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

• 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
• 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

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)以管理他们的 对于癌症，RT是成功的癌症治疗的重要组成部分。近年来，千伏和电力系统的使用 由于采用了图像引导放射治疗技术，MV成像得到了极大的提高。 当MV治疗射束开启时，肿瘤位置的直接成像具有改进的潜力 肿瘤靶向，导致更好的患者结果和减少对健康组织的照射。一个 另一种方法是使用实时千伏透视跟踪来执行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性水平。 MV电子射野成像设备(EPID)具有它们可以避免的明显优势 通过使用实际的MV治疗射束执行实时肿瘤跟踪，可获得超额成像剂量。 然而，MV EPID普遍存在画质不佳的问题。通常，一层薄的(&lt；1毫米) 闪烁体用于将x射线转换为可见光，然后由阵列非晶硅探测 (ASI)光电探测器。这些薄闪烁体的探测量子效率(Dqe)和铅含量非常低。 对比度噪声比较低的图像。 我们建议通过增加光子探测层来克服EPID对比度障碍 到10-50 mm，然后用一种特殊的 设计了光学摄像系统。假设是通过分析捕捉到的4D光场 从透明闪烁体，沿MV光束方向聚焦的2D平面可以 有效地重建了。因为对比度与吸收效率成线性关系，而吸收 与探测器厚度成线性关系，这种技术有可能通过以下方式增加DQE 比传统技术高出一个数量级。这项建议的目的是： 目标1-开发模拟和处理基于MV的光场的算法。 目的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/或自适应图像引导的放射治疗 而不增加非定向千伏剂量。