Intracranial Conformal Avoidance Radiation Therapy

描述（由申请人提供）：本申请要求支持确定强度调节放疗（IMRT）治疗计划过程的分数大小等效剂量（FED）水平，仅用于良性和活检的低级别脑肿瘤，这些肿瘤导致被动语言理解（听力），语言，精细运动控制和视觉感知（视觉）等特定神经功能的低损伤。因此，在光学引导适形回避放射治疗中，可以保留这些区域。我们假设将功能性磁共振成像（fMRI）与神经学评估结合使用，将更好地理解从功能特定剂量体积直方图中获得的分数大小等效剂量（FED）水平（最大或平均FED），从而导致特定神经功能的损害。使用FED的形式，我们可以将BED值重新转换回以某种标准剂量/分数传递的生物等效剂量，从而产生与使用典型外部光束时间表传递的剂量水平更直接可比的数字。允许的FED水平导致特定神经功能的最小损害，然后可以用于图像引导适形回避放射治疗计划的设计。

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.