In-room PET Monitoring of Proton Therapy

描述（由申请人提供）：质子治疗是一种用于不规则形状和靠近关键器官的肿瘤的有利治疗方式，因为其能够向肿瘤靶体积输送高度适形的辐射剂量分布，同时更好地保护周围正常组织。验证患者体内的射束输送对于确保治疗计划和输送系统的正常功能非常重要。正电子发射断层扫描（PET）正在研究通过对患者体内产生的正电子发射放射性核素的活动分布进行成像来验证射束输送。质子治疗的PET监测可以在照射期间（束内）或之后（离线）进行。束内监测是有利的，因为短寿命（例如15O）和相对长寿命的核素（例如11C和13N）都可以以高灵敏度成像。然而，它需要将专用PET成像系统集成到质子治疗设施中，通常是双头系统，因为由于几何约束，全环几何形状是不可行的，并且不会产生完整的断层摄影数据。技术要求较低的离线方法涉及将患者运送到治疗室外附近的商业PET扫描仪（通常是全环系统），以便在照射后进行成像。然而，通常在辐射和PET成像之间存在延迟，使得短寿命的核素，最重要的是15O，会衰变。作为这两种情况的组合，治疗室内的全环PET扫描仪是非常理想的，以便患者可以在照射后立即成像。质子治疗的室内PET监测是可能的，最近可用的移动的全环PET扫描仪在MGH。该补助金的目标是在试点临床研究中，通过对质子治疗期间患者体内产生的正电子发射放射性核素的内源性活度分布进行成像，确定使用移动的PET扫描仪进行质子治疗室内自适应监测的可行性和潜力。 公共卫生相关性：质子治疗是一种有利的治疗模式，用于不规则形状和关键器官附近的肿瘤，因为它能够提供高度适形的辐射剂量分布到肿瘤靶体积，更好地保护周围的正常组织。验证患者体内的射束输送对于确保治疗计划和输送系统的正常功能非常重要。正电子发射断层扫描（PET）正在研究通过对患者体内产生的正电子发射放射性核素的活动分布进行成像来验证射束输送。质子治疗的PET监测目前在照射期间（束内）或之后（离线，延迟）进行。我们将在一项试点临床研究中确定质子治疗的室内PET监测/验证（立即关闭射束，无延迟）在试点临床试验中的可行性和潜力。

DESCRIPTION (provided by applicant): Proton therapy is a favorable treatment modality for tumors with irregular shapes and near critical organs because of its ability to deliver highly conformal radiation dose distributions to the tumor target volume, with better sparing of surrounding normal tissues. Verification of the beam delivery within the patient is very important to ensure the proper functioning of treatment planning and delivery systems. Positron emission tomography (PET) is being investigated for the validation of beam delivery by imaging the activity distribution of positron-emitting radionuclides produced within the patient. The PET monitoring of proton therapy can be performed either during (in-beam) or after (off-line) the irradiation. In-beam monitoring is advantageous as both short-lived (such as 15O) and relatively long-lived nuclides (such as 11C and 13N) can be imaged with high sensitivity. However, it requires the integration of a dedicated PET imaging system into the proton therapy facility, usually a dual-head system since full-ring geometry is not feasible because of geometric constraints, and does not lead to full tomographical data. The technically less-demanding Off-line approach involves transporting the patient to a nearby commercial PET scanner (usually a full-ring system) outside the treatment room for imaging after the irradiation. However, usually there is a delay between irradiation and PET imaging so that short-lived nuclides, most importantly 15O, would have decayed. As a combination of these two scenarios, a full-ring PET scanner within the treatment room is very desirable so that the patient can be imaged immediately after irradiation. The in-room PET monitoring of proton therapy is possible with the recent availability of a mobile full-ring PET scanner at MGH. The goal of this grant is to establish, in a pilot clinic study, the feasibility and potentials of using a mobile PET scanner for in-room adaptive monitoring of proton therapy by imaging the endogenous activity distribution of positron-emitting radionuclides produced within the patient during proton therapy. PUBLIC HEALTH RELEVANCE: Proton therapy is a favorable treatment modality for tumors with irregular shapes and near critical organs because of its ability to deliver highly conformal radiation dose distributions to the tumor target volume, with better sparing of surrounding normal tissues. Verification of the beam delivery within the patient is very important to ensure the proper functioning of treatment planning and delivery systems. Positron emission tomography (PET) is being investigated for the validation of beam delivery by imaging the activity distribution of positron-emitting radionuclides produced within the patient. The PET monitoring of proton therapy is currently performed either during (in-beam) or after (off-line, with delay) the irradiation. We will establish, in a pilot clinic study, the feasibility and potentials of in-room PET monitoring/verification (immediately off-beam, no delay) for proton therapy in a pilot clinical trial.