Real-time verification of proton dose delivery

质子剂量输送的实时验证

• 批准号: 7981827
• 负责人: Jerimy C. Polf
• 金额: $ 20.62万
• 依托单位: UNIVERSITY OF TX MD ANDERSON CAN CTR
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-01 至 2012-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7981827
• 关键词: Adverse effects; Anatomy; Area; Award; Binding; Biological; Calibration; Cancer Patient; Cancerous; Categories; Cell Nucleus; Characteristics; Clinical; Data; Deposition; Detection; Development; Dose; Effectiveness; Electronics; Electrons; Elements; Ensure; Evaluation; External Beam Radiation Therapy; Family suidae; Fatty acid glycerol esters; Feedback; Gamma Rays; Goals; Grant; Histocompatibility Testing; Hypoxia; Image; Incidence; Individual; Kidney; Knowledge; Lead; Left; Legal patent; Liver; Lung; Maps; Measurement; Measures; Methods; Modeling; Monitor; Muscle; Nature; Noise; Normal tissue morphology; Nuclear; Oncologist; Optics; Outcome; Oxygen; Paper; Patients; Physics; Procedures; Process; Protons; Publishing; Quality of life; Radiation; Radiation therapy; Reaction Time; Research; Resolution; Sheep; Spectrum Analysis; Staging; Study models; System; Techniques; Time; Tissue Sample; Tissues; Uncertainty; Width; Work; X-Ray Computed Tomography; analog; animal tissue; base; bone; clinical application; density; detector; human tissue; image reconstruction; imaging modality; improved; in vivo; innovation; irradiation; novel; proton beam; public health relevance; response; treatment planning; tumor

DESCRIPTION (provided by applicant): During proton therapy treatment, protons interact with both the nucleus and bound electrons of atoms within patient tissue. Proton-nucleus interactions can leave behind an intact atomic nucleus in an excited energy state that quickly decays, frequently through emission of a characteristic gamma-ray, a phenomenon known as "prompt emission". This gamma emission occurs only where proton-nucleus interactions (and thus dose deposition) occur and the energy spectrum of the emission is dependent on the specific atomic composition of the irradiated tissue. We hypothesize that by properly measuring the prompt gamma-ray emission that occurs during proton dose delivery, the dose delivery and the composition of tissue irradiated can be verified. The long term goal of this research is to develop a clinically viable Prompt Gamma Imaging (PGI) system capable of measuring both the composition and density of tissues irradiated within the patient. The specific aims of this proposal are (1) to determine the response of gamma-ray detectors within a proton treatment vault and (2) to determine the inherent resolution of image reconstruction for the proposed PGI method. To achieve the stated aims, both measurements and Monte Carlo calculations will be made to determine the shielding levels and detector timing response required to isolate and measure prompt emission during proton beam delivery. Calculations of the prompt emission detection process from a Monte Carlo model will be used to determine the effects of the finite energy and spatial resolution of the gamma-ray detectors on the resolution of images reconstructed with the proposed PGI method. Based on the results of these studies, we will determine the overall feasibility of measuring the prompt gamma-ray spectra emitted during proton beam radiotherapy and for reconstructing images of the composition and density of tissues irradiated with the proposed PGI method. The significance of a method to image and track changes to the elemental composition and densities of tissues irradiated during proton therapy is multi-fold. First, such a method could allow for the direct measurement of changes to the stopping powers for irradiated tissues over the course of treatment. The stopping power values obtained from measurements would allow for more accurate calculation of proton beam range and dose delivery within the patient over the course of treatment, thus improving accuracy of the proton treatment delivery. Second, PGI would provide a direct method to evaluate changes in irradiated tissues, such as tumor hypoxia or the elemental composition of healthy tissues over the treatment course that could be correlated to tumor response and/or the onset of normal tissue complications. PUBLIC HEALTH RELEVANCE: The proposed research aims to develop novel methods to measure and image the atomic composition of tissues irradiated during proton radiotherapy in-vivo, allowing us to study biological changes and response of these tissues. This would provide a means to measure and track changes to elemental composition in these tissues on a daily basis over the course of treatment. Such capabilities would allow for the monitoring of a patient's response to proton radiotherapy (via measured changes to tissue composition), thus providing a means for the oncologists to change and adapt treatment delivery for each patient individually based on their measured response.

描述（由申请人提供）：在质子疗法治疗期间，质子与患者组织内原子核和束缚电子相互作用。质子-核相互作用可以留下处于激发能态的完整原子核，该原子核通常通过发射特征伽马射线而快速衰变，这种现象称为“瞬发发射”。这种伽马发射仅在发生质子-核相互作用（以及因此剂量沉积）的情况下发生，并且发射的能谱取决于受照射组织的特定原子组成。我们假设，通过正确测量质子剂量输送过程中发生的即时伽马射线发射，可以验证剂量输送和受照射组织的成分。这项研究的长期目标是开发一种临床上可行的瞬发伽马成像（PGI）系统，能够测量患者体内受照射组织的成分和密度。该提案的具体目标是 (1) 确定质子治疗库内伽马射线探测器的响应，以及 (2) 确定所提出的 PGI 方法的图像重建的固有分辨率。为了实现既定目标，将进行测量和蒙特卡罗计算，以确定在质子束传输期间隔离和测量即时发射所需的屏蔽水平和探测器定时响应。蒙特卡罗模型的即时发射检测过程的计算将用于确定伽马射线探测器的有限能量和空间分辨率对使用所提出的 PGI 方法重建的图像分辨率的影响。根据这些研究的结果，我们将确定测量质子束放射治疗期间发出的瞬发伽马射线光谱以及重建用所提出的 PGI 方法照射的组织的成分和密度图像的总体可行性。在质子治疗期间对受照射组织的元素组成和密度变化进行成像和跟踪的方法具有多重意义。首先，这种方法可以直接测量治疗过程中受照射组织的阻止能力的变化。从测量中获得的阻止功率值将允许更准确地计算质子束射程和治疗过程中患者体内的剂量输送，从而提高质子治疗输送的准确性。其次，PGI 将提供一种直接方法来评估受辐射组织的变化，例如治疗过程中肿瘤缺氧或健康组织的元素组成，这些变化可能与肿瘤反应和/或正常组织并发症的发生相关。 公共健康相关性：拟议的研究旨在开发新方法来测量和成像体内质子放射治疗期间受照射组织的原子成分，使我们能够研究这些组织的生物变化和反应。这将提供一种在治疗过程中每天测量和跟踪这些组织中元素成分变化的方法。这种功能将允许监测患者对质子放射治疗的反应（通过测量组织成分的变化），从而为肿瘤学家提供一种根据测量的反应单独改变和调整每个患者的治疗方案的方法。