背景与目的 头颈部肿瘤放疗中,颈部因活动性较大,与头部的相对位置不容易固定.本研究旨在探讨质子重离子治疗中,特制口咬器对颈椎及头颈部固定效果的影响.方法 选取40例鼻咽癌患者,其中20例使用口咬器(口咬器组),另20例不使用口咬器(对照组).治疗前对治疗部位拍摄验证片,分别拍摄200组,与定位电子计算机断层扫描(computed tomography,CT)图像进行配准,对数据进行记录并进行t检验分析.结果 口咬器组与对照组在左右(Lat)、头脚(Long)、背腹(Vert)、偏转角(Iso)、仰俯角(Pitch)、翻滚角(Roll)6个方向上的位移均值(有正负)分别为(-0.5±2.5)mm、(-0.5±2.2)mm,P = 0.48;(0.3±1.9)mm、(-2.6±1.7)mm,P = 0.001;(0.4±1.3)mm、(-1.0±1.3)mm,P = 0.005;(0.44±0.66)°、(0.08±0.53)°,P = 0.08;(-0.02±0.58)°、(-0.63±0.45)°,P = 0.007;(-0.08±0.60)°、(0.16±0.54)°,P = 0.07.在6个方向上的位移绝对值均值(无正负)分别为(2.6±1.7)mm、(2.6±1.7)mm,P = 0.46;(2.2±1.4)mm、(3.2±1.9)mm,P = 0.03;(1.4±1.0)mm、(2.1±1.6)mm,P = 0.047;(0.76±0.50)°、(0.72±0.43)°,P = 0.36;(0.53±0.40)°、(0.88±0.53)°,P = 0.01;(0.54±0.41)°、(0.56±0.43)°,P = 0.38.口咬器组与对照组在左右、头脚、腹背方向≤3 mm,在偏转角、仰俯角、翻滚角方向≤1°的患者占比分别为63.5％、63.5％,P = 0.35;72.5％、61.5％,P<0.001;86.5％、79％,P = 0.07;75.5％、79％,P = 0.06;85.5％、69％,P = 0.04;85.5％、85.5％,P = 0.09.结论 质子重离子治疗中,特制口咬器可提高对颈椎及头颈部的固定效果.

Objectives: To establish and validate a linear model utilizing diaphragm motion (DM) to predict the displacement of liver tumors (DLTs) for patients who underwent carbon ion radiotherapy (CIRT). A total of 60 pairs of planning and reviewing four-dimensional computed tomography (4DCT) sets over 23 patients were used. Method: We constructed an averaged computed tomography (CT) set for each either planning or reviewing 4DCT within respiratory phases between 20% of exhale and inhale. A rigid image registration to align bony structures was performed between planning and reviewing 4DCT. The position changes on top of diaphragm in superior-inferior (SI) direction between 2 CTs to present DM were obtained. The translational vectors in SI from matching to present DLT were obtained. The linear model was built by training data for 23 imaging pairs. A distance model utilized the cumulative probability distribution (CPD) of DM or DLT and was compared with the linear model. We conducted the statistical regression analysis with receiver operating characteristic (ROC) testing data of 37 imaging pairs to validate the performance of our linear model. Results: The DM within 0.5 mm was true positive (TP) with an area under the ROC curve (AUC) of 0.983 to predict DLT. The error of predicted DLT within half of its mean value indicated the reliability of prediction method. The 23 pairs of data showed (4.5 +/- 3.3) mm for trend of DM and (2.2 +/- 1.6) mm for DLT. A linear model of DLT = 0.46*DM + 0.12 was established. The predicted DLT was (2.2 +/- 1.5) mm with a prediction error of (0.3 +/- 0.3) mm. The accumulated probability of observed and predicted DLT with < 5.0 mm magnitude was 93.2% and 94.5%, respectively. Conclusion: We utilized the linear model to set the proper beam gating for predicting DLT within 5.0 mm to treat patients. We will investigate a proper process on x-ray fluoroscopy images to establish a reliable model predicting DLT for DM observed in x-ray fluoroscopy in the following two years.

目的 比较使用腹板俯卧位固定方式和使用体板、真空垫、体部定位膜三者相结合的个性化俯卧位固定方式在胰腺癌碳离子放疗中的摆位误差,为胰腺癌俯卧位放疗提供参考.方法 随机选取采用碳离子放疗的胰腺癌患者80例,其中采用腹板进行俯卧位固定的患者40例(腹板组),采用体板、真空垫、体部定位膜三者相结合进行俯卧位固定的患者40例(真空垫组).采用西门子kV级X线成像设备对每位患者采集正、侧位的正交野图像,与定位CT的DRR图像进行图像配准,获取六维方向(左右平移、头脚平移、前后平移、等中心旋转、俯仰旋转、横滚旋转)的摆位误差数据,并比较两组患者在六维方向的摆位误差.结果 真空垫组在左右平移、头脚平移、等中心旋转、俯仰旋转以及横滚旋转这5个方向上的摆位误差均明显小于腹板组,但在前后平移方向上的摆位误差大于腹板组,差异有统计学意义(P<0.05).结论 在胰腺癌患者的碳离子放疗中,采用体板、真空垫、体部定位膜三者相结合的个性化俯卧位固定方式的摆位误差整体上优于采用腹板的俯卧位固定方式,在放疗前摆位时可以在扣好体部定位膜后不再移动患者前后方向,以减小前后平移方向上的误差,研究结果可为今后胰腺癌俯卧位的放疗提供参考依据.

To evaluate the dosimetric uncertainties of symmetric Gaussian modelled in-air spot size/shape in our Syngo treatment planning system, we performed measurements of rDOF and TP width at a shadow depth of 2.7 mm. They are related to the effects of low dose halo and asymmetric spot shape. Empirically, a two-component Gaussian analytical model predicted the trend of rDOF and TP as a function of field size. From the result, the in-air spot size was described by a single Gaussian function for carbon-ion and high energy proton. The weights and widths for the second component of double Gaussian increased significantly as the beam energy decreases for protons. The TP fitting agreed with the rDOF fit for the scanned field (SF) of larger than 78 mm. For proton, the TP for SF of 12.0 mm for energies of 153.36 MeV/u and197.23 MeV/u, SF of 60.0 mm for energy of 48.08 MeV/u were fit better by single Gaussian component. The width of TP showed no field size dependence for each energy. Obtained Gaussian width by fitting TP was smaller than by fitting rDOF for carbon-ion. The empirical model allowed us to investigate the effects of beam emittance and scattering. They could provide reference values for clinical use and quality assurance.

Background We aimed at determining the safety and feasibility of spot-scanning carbon ion radiotherapy (CIRT) for patients with localized prostate cancer. Methods We enrolled 118 patients with localized prostate cancer who underwent treatment with spot-scanning CIRT at the Shanghai Proton and Heavy Ion Center (SPHIC) from January 2016 to December 2020. The dose was gradually increased from relative biological effectiveness (RBE)-weighted dose (DRBE) = 59.2–65.6 Gy in 16 fractions. The primary endpoint was the occurrence of acute and late toxicities, while the secondary endpoints were biochemical relapse-free survival (bRFS), distant metastasis-free survival (DMFS), prostate cancer-specific survival (PCSS), and overall survival (OS). Results The median follow-up time was 30.2 months (4.8–62.7 months). Acute grade 1 and 2 genitourinary (GU) toxicities were 15.3% and 18.6%, while acute grade 1 and 2 gastrointestinal (GI) toxicities were 2.5% and 0%, respectively. Late grade 1 and 2 GU toxicities were 4.2% and 1.7%, respectively. No late GI toxicity was observed. Moreover, there were no cases of severe acute or late toxicity (≥ grade 3). No significant association were observed between the factors and the acute GU toxicities, except for clinical target volume (CTV) (p = 0.031) on multivariate analysis. The 2-year bRFS, DMFS, PCSS, and OS were 100%, 100%, 100%, and 98.8%, respectively. Conclusion The 2-year outcomes were encouraging, providing additional and useful information on the feasibility and safety of spot-scanning CIRT for treating prostate cancer. Thus, we recommend long-term follow-up and prospective multicentered studies to reinforce the role of CIRT in the management of localized prostate cancer.

Purpose: The purpose of this study was to prospectively analyze the safety and feasibility of spot scanning carbon ion radiotherapy (CIRT) for patients with localized prostate cancer. Methods: 118 localized prostate cancer patients treated with spot scanning CIRT at Shanghai Proton and Heavy Ion Center (SPHIC) were enrolled in this dose escalated study. The dose was gradually increased from 59.2GyE to 65.6GyE in 16 fractions. The primary endpoint was the acute and late toxicities. Secondary endpoints were biochemical relapse free survival (bRFS), distant metastasis free survival (DMFS), prostate cancer-specific survival (PCSS), and overall survival (OS). Results: The median follow-up time was 30.2 months (4.8-62.7 months). Acute grade 1 and 2 genitourinary (GU) toxicities were 15.3% and 18.6%, while acute grade 1 and 2 gastrointestinal (GI) toxicities were 2.5% and 0%, respectively. Late grade 1 and 2 GU toxicities were 4.2% and 1.7%, respectively. No late GI toxicity were observed. There were no cases of severe acute or late toxicity (≥grade 3). The significant association was not found between the factors and the acute GU toxicities except for CTV volume (p=0.031) on multivariate analysis. The 2-year bRFS, DMFS, PCSS, OS were 100%, 100%, 100% and 98.8%, respectively. Conclusion: The 2 years’ outcomes are encouraging, providing additional and useful information on the feasibility and safety of spot scanning CIRT for prostate cancer. Long term follow-up and prospective multi-institutional data are warranted to reinforce the role of CIRT in the management of localized prostate cancer. Trial registration: Clinicaltrial, NCT02739659. Registered 15 April 2016

To ensure quality assurance (QA) of scanning proton and carbon-ion therapy doses, an efficient and reliable method to measure the energy dependency of the dose response function (DRF) of an optical scintillator detection system (OSDS), is required. We present a calibration process that corrects the non-linear sensitivity of the imager's electronic readings into linear light intensities. After calibration, a digital readout of green colored stimulated-light emission (SLE) are converted to nominal SLE (N_SLE). The slope of N_SLE as a linear function of dose is labelled as K-factor. The K-factors for 7 energies of carbon-ion and proton have been measured. For the highest (424.89 MeV/u) and lowest (97.87 MeV/u) energies of carbon-ion, the K-factors are 0.96 and 0.76 N_SLE/Gy. For the highest (218.56 MeV) and lowest (53.04 MeV) energies of protons, the K-factors are 0.96 and 0.86 N_SLE/Gy. The variation of K-factor for its energy dependence are 18% and 11% between lowest and highest energies of carbon-ion and proton beam respectively. Similar trending of the K-factor was seen for the red and blue colors with respect to the green color channel, although the signal magnitude was lower for the red channel. The OSDS dose response is weakly dependent on the energy of the carbon-ion and proton beams regardless of color channel. The energy-dependency of DRF and interactive capability of OSDS can be used to create efficient dosimetry tools to measure data for spot-scanning carbon-ion and proton radiotherapy.

目的 分析Siemens IONTRIS质子重离子治疗设备临床应用中各部位患者的摆位误差,以指导影像引导环节中采取更好的配准策略与方法.方法 选择45例接受Siemens IONTRIS质子重离子治疗的不同部位的患者.运用kV级正交X线成像设备进行影像引导,分别记录每位患者的手动配准和自动配准摆位误差.结果 头部仅有左右方向,头颈部有前后、等中心和横滚3个方向,胸部有左右、头脚、前后和等中心4个方向,腹部有头脚和横滚2个方向的自动配准摆位误差与手动配准摆位误差,差异有统计学意义(P<0.05).结论 Siemens IONTRIS质子重离子治疗设备的自动配准软件的配准准确度应用在不同部位存在较大差别,应当根据不同肿瘤部位选择适当的配准策略,推荐在头部肿瘤的配准时优先使用自动配准然后手动微调,可达到既快速又准确的目的.

PURPOSE:To estimate the Lyman Kutcher Burman (LKB) and multivariate NTCP models predicting the AUT of prostate cancer treated with CIRT. MATERIALS AND METHODS:A cohort of 154 prostate adenocarcinoma patients were retrospectively analyzed. The AUT levels were graded according to CTCAE 4.03. Based on dosimetric parameters and/or clinical factors, a set of variables with best-fit values determined in the two models was validated by the area under the receiver operating characteristic curve (AUC) and used to correlate the predicted and observed NTCP rates for both levels and related endpoints. RESULT:59 (38.3%) patients experienced AUT. For LKB model, the equivalent uniform doses (EUDs) were calculated to be 62.0 GyE (following V61.5 > 1.7%) and 61.2 GyE (following maximum dose > 63.0 GyE) with predicted NTCP rates of 37.0% (AUC: 0.71) and 15.6% (AUC: 0.65) for AUT G1&2 and G2 of bladder. While for the multivariate model, the predicted NTCP rates was 37.1% (AUC: 0.70) and 20.2% (AUC: 0.64) for AUT G1&2 and G2, associated with V61 and V65, respectively. Nocturia was associated with bladder volume and maximum dose for G1&2, with patient's age and maximum bladder dose for G2. Other predictable endpoints were associated with V≥61. The predicted NTCPs agree with the observed complication rates for bladder and its wall. CONCLUSIONS:The LKB model successfully predicted the NTCP rates of both AUT levels and urgency urination. The multivariate model predicted well on both levels and nocturia. Decreasing high bladder dose volume may reduce the incidence of AUT.

Objective To compare the application values and setup errors between vacuum bag plus body mask and customized alpha cradle duringproton and carbon therapy using Siemens 6D robotic couch in prostate cancer patients.Methods Nineteen patients received vacuum bag plus body mask setup were allocated into the vacuum bag group andl9 patients with alpha cradle were assigned into the alpha cradle group.Orthogonal X-ray portals were performed to verify the treatment position before beam delivery in every fraction.The couch correction between the portal and reference DRR through manual image registration was recorded as setup errors in 6 directions including the lateral,supine-inferior,anterior-posterior,yaws,roll and pitch,respectively.Two-tail t-test was used to analyze the setup error data from each direction between two groups.Results In total,452 and 436 sets of data errors were collected from the vacuum bag and alpha cradle groups.The average setup errors and standard deviation in the vacuum bag and alpha cradle groups in the lateral,supine-inferior,anterior-posterior,yaws,roll and pitch directions were (0.63±0.48) cm vs.(0.33±0.24) cm (P=0.000),(0.40±0.3) cm vs.(0.31±0.25) cm (P=0.000),(0.69±0.61) cm vs.(0.82±0.69) cm (P=0.006),0.65°±0.47°vs 0.32°±0.25°(P=0.000),1.05°±0.95°vs 1.16°±0.94° (P=0.100) and 0.67°±0.56°vs 0.40°±0.36° (P=0.000),respectively.The maximum setup errors were detected in the pitch direction for both groups.Conclusions During the proton and carbon therapy using Siemens 6D robotic couch,two setup methods using vacuum bag plus body mask and customized alpha cradle should be selected according to the individual conditions of patients.A customized foot fixer should be utilized to reduce the uncertainty in the femoral head region.