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.

目的 探讨主动呼吸控制(Active Breathing Coordinator,ABC)和呼吸门控技术(Respiratory Gating,RG)在肺癌粒子治疗中的稳定性.方法 选择采用两种技术的肺癌病例共计40例为研究对象,其中使用ABC技术20例,使用RG技术20例.使用ABC技术的病例选择在深吸气屏住状态下扫描重建的CT图像,与相同状态下定位CT图像进行肿瘤位移值的比较;使用RG技术的病例选择在呼气末20%至吸气初20%的时相重建的平均CT图像,与呼气末20%至吸气初20%的时相重建的定位CT图像进行肿瘤位移值比较,并对数据进行t检验.结果 采用ABC与RG技术可见肿瘤位移头脚方向的绝对值误差均值为(0.10±0.04)cm vs.(0.34±0.17)cm,P<0.001;离散度为(0.08±0.03)cm vs.(0.23±0.15)cm(P<0.001);计划靶区的V95离散度为(1.95%±1.3%)vs.(0.61%±0.45%)(P=0.015).结论 在肺癌粒子治疗中,使用ABC的肿瘤位置头脚方向的稳定性优于RG技术,且在剂量学方面ABC更有优势.

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.

Objective:To study and analyze the uncertainty of active breathing coordinator (ABC) technology for liver and lung cancer therapy using proton and heavy ion.Methods:Before each treatment, each patient received a verification radiograph through the supporting imaging frame in treatment room. 200 verification radiographs were taken for 20 lung cancer patients and 200 for 20 liver cancer patients. Ipiodol markers, which were fixed relative to the location of the tumor, were injected into the liver cancer patients. The position changes of ipiodol markers could reflect the position changes of liver tumors. Verification radiographs were registered with the vertebral body as the main target, and the change value of tumor location was recorded.Results:For liver cancer cases, the values of position change in the left and right, head and foot, and dorsal abdomendirection were (-0.05± 0.28) cm, (0.15±0.33) cm, (-0.12±0.27) cm, and (-0.03±0.13) cm, (-0.05±0.14) cm and (0.02±0.16) cmfor lung cancer cases, respectively ( P=0.280, <0.001, <0.001). For liver cancer cases, the dispersionin the left and right, head and foot, and dorsal abdomendirectionwas (0.20±0.09) cm, (0.25±0.06) cm, (0.19±0.09) cm, and (0.09±0.03) cm, (0.10±0.03) cm and (0.13±0.03) cm for lung cancer cases, respectively ( P<0.001, <0.001, 0.008). The proportion of tumor location changes of≤5 mm in three directions in liver and lung cancer patientswas (92%, 83%, 93%) vs. (99%, 99%, 100%)( P=0.030, 0.002, 0.007). Conclusion:The application of ABC technology in the proton heavy ion therapy of lung and liver cancer has good reproducibility, and the stability of ABC technology in the treatment of lung cancer is better than that of liver cancer.

目的 主动呼吸控制技术(Active Breathing Coordinator,ABC)是一种通过主动控制呼吸来减小由呼吸引起的器官运动的有效方法,目前使用ABC在光子放疗有相关报道,但在粒子治疗,尚无相关报道.本研究对ABC用于肝癌粒子治疗时,肝脏碘油位置进行测量与分析.方法 入组本研究的肝癌患者共10位,10位均肝癌碘油沉积良好,并顺利完成治疗,期间共拍摄100次验证片.每次治疗之前,通过粒子治疗设备(Iontris,Siemens)配套的拍片架对患者相应的治疗位置拍摄验证片并与DRR图像进行配准.因患者体内均植入碘油且碘油与肝脏肿瘤位置相对固定,因而在本研究是以碘油间接代替肝脏肿瘤.在基于椎体配准好的情况下,再测量验证片中的碘油与DRR图像中的碘油的偏差值,记录数据并分析碘油在Lat(X方向直线移动)、Long(Y方向直线移动)、Vert(Z方向直线移动)三个方向上的偏差值.结果 10位患者均配合良好,在透视情况下观察吸气屏住均无漏气行为.10位患者的碘油位置在Lat、Long、Vert三个方向上的误差均值分别为(0.19±0.20)cm,(0.23±0.21)cm,(0.18±0.19)cm;Lat、Long、Vert的负数均值分别为(-0.17±0.14)cm,(-0.22±0.21)cm,(-0.19±0.16)cm;Lat、Long、Vert的正数均值分别为(0.22±0.24)cm,(0.25±0.21)cm,(0.19±0.22)cm.结论 通过对所得数据的分析以及相关研究的比较,可知应用ABC在粒子治疗中可以很好地控制呼吸运动对肝脏位置的影响,重复性好,不确定性小,符合我院临床治疗的标准;同时可以为医生外扩边界提供数据基础.

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.