In-room PET Monitoring of Proton Therapy

描述(申请人提供)：质子疗法是治疗形状不规则和接近临界器官的肿瘤的一种有利的治疗方法，因为它能够将高度适形的辐射剂量分布传递到肿瘤靶区，并更好地保留周围正常组织。对患者体内射束传输的验证对于确保治疗计划和传输系统的正常运行非常重要。人们正在研究正电子发射断层扫描(PET)，通过成像患者体内产生的发射正电子的放射性核素的活度分布来验证束流传递。质子治疗的PET监测可以在照射期间(在束内)或在照射后(离线)进行。束内监测是有利的，因为短寿命核素(如15O)和相对长寿命核素(如11C和13N)都可以以高灵敏度成像。然而，它需要将专用的PET成像系统集成到质子治疗设备中，通常是双头系统，因为由于几何限制，全环几何形状是不可行的，也不会产生完整的断层扫描数据。技术要求较低的离线方法包括将患者在照射后转移到附近的商业PET扫描仪(通常是全环系统)治疗室外进行成像。然而，通常在辐射和PET成像之间存在延迟，因此短暂的核素，最重要的是15O，将已经衰变。作为这两种情况的组合，治疗室内的全环PET扫描仪是非常可取的，以便在照射后立即对患者进行成像。随着MGH最近推出可移动的全环PET扫描仪，质子治疗的室内PET监测成为可能。这笔赠款的目的是在一项试点临床研究中，通过成像质子治疗期间患者体内产生的发射正电子的放射性核素的内源活度分布，确定使用移动PET扫描仪对质子治疗进行室内自适应监测的可行性和潜力。 公共卫生相关性：质子治疗是治疗形状不规则和接近关键器官的肿瘤的一种有利的治疗方式，因为它能够将高度适形的辐射剂量分布传递到肿瘤靶区，并更好地保留周围正常组织。对患者体内射束传输的验证对于确保治疗计划和传输系统的正常运行非常重要。人们正在研究正电子发射断层扫描(PET)，通过成像患者体内产生的发射正电子的放射性核素的活度分布来验证束流传递。目前，质子治疗的正电子发射计算机断层扫描(PET)监测是在照射期间(束内)或照射后(离线，延迟)进行的。我们将在一项试点临床研究中，确定在一项试点临床试验中，质子治疗的室内PET监测/验证(立即脱离束流，不延迟)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.