Enhanced megavoltage imaging for radiotherapy by light-field imaging of scintillators

通过闪烁体光场成像增强放射治疗兆伏电压成像

基本信息

批准号：
9924560
负责人：
Patrick Jean La Riviere
金额：
$ 19.65万
依托单位：
UNIVERSITY OF CHICAGO
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-06-01 至 2022-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9924560
关键词：
3-Dimensional Adoption Affect Algorithms American Anatomy Cancer Control Cancer Patient Clinical Crystallization Deposition Detection Development Diagnostic Dose Evaluation Exposure to Eye Frequencies Glass Goals Gold Image Image Analysis Imaging Device Imaging Phantoms Lead Light Linear Accelerator Radiotherapy Systems Liver Lung Malignant Neoplasms Methods Modeling Monitor Motion Noise Normal tissue morphology Operative Surgical Procedures Optics Patient-Focused Outcomes Patients Pattern Photons Positioning Attribute Process Property Prostate Radiation Radiation therapy Resolution Roentgen Rays Seeds Silicon Skin Specificity System Techniques Testing Therapeutic Thick Thinness Time Tissues Visible Radiation Work absorption algorithm development base bone cancer imaging cancer radiation therapy cancer therapy chemotherapy clinical practice cost design detector dosimetry image guided radiation therapy image reconstruction imager improved irradiation nanoparticle novel novel strategies photon-counting detector quantum reconstruction research clinical testing simulation tumor

项目摘要

With more than 50% of all patients receiving radiation therapy (RT) for the management of their cancers, RT is an essential part of a successful cancer treatment. In recent years, the use of kV and MV imaging has greatly increased due to the adoption of image-guided radiation therapy techniques. Direct imaging of the tumor position while the MV treatment beam is ON has potential for improving tumor targeting, leading to better patient outcomes and reduced irradiation of healthy tissues. An alternative method employs real-time kV fluoroscopic tracking to perform 3D tumor-position tracking. However, this method can only be used for short periods of time as excess imaging dose can quickly exceed patient skin-dose tolerance levels. MV electronic portal imaging devices (EPID) have the distinct advantage that they can avoid this excess imaging dose by performing real-time tumor tracking using the actual MV treatment beam. However, MV EPIDs generally suffer from poor image quality. Typically, a thin (<1 mm) layer of scintillator is used to convert x-rays to visible light that is then detected by an array amorphous silicon (aSi) photodectors. These thin scintillators have very low detective quantum efficiency (DQE) and lead to images with poor contrast-to-noise ratios. We propose to overcome the EPID contrast obstacle by increasing the photon detection layer to 10-50mm using a transparent scintillator and then capturing its 4D light field using a specially designed optical camera system. The hypothesis is that by analyzing the 4D light field captured from a transparent scintillator, in-focus 2D planes along the MV beam direction can be effectively reconstructed. As contrast is linearly proportional to absorption efficiency, and absorption is linearly proportional to detector thickness, this technique has the potential to increase DQE by an order of magnitude over conventional techniques. The aims of the proposal are: Aim 1 – Development of algorithms for simulating and processing MV based light fields. Aim 2 – Experimental evaluation of a MV based light field camera. If successful, the approach will enable realtime and/or adaptive image-guided radiation therapy without addition of untargeted kilovoltage dose.

超过 50% 的患者接受放射治疗 (RT) 来控制病情近年来，使用 kV 和 RT 来治疗癌症，RT 是成功癌症治疗的重要组成部分。由于采用图像引导放射治疗技术，MV 成像大大增加。 MV 治疗光束打开时肿瘤位置的直接成像具有改善的潜力肿瘤靶向，带来更好的患者治疗效果并减少健康组织的照射。另一种方法采用实时 kV 透视跟踪来执行 3D 肿瘤位置跟踪。然而，这种方法只能在短时间内使用，因为过量的成像剂量会很快超过患者皮肤剂量耐受水平。 MV 电子射野成像设备 (EPID) 具有明显的优势，可以避免通过使用实际 MV 治疗光束进行实时肿瘤跟踪来消除多余的成像剂量。然而，MV EPID 通常存在图像质量较差的问题，通常是薄层（<1 毫米）。闪烁体用于将 X 射线转换为可见光，然后由阵列非晶硅检测到 (aSi) 光电探测器具有非常低的探测量子效率 (DQE) 和铅。对比度与噪声比较差的图像。我们建议通过增加光子检测层来克服 EPID 对比障碍使用透明闪烁体到 10-50mm，然后使用特殊的捕获其 4D 光场设计的光学相机系统的假设是通过分析捕获的4D光场。从透明闪烁体，沿 MV 光束方向的聚焦 2D 平面可以是由于对比度与吸收效率和吸收成线性比例。与探测器厚度成线性比例，该技术有可能将 DQE 提高比传统技术高出一个数量级该提案的目标是：目标 1 – 开发用于模拟和处理基于 MV 的光场的算法。目标 2 – 基于 MV 的光场相机的实验评估。如果成功，该方法将实现实时和/或自适应图像引导放射治疗无需添加非目标千伏剂量。