Prostate Edema in Permanent Interstitial Brachytherapy

永久性间质近距离放射治疗中的前列腺水肿

• 批准号: 7683899
• 负责人: Zhe Chen
• 金额: $ 27万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-01 至 2011-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7683899
• 关键词: 3-Dimensional; Adopted; Algorithms; Anisotropy; Brachytherapy; Cancer Patient; Cell Cycle; Cesium; Classification; Clinical; Clinical Management; Complex; Computational algorithm; Data Set; Development; Disease; Dose; Dose-Rate; Early treatment; Edema; Effectiveness; Ensure; Evaluation; Evolution; Financial compensation; Gland; Goals; Half-Life; Hand; I125 isotope; Image; Image Analysis; Implant; Implantation procedure; Individual; Intervention; Lead; Magnetic Resonance Imaging; Malignant neoplasm of prostate; Measures; Methods; Modality; Modeling; Modification; Motion; Needles; Normal tissue morphology; Operative Surgical Procedures; Organ; Palladium 103; Patients; Pattern; Photons; Positioning Attribute; Process; Property; Prostate; Quality of Care; Radiation; Radiation Tolerance; Radiation therapy; Radioactive; Radioactive Seed Implantation; Radioactivity; Radiobiology; Radioisotopes; Radiometry; Recording of previous events; Relative (related person); Research; Resolution; Sampling; Source; Spatial Design; Staging; Swelling; Techniques; Therapeutic; Therapeutic Intervention; Time; Tissues; Trauma; Treatment Efficacy; Treatment outcome; Ultrasonography; Uncertainty; United States; Validation; Variant; base; cancer cell; clinical application; clinical practice; clinically significant; design; dosimetry; implantation; improved; interest; interstitial; irradiation; migration; public health relevance; success; treatment planning; tumor

DESCRIPTION (provided by applicant): Permanent interstitial brachytherapy (PIB) for early stage organ-confined prostate cancer involves permanent surgical implantation of about 100 radioactive sources into the prostate so that a therapeutic radiation dose can be delivered to the cancer cells while minimizing the doses to the surrounding normal tissues. Potential advantages of this approach include continuous irradiation of cancer cells which reduces the impact of cell- cycle dependent variations in cellular radiosensitivity; reduced dose to normal tissues, which allows escalation of tumor dose for increased tumor control; use of a one-time implant procedure, which is more convenient for patients than the fractionated daily treatments of external beam radiotherapy (EBRT) that often last more than six weeks; and the avoidance of potentially detrimental geometric misses caused by the uncertainties in daily patient setup and by inter- and intra-fractional organ motions in EBRT. To fully achieve the potential of PIB, one must be able to accurately place these sources in a pre-designed spatial pattern for producing adequate tumor coverage and must maintain the initial source positions during the protracted PIB dose delivery, in addition to having an accurate characterization of the dosimetric properties of each source. In prostate PIB, however, variation in post-implant source position is inevitable because edema induced by the surgical procedure causes the prostate gland to swell rapidly (to as large as twice of its pre-surgery volume) followed by a gradual resolution that can require more than a month. A number of recent studies have shown that edema-induced variations in prostate volume and source positions can lead to large variations in the dose delivered to the tumor, which, if ignored, can have detrimental consequences for patients developing moderate or severe edema. This has become an especially urgent issue with the recent introduction and clinical application of a new 131Cs source, which has a shorter radioactivity decay half-life (9.7 day) than radionuclides used previously and therefore is more sensitive to the edema-induced source position variations. The specific aims of this project are: 1) to develop a new and integrated approach for accurate determination of the dosimetric effects of edema so that effective therapeutic intervention strategies can be designed and integrated into the planning and treatment of PIB with or without radiobiology guidance; 2) to conduct a systematic validation of the proposed approach and the existing edema models using the histories of edema evolution measured for 15 PIB patients; and 3) to perform a comprehensive evaluation of the clinical significance of edema-induced dosimetric variations and the effectiveness of therapeutic intervention strategies so that the efficacy of PIB can be optimized for each individual patient. We hypothesize that the successful completion of this project will enable effective clinical management of the effects of prostate edema for each patient and thereby help to achieve the full potential of PIB in the treatment of early-stage prostate cancer. Public Health Relevance: Permanent implantation of radioactive seeds containing iodine-125, palladium-103, or cesium-131 in the prostate, also called brachytherapy, has become a popular form of radiation therapy for carefully selected prostate cancer patients. The clinical success of brachytherapy is highly dependent on the ability to properly plan the procedure, implant the radioactive source, and perform dosimetry in a way that ensures that the radiation dose distributions are well defined and appropriate for optimal treatment of the tumor. This ability, however, has been hampered by the inevitable development and resolution of surgery-induced prostate edema, which can last over a month. The primary objective of this project is to develop a new method to consider the effects of edema in radiation dosimetry and treatment planning so that the efficacy of this therapy can be optimized for each patient.

描述（由申请人提供）：用于早期器官局限性前列腺癌的永久性间质性近距离放射治疗（PIB）涉及将约100个放射源永久性手术植入前列腺，以便可以将治疗辐射剂量输送到癌细胞，同时最大限度地减少对周围正常组织的剂量。这种方法的潜在优点包括癌细胞的连续照射，其减少了细胞周期依赖性变化对细胞放射敏感性的影响;减少了对正常组织的剂量，其允许肿瘤剂量的增加以增加肿瘤控制;使用一次性植入程序，这比通常持续六周以上的体外放射治疗（EBRT）的每日分次治疗更方便患者;以及避免由日常患者设置中的不确定性以及由EBRT中的分次间和分次内器官运动引起的潜在有害的几何错过。为了充分实现PIB的潜力，必须能够将这些源准确地放置在预先设计的空间图案中以产生足够的肿瘤覆盖，并且除了具有每个源的剂量测定特性的准确表征之外，还必须在延长的PIB剂量递送期间保持初始源位置。然而，在前列腺PIB中，植入后源位置的变化是不可避免的，因为外科手术引起的水肿导致前列腺迅速肿胀（达到其术前体积的两倍），然后逐渐消退，可能需要一个多月。最近的一些研究表明，水肿引起的前列腺体积和源位置的变化可能导致递送到肿瘤的剂量的大的变化，如果忽略，可能对发展中度或重度水肿的患者产生有害的后果。这已成为一个特别紧迫的问题，最近推出和临床应用的一种新的131 Cs源，它具有较短的放射性衰变半衰期（9.7天）比以前使用的放射性核素，因此是更敏感的水肿引起的源位置的变化。本项目的具体目标是：1）开发一种新的和综合的方法，用于准确确定水肿的剂量学效应，以便在有或没有放射生物学指导的情况下，设计有效的治疗干预策略并将其整合到PIB的计划和治疗中;（二）使用15 PIB测量的水肿演变历史对所提出的方法和现有水肿模型进行系统验证病人; 3）对水肿引起的剂量学变化的临床意义和治疗干预策略的有效性进行综合评价，以便针对每个患者优化PIB的疗效。我们假设，该项目的成功完成将使每例患者的前列腺水肿效应得到有效的临床管理，从而有助于充分发挥PIB治疗早期前列腺癌的潜力。公共卫生相关性：在前列腺中永久植入含有碘-125、钯-103或铯-131的放射性粒子，也称为近距离放射治疗，已成为仔细选择的前列腺癌患者的流行放射治疗形式。近距离放射治疗的临床成功在很大程度上取决于正确计划手术、植入放射源和进行剂量测定的能力，以确保辐射剂量分布明确且适合肿瘤的最佳治疗。然而，这种能力受到手术引起的前列腺水肿的不可避免的发展和解决的阻碍，这种水肿可能持续一个多月。该项目的主要目标是开发一种新的方法来考虑辐射剂量测定和治疗计划中水肿的影响，以便可以针对每个患者优化这种治疗的疗效。