Dosimetric properties of a novel brachytherapy balloon applicator for the treatment of malignant brain-tumor resection-cavity margins
Dosimetric properties of a novel brachytherapy balloon applicator for the treatment of malignant brain-tumor resection-cavity margins
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DOI：
10.1016/s0360-3016(98)00215-6
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发表时间：
1998-09-01
影响因子：
7
通讯作者：
Williamson, JF
中科院分区：
文献类型：
--
作者：
Dempsey, JF;Williams, JA;Williamson, JF
目的：本文描述了一种新型的球囊近距离放射治疗施源器的剂量学特性的治疗周围的组织切除腔的恶性脑tumor.Methods和Materials：该施源器包括一个可膨胀的硅胶球囊水库连接到一个可定位的导管，术中植入到切除腔和术后充满了液体放射性核素溶液。一个简单的剂量学模型，在均匀介质中有效，并从Monte Carlo光子输运模拟的结果的基础上，被用来确定充满光子发射放射性核素溶液的球形几何形状的气球的剂量学特性，分数深度剂量（FDD）的配置文件，沿着与活动密度，和总活动需要达到指定的剂量率作为光子能量和源容器的几何形状的函数进行了研究。计算剂量体积直方图（DVH），比较理想的气球喷头治疗，以传统的I-125种子体积implants.Results：对于可实现的活动密度和总活动，经典的低剂量率（LDR）治疗残留疾病的距离可达1厘米，从;切除腔壁的剂量穿透率可以用半径在0.5cm和2.5cm之间的球囊施加器来实现。这些施加器的剂量穿透率随着球囊半径近似线性地增加。通过将放射性核素的选择与源几何形状操纵相结合，可以使FDD轮廓显著地或多或少地穿透。与I-125粒子植入DVH的比较表明，该施源器可以提供更适形的治疗，没有靶组织剂量不足，靶组织剂量过量较少，没有健康组织“热点”;然而，更多健康组织体积接受处方剂量或更少的剂量。该装置，当填充有I-125溶液时，适用于经典的LDR治疗，并且在几个方面可能优于I-125放射性种子植入物。操纵该装置的剂量测定特性可以改善其用于脑肿瘤治疗的特性，并且可以使其适合于在保守性乳腺癌治疗中提高乳房肿瘤切除术边缘。(C)1998年爱思唯尔科学公司
Purpose: This paper characterizes the dosimetric properties of a novel balloon brachytherapy applicator for the treatment of the tissue surrounding the resection cavity of a malignant brain tumor.Methods and Materials: The applicator consists of an inflatable silicone balloon reservoir attached to a positionable catheter that is intraoperatively implanted into the resection cavity and postoperatively filled with a liquid radionuclide solution. A simple dosimetric model, valid in homogeneous media and based on results from Monte Carlo photon-transport simulations, was used to determine the dosimetric characteristics of spherical geometry balloons filled with photon-emitting radionuclide solutions, Fractional depth-dose (FDD) profiles, along with activity densities, and total activities needed to achieve specified dose rates were studied as a function of photon energy and source-containment geometry. Dose-volume histograms (DVHs) were calculated to compare idealized balloon-applicator treatments to conventional I-125 Seed volume implants.Results: For achievable activity densities and total activities, classical low dose rate (LDR) treatments of residual disease at distances of up to 1 cm from the; resection cavity wall are possible with balloon applicators having radii between 0.5 cm and 2.5 cm, The dose penetration of these applicators increases approximately linearly with balloon radius. The FDD profile can be made significantly more or less penetrating by combining selection of radionuclide with source-geometry manipulation. Comparisons with I-125 seed-implant DVHs show that the applicator can provide a more conformal therapy with no target tissue underdosing, less target tissue overdosing, and no healthy tissue "hot spots;" however, more healthy tissue volume receives a dose of the prescribed dosage or less.Conclusions: This device, when filled with I-125 solution, is suitable for classical LDR treatments and may be preferable to I-125 interstitial-seed implants in several respects. Manipulation of the dosimetric properties of the device can improve its characteristics for brain tumor treatment and may make it suitable for boosting the lumpectomy margins in conservative breast cancer treatment. (C) 1998 Elsevier Science Inc.