (dIMRT), volumetric-modulated arc therapy (VMAT), and helical tomotherapy (Tomo). The prescribed doses of 40–50 Gy in 10 fractions and 30 Gy in 10 fractions were simultaneously delivered to the metastatic lesions and the whole-brain volume, respectively. The hippocampal dose met the RTOG 0933 criteria for hippocampal avoidance (Dmax ≤17 Gy, D100% ≤10 Gy). The inner ear dose was restrained to Dmean ≤15 Gy. Target coverage (TC), homogeneity index (HI), conformity index (CI), maximum dose (Dmax), minimum dose (Dmin) and dose to organs at risk (OARs) were compared. All plans met the indicated dose restrictions. The mean percentage of planning target volume of metastases (PTVmets) coverage ranged from 97.1 to 99.4%. For planning target volume of brain (PTVbrain), Tomo provided the lowest average D2% (37.5 ± 2.8 Gy), the highest average D98% (25.2 ± 2.0 Gy), and the best TC (92.6% ± 2.1%) and CI (0.79 ± 0.06). The two fixed gantry IMRT modalities (step and shot, dynamic) provided similar PTVbrain dose homogeneity (both 0.76). Significant differences across the four approaches were observed for the maximum and minimum doses to the hippocampus and the maximum doses to the eyes, lens and optic nerves. All four radiotherapy modalities produced acceptable treatment plans with good avoidance of the hippocampus and inner ear. Tomo obtained satisfactory PTVbrain coverage and the best homogeneity index. Clinicaltrials.gov, NCT03414944 . Registered 29 January 2018

Abstract Background Radiation pneumonitis is a common and potentially fatal complication of radiotherapy (RT). Some patients with radiation pneumonitis show increases in uptake of fluorodeoxyglucose (FDG) on positron emission tomography (PET), but others do not. The exact relationship between radiation pneumonitis and 18F-FDG PET findings remains controversial. Methods We used an animal model of radiation pneumonitis involving both radiation and simulated bacterial infection in Wistar rats. Treatment groups (10 rats/group) were as follows: control, RT-only, lipopolysaccharide (LPS)-only, and RT+LPS. All rats had micro-PET scans at 7 weeks after RT (or sham). Histologic, immunohistochemical, and biochemical analyses were performed to evaluate potential mechanisms. Results Irradiated rats had developed radiation pneumonitis at 7 weeks after RT based on pathology and CT scans. Maximum and mean standardized uptake values (SUVmax and SUVmean) at that time were significantly increased in the LPS group (P < 0.001 for both) and the RT+LPS group (P < 0.001 for both) relative to control, but were not different in the RT-only group (P = 0.156 SUVmax and P = 0.304 SUVmean). The combination of RT and LPS increased the expression of the aerobic glycolysis enzyme PKM2 (P < 0.001) and the glucose transporter GLUT1 (P = 0.004) in lung tissues. LPS alone increased the expression of PKM2 (P = 0.018), but RT alone did not affect PKM2 (P = 0.270) or GLUT1 (P = 0.989). Conclusions Aseptic radiation pneumonitis could not be accurately assessed by 18F-FDG PET, but was visualized after simulated bacterial infection via LPS. The underlying mechanism of the model of bacterial infection causing increased FDG uptake may be the Warburg effect.

To explore the relationship between metabolic uptake of the 18F-ALF-NOTA-PRGD2 (18F-RGD) tracer on positron emission tomography/computerized tomography (PET/CT) and the antiangiogenic effect of apatinib in patients with solid malignancies.

Background: To study the feasibility of defining the individual internal gross tumor volume (IGTV) of hepatocellular carcinoma (HCC) using four-dimensional computed tomography (4DCT) imaging and T2-weighted magnetic resonance imaging (T2-weighted MRI) by deformable registration (DR). Methods: Ten HCC patients who previously received radiotherapy treatment were selected for this study. The following simulation images were acquired sequentially: 4DCT in free breathing and T2-weighted MRI in deep-inspiration breath holding. All 4DCT images were sorted into ten phases according to breath cycle (CT00-CT90). Gross tumor volumes (GTVs) were contoured on all CT images and the IGTV was obtained by merging the GTVs in each phase of 4DCT imaging. The GTV on the T2-weighted MRI image was deformably registered to each 4DCT phase image using MIM software version 6.5.6 and the results were labeled with DR subscript. The IGTV(DR) was obtained by merging the GTV(DR) on the 4DCT images. Statistical differences in the GTVs and between the IGTV and IGTV(DR) were assessed by a paired t-test. Results: The edge of most lesions could be definitively identified using T2-weighted MRI images, compared to 4DCT images. The Reg Reveal and Reg Refine were used to minimize the DR error manually within 1 mm. The GTVs after DR on 4DCT different phase imaging increased by an average of 8.18% (P<0.05), while the volume of IGTV(DR) increased by an average of 9.67%, compared to that of IGTV (P<0.05). Conclusions: The use of 4DCT imaging alone has the potential risk of missing a partial volume of HCC. However, T2-weighted MRI images can carry more information than 4DCT image. As such, the combination of 4DCT and T2-weighted MRI images using the DR technique may improve accuracy in the delineation of HCC.

Brain metastases (BM) from cutaneous melanoma are associated with poor prognosis. Population-based data describing the associated factors of incidence and prognosis of BM from melanoma are still lacking. We identified 121 255 melanoma patients diagnosed during 2010–2015 from the Surveillance, Epidemiology, and End Results program, and identified predictive factors for incidence and survival of BM patients by using multivariable logistic and Cox’s proportional hazard regression, respectively. We identified 1547 patients with BM at the time of diagnosis of malignant cutaneous melanoma, representing 1.3% of the entire cohort and 35.4% of the subset with metastatic disease. The characteristics associated with higher BM incidence were male sex, age 40–60 years, melanoma location of face/head/neck, histologic type of nodular, higher T-stage, ulceration and extracranial metastases. The median overall survival and median cutaneous melanoma specific survival of patients with BM was 5 and 6 months, respectively. The relative factors of poor survival were older age and more extracranial metastatic sites. In summary, we provided insight into the epidemiology of BM from cutaneous melanoma. These results may provide significant help to improve the screening strategy of BM strategy and update the existing prognosis evaluation system.

Differences in gross target volume (GTV) and central point positions among moving lung cancer models constructed by CT scanning at different frequencies were compared, in order to explore the effect of different respiratory frequencies on the GTV constructions in moving lung tumors. Eight models in different shapes and sizes were established to stimulate lung tumors. The three-dimensional computed tomography (3DCT) and four-dimensional computed tomography (4DCT) scanning were performed at 10, 15 and 20 times/min in different models. Differences in GTV volumes and central point positions at different motion frequencies were compared by means of GTV3Ds (GTV3D-10, GTV3D-15, GTV3D-20) and IGTV4Ds (IGTV4D-10, IGTV4D-15, IGTV4D-20). Volumes of GTV3D-10, GTV3D-15, GTV3D-20 were 12.41±14.26, 10.38±11.18 and 12.50±15.23 cm3 respectively (P=0.687). Central point coordinates in the x-axis direction were -8.16±96.21, -8.57±96.08 and -8.56±95.73 respectively (P=0.968). Central point coordinates in the y-axis direction were 108.22±25.03, 110.41±22.47 and 109.04±24.24 (P=0.028). Central point coordinates in the z-axis direction were 65.19±13.68, 65.43±13.40 and 65.38±13.17 (P=0.902). The difference was significant in the y-axis direction (P=0.028). Volumes of IGTV4D-10, IGTV4D-15, IGTV4D-20 were 17.78±19.42, 17.43±19.56 and 17.44±18.80 cm3 (P=0.417). Central point coordinates in the x-axis direction were -7.73±95.93, -7.86±95.56 and -7.92±95.14 (P=0.325). Central point coordinates in the y-axis direction were 109.41±24.54, 109.60±24.13 and 109.16±24.28 (P=0.525). Central point coordinates in the z-axis direction were 65.52±13.31, 65.59±13.39 and 65.51±13.34 (P=0.093). However, the central point position of GTV in the head and foot direction by 3DCT scanning was severely affected by the respiratory frequency.

Objective To investigate the feasibility of defining the radiotherapy target of primary liver cancer using four-dimensional computed tomography (4DCT) and T2-weighted magnetic resonance (MR-T2) deformable image registration.Methods Ten patients with hepatocellular carcinoma (HCC) who first received radiotherapy were included in this study.The 4DCT in free breathing and MR-T2 in deep breathing were acquired sequentially.4DCT were sorted into ten series of CT images according to the respiratory phase.MIM software was used for deformable image registration.The accuracy of deformable image registration was assessed by the maximal displacements in three-dimensional directions of the portal vein and the celiac trunk and the degree of liver overlapping (P-LIVER).Gross tumor volume (GTV) was delineated on different series of CT images and the internal GTV (IGTV) was merged by ten GTVs on 4DCT images in each phase.The MR-T2 image was deformably registered to 4DCT images in each phase to acquire ten GTVDR.The IGTVDRwas obtained by merging the ten GTVDR.The differences between different target volumes were compared by paired t-test.Results The maximal displacements in three-dimensional directions of the portal vein were 0.3±0.8 mm along the x-axis, 0.8±1.8 mm along the y-axis, and 0.5±1.5 mm along the z-axis.The maximal displacements in three-dimensional directions of the celiac trunk were 0.1±1.0 mm along the x-axis, 0.7±1.2 mm along the y-axis, and 0.6±2.0 mm along the z-axis.Overlapping degree was 115.4±13.8%.The volumes of GTVs obtained from 4DCT images in each phase after DR increased by an average of 8.18%(P<0.05), and were consistent with those delineated on MR-T2 images.The IGTV after DR increased by an average of 9.67%(P<0.05).Conclusions MRI image can show more information and have a higher contrast than CT image.MRI images should be combined with 4DCT images for delineating the GTV.It can better determine the scope and trajectory of the target and improve the delineation accuracy of HCC target.

Objective To explore the effect of pitch in three-dimensional computed tomography (3DCT)on the gross tumor volume(GTV)and spatial position of solitary pulmonary lesion(SPL), and to evaluate the feasibility of high-pitch 3DCT simulation for SPL. Methods Twenty-two patients with peripheral lung cancer or metastatic SPL were divided into groups A and B according to the tumor location. All patients underwent spiral CT scans at different pitches(pitchCON=0.938, pitchS=0.438, and pitchB=1.188)during free breathing. All GTVSwere delineated by the same radiation oncologist using the same contouring protocol. GTVCONgenerated at pitchCON, GTVSgenerated at pitches, and GTVBgenerated at pitchB were compared in terms of volume and geometric position, and GTVSand GTVBwere registered to GTVCONgained at the conventional pitch. The Friedman M and Wilcoxon rank-rum test were used for comparison. Results The volumes of GTVCON, GTVS, and GTVBwere 11.58± 16.42 cm3, 11.63± 17.73 cm3, and 12.09± 17.46 cm3, respectively(P=0.11). There were no significant differences in the centroid position in x,y,and z directions between GTVCON,GTVS,and GTVB(Px=0.33,Py=0.81, Pz=0.39). The same result was found in group B (Px=0.92,Py=0.05, Pz=0.37). The matching index(MI)between GTVSand GTVCONwas related to the tumor location,so was the MI between GTVBand GTVCON. Conclusions The pitch in 3DCT simulation has no significant effect on the GTV and spatial position of SPL. Increasing CT pitch appropriately can improve the scanning speed and shorten the duration of 3DCT simulation,so high-pitch 3DCT simulation is feasible for SPL.

PURPOSE To explore the impact of different width detector on the volume and geometric position of gross tumor volume (GTV) of the solitary pulmonary lesion (SPL), as well as the impact on scanning time and radiation dose during the simulation. MATERIALS AND METHODS Twenty-three patients with SPL underwent three-dimensional computed tomography (3DCT) simulation using different width detector, followed by four-dimensional computed tomography (4DCT) scans. GTV16 and GTV4 derived from different width detectors were compared with internal gross tumor volume (IGTV) generated from 4DCT on the volume and geometric position. Fourteen patients with lesions located in the upper lobe were defined as Group A and nine patients in the middle or lower lobe were defined as Group B. The scanning time and radiation dose during the simulation with the different width detector were compared as well. RESULTS The volumes of IGTV, GTV16, and GTV4 in Group A were 13.86 ± 14.42 cm3, 11.88 ± 11.93 cm3, and 11.64 ± 12.88 cm3, respectively, and the corresponding volumes in Group B were 12.84 ± 11.48 cm3, 6.90 ± 6.63 cm3, and 7.22 ± 7.15 cm3, respectively. No difference was found between GTV16 and GTV4 in Groups A and B (PA = 0.11, PB = 0.86). Either GTV16 or GTV4 was smaller than IGTV (P16 = 0.001, P4 = 0.000). The comparison of the centroidal positions in x, y, and z directions for GTV16, GTV4, and IGTV showed no significant difference both in Groups A and B (Group A: Px = 0.19, Py = 0.14, Pz = 0.47. Group B: Px = 0.09, Py = 0.90, Pz = 0.90). The scanning time was shorter and radiation dose patient received was lower using 16 × 1.5 mm detector combination than 4 × 1.5 mm detector (P = 0.000). CONCLUSIONS Different width detector had no impact on the volume and geometric position of GTV of SPL during 3DCT simulation. Using wide detector would save time and decrease radiation dose compared with the narrow one. 3DCT simulation using either 16 × 1.5 mm detector or 4 × 1.5 mm detector could not cover all tumor motion information that 4DCT offered under free breathing conditions.

Objective: To explore the relationship between the displacement of the whole breast target and the displacement of a selected skin marker, the nipple and a selected surgical clip using four-dimensional computed tomography (4DCT). Methods and materials: Thirteen breast cancer patients who had undergone breast-conserving surgery were recruited for whole breast intensity-modulated radiotherapy (IMRT), and respiration-synchronized 4DCT image data were gathered during free breathing. The correlation between the displacement of the whole breast and the displacement of the clip, nipple and skin marker were analyzed. The changes in ipsilateral lung volume were analyzed during the respiratory cycle relative to the displacement of the breast. Results: There was no significant difference between the volumes of the whole breast targets at the selected end-inspiration (EI) and end-expiration (EE) phases. No meaningful correlation established between the breast and lung volume variance with the target motion. According to a population-based analysis, the displacement of the whole breast target was only significantly associated with the displacement of the superior clip along the Y-axes (r = 0.657, P = 0.015). Conclusion: The changes in breast and lung volume cannot be used to identify the target displacement. The selected clip in the surgical cavity may serve as a useful surrogate for tracking whole breast target movement during radiotherapy.

Purpose: The purpose of this study was to compare the positional and volumetric differences of internal target volumes defined on three-dimensional computed tomography (3DCT), four-dimensional CT (4DCT), and cone-beam CT (CBCT) images of non-small-cell lung cancer (NSCLC). Materials and methods: Thirty-one patients with NSCLC sequentially underwent 3DCT and 4DCT simulation scans of the thorax during free breathing. The first CBCT was performed and registered to the planning CT using the bony anatomy registration during radiotherapy. The gross tumor volumes were contoured on the basis of 3DCT, maximum intensity projection (MIP) of 4DCT, and CBCT. CTV3D (clinical target volume), internal target volumes, ITVMIP and ITVCBCT, were defined with a 7 mm margin accounting for microscopic disease. ITV10 mm and ITV5 mm were defined on the basis of CTV3D: ITV10 mm with a 5 mm margin in left-right (LR), anterior-posterior (AP) directions and 10 mm in cranial-caudal (CC) direction; ITV5 mm with an isotropic internal margin (IM) of 5 mm. The differences in the position, size, Dice's similarity coefficient (DSC) and inclusion relation of different volumes were evaluated. Results: The median size ratios of ITV10 mm, ITV5 mm, and ITVMIP to ITVCBCT were 2.33, 1.88, and 1.03, respectively, for tumors in the upper lobe and 2.13, 1.76, and 1.1, respectively, for tumors in the middle-lower lobe. The median DSCs of ITV10 mm, ITV5 mm, ITVMIP, and ITVCBCT were 0.6, 0.66, and 0.83 for all patients. The median percentages of ITVCBCT not included in ITV10 mm, ITV5 mm, and ITVMIP were 0.1%, 1.63%, and 15.21%, respectively, while the median percentages of ITV10 mm, ITV5 mm, and ITVMIP not included in ITVCBCT were 57.08%, 48.89%, and 20.04%, respectively. Conclusion: The use of the individual ITV derived from 4DCT merely based on bony registration in radiotherapy may result in a target miss. The ITVs derived from 3DCT with isotropic margins have a good coverage of the ITV from CBCT, but the use of those would result in a high proportion of normal tissue being irradiated unnecessarily.