Intracranial Conformal Avoidance Radiation Therapy

描述(由申请人提供)：本申请请求支持确定调强放疗(IMRT)治疗计划过程中的分数大小等效剂量(FED)水平，这些肿瘤仅限活检的低度恶性脑肿瘤，导致被动语言理解(听力)、语言、精细运动控制和视觉(视觉)等特定神经功能损伤较低，因此在光学引导适形回避放射治疗期间可以节省这些区域。我们假设，将功能磁共振成像(FMRI)与神经学评估结合使用，将导致更好地了解分数大小等效剂量(FED)水平(最大FED或平均FED)，这些FED是从导致特定神经功能损害的功能特定剂量体积直方图获得的。使用FED形式主义，人们可以将床面值重新转换为以某些标准剂量/分数提供的生物等效剂量，产生的数字与使用典型的外部束流计划提供的剂量水平更直接地进行比较。然后，可以将导致特定神经功能最小损害的允许FED水平用于图像引导适形避免放射治疗计划的设计。 这项拟议的研究基于大量的初步数据，这些数据表明，功能磁共振成像增加了有关负责特定神经功能(被动语言理解(听力)、语言、精细运动控制和视觉)的大脑有说服力的体积的位置的额外信息，这些功能可以被纳入放射治疗计划，目的是减少对这些区域的辐射损伤。该项目的具体目标是： 1)根据不同阈值的激活图，对良性脑肿瘤和仅活检的低度恶性脑肿瘤患者的脑功能区功能图的重复性进行评估和量化。2)应用神经认知评估工具对影像引导下颅脑放射治疗的神经功能损伤进行评估，并得出特定神经功能损伤与相应脑功能区所接受FED的剂量反应曲线。

DESCRIPTION (provided by applicant): This application requests support to determine the Fraction Size Equivalent Dose (FED) levels for the intensity modulated radiotherapy (IMRT) treatment planning process of benign and biopsy only low grade brain neoplasms that lead to a low impairment in the specific neurological functions of passive language comprehension (hearing), language, fine motor control, and visual perception (vision), and therefore allow for sparing of these areas during optical guided conformal avoidance radiotherapy. We are hypothesizing that the use of functional magnetic resonance imaging (fMRI) in conjunction with neurological assessment, will result in a better understanding of Fraction Size Equivalent Dose (FED) levels (either maximum or mean FED), obtained from function specific dose volume histograms which lead to the impairment of a particular neurological function. Using the FED formalism one can reconvert BED values back to biologically equi-effective doses delivered at some standard dose-per-fraction, producing numbers that are more directly comparable with the dose-levels delivered using typical external beam schedules. Allowable FED levels that lead to minimal impairment of a particular neurological function could then be used in the design of image guided conformal avoidance radiotherapy treatment plans. The proposed research is based upon extensive preliminary data indicating that fMRI adds additional information about the location of eloquent volumes of brain responsible for the specific neurological functions (passive language comprehension (hearing), language, fine motor control, and vision) that can be incorporated into a radiation therapy treatment plan, with the goal of decreasing radiation injury to these areas. The Specific Aims of the project are: 1) To evaluate and quantify the reproducibility of fMRI maps of eloquent brain areas corresponding to specific neurological functions based on activation maps obtained with different thresholds in patients with benign and biopsy only low grade brain neoplasms. 2) To assess the impairment in neurological function in image guided intracranial radiotherapy using neurocognitive assessment tools and to derive dose response curves relating the impairment in a particular neurological function to the FED received by the area of eloquent brain corresponding to it.