Intracranial Conformal Avoidance Radiation Therapy

描述（申请人提供）：本申请要求支持确定良性和仅活检的低级别脑肿瘤的调强放疗（IMRT）治疗计划过程的分数大小等效剂量（FED）水平，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（视力）等特定神经功能的轻度损伤，因此允许在光学引导的适形避免放射治疗期间保留这些区域。 我们假设，使用功能性磁共振成像（fMRI）结合神经系统评估，将导致更好地了解分数大小等效剂量（FED）水平（最大或平均FED），从功能特定剂量体积直方图中获得，导致特定神经功能受损。 使用FED形式主义，可以将BED值重新转换回以某个标准剂量每部分递送的生物等效剂量，产生与使用典型外部射束时间表递送的剂量水平更直接可比的数字。 允许的FED水平，导致一个特定的神经功能的损害最小，然后可以用于设计图像引导的适形避免放射治疗计划。 拟议的研究是基于广泛的初步数据，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）的大脑功能区位置的额外信息，这些信息可以纳入放射治疗计划，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)在良性和仅活检的低级别脑肿瘤患者中，基于以不同阈值获得的激活图，评价和量化与特定神经功能对应的功能脑区的fMRI图的可重复性。 2)使用神经认知评估工具评估图像引导颅内放射治疗中的神经功能损伤，并推导出特定神经功能损伤与相应功能脑区接受的FED相关的剂量反应曲线。

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.