Gamma Ray Spectroscopy for Dose Rate Constants

伽马射线能谱测定剂量率常数

基本信息

批准号：
7000310
负责人：
RAVINDER NATH
金额：
$ 21.55万
依托单位：
YALE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2004
资助国家：
美国
起止时间：
2004-01-14 至 2007-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7000310
关键词：
electronic spectra emission spectrometry gamma radiation iodine method development neoplasm /cancer radionuclide therapy palladium prostate neoplasms radiation dosage

项目摘要

DESCRIPTION (provided by applicant): Permanent implantation of either iodine-125 seeds or palladium-103 radioactive seeds in the prostate has become a popular form of radiation therapy for carefully selected prostate cancer patients. The procedure is minimally invasive and is usually performed in a one-day surgery unit on an outpatient basis. The treatment related morbidity such as urinary incontinence and sexual impotence is fairly low for seed implantation, and control of the cancer in selected patients is as good as that with other treatment modalities such as surgery. For these reasons the public interest in seed implantation is growing rapidly. The clinical success of radiation therapy has been highly dependent on the capability of delivering a desired prescription dose. For prostate seed implant, such a capability is impinged on both the accuracy of placing the radioactive seeds in a predesigned spatial pattern for adequate spatial dose coverage and on the accuracy of the fundamental dosimetry properties of each individual seed. The primary objective of this project is to develop a new method for determination of dose rate constant, the only absolute quantity in the AAPM TG-43 formalism, for interstitial brachytherapy seeds that are used for prostate seed implants. The new method utilizes high-resolution gamma ray spectrometry and would be capable of determining the dose rate constant without the need of knowing the air kerma strength. Our hypothesis is that the proposed new method based on gamma ray spectrometry is superior to currently accepted standard experimental method using LiF TLDs. It has the potential of improving the accuracy and consistency of the dosimetry of prostate seed implants. This improvement in absolute dosimetry will impact the clinical practice of all brachytherapy patients because unlike random errors, errors in absolute dosimetry parameters for different models of brachytherapy sources affect all patients in a systematic fashion and in the same direction. Since prostate brachytherapy has now become a treatment method of choice for selected patients and this popularity has led to the introduction of many new designs of seeds for clinical implementation, we hypothesize that gamma ray spectroscopy can be used to reduce the uncertainty in dose rate constants and improve the dosimetry in a large number of prostate cancer patients.

描述（由申请人提供）：前列腺中的碘-125种子或钯103放射性种子的永久性植入已成为精心选择的前列腺癌患者的放射治疗的一种流行形式。该手术是最小的侵入性，通常在门诊的一日手术单元中进行。与治疗相关的发病率（例如尿失禁和性阳性）对于种子植入而言相当低，并且所选患者对癌症的控制与其他治疗方式（例如手术）一样好。由于这些原因，公众对种子植入的兴趣正在迅速增长。放射治疗的临床成功高度取决于提供所需处方剂量的能力。对于前列腺种子植入物，这种能力都构成了将放射性种子放置在预先设计的空间模式中的准确性上，以实现足够的空间剂量覆盖范围以及每个种子的基本剂量测定特性的准确性。该项目的主要目的是开发一种确定剂量速率常数的新方法，这是AAPM TG-43形式主义中唯一的绝对数量，用于用于前列腺种子植入物的间质近距离近距离种子。新方法利用了高分辨率伽马射线光谱法，并且能够确定剂量速率常数，而无需知道空气kerma强度。我们的假设是，基于伽马射线光谱的提出的新方法优于使用LIF TLDS的当前接受的标准实验方法。它具有提高前列腺种子植入物剂量法的准确性和一致性的潜力。绝对剂量测定法的这种改善将影响所有近距离放射治疗患者的临床实践，因为与随机误差不同，不同模型的近距离放射治疗来源的绝对剂量测定参数的错误会以系统的方式和相同的方向影响所有患者。由于前列腺近距离放射治疗现已成为某些患者的首选方法，并且这种受欢迎程度导致了许多新的种子设计以进行临床实施，因此我们假设可以使用γ射线光谱法来减少大量剂量率常数的不确定性并改善大量的Prostate癌症患者的dosimetry。