Design of a real-time dosimetry prototype for use with external beam radiotherapy

放射肿瘤学患者接受高度复杂的治疗，如强度调制放射治疗（IMRT），体积调制电弧治疗，立体定向放射外科和立体定向体放射治疗使用临床线性加速器。目前，放射治疗的质量保证（QA）并不依赖于累积剂量的先验测量，而累积剂量对时间光束调制并不敏感。因此，所提供治疗的实际质量和安全性是未知的，患者的不当行为无法被识别或纠正。我们假设，如果开发出用于外射束放疗的体内实时在线传输探测器，将可以防止放疗事故的发生，从而在治疗准确性、验证性、记录性和疗效方面取得较大的提高。该方案解决了体内实时传输检测器的迫切需求，为放射肿瘤学诊所提供了一种新的治疗验证和控制范例。这些在线、全时间检测器将提高患者在治疗期间的安全性，提高外部束流输送精度，提供实时治疗验证，实时检测偏离计划治疗，自动束流停止并在检测到错误时发出警告，自动QA程序和标准化，以及真实确定每个IMRT束流传递给患者的空间和时间影响。这种增强的影响将提高外部放射治疗的安全性和治疗准确性，这将改善50%癌症患者的治疗结果。仅在我们的诊所，这个数字估计每天就有270个病人。在圣路易斯的华盛顿大学和Best Medical Int。我们将采用高度集成的塑料封装辐射硬闪烁光纤和单片高增益光传感器，开发一种用于外束放疗的体内实时传输探测器。探测器的高通量电子器件由并行数据转换和并行数据采集集成电路构成。这种快速并行的电子接口能够实时检测分娩过程中的治疗错误，并在患者健康受到损害时相应地纠正或暂停治疗。商业上可行的探测器原型将使用外部光束QA和拟人化模型进行验证，提供头颈部和肺癌的治疗计划，并根据这两个癌症部位的实时治疗验证制定患者QA方案。所提出的成像剂量仪可以应用于其他恶性肿瘤和治疗的实时验证，但在本项目中，我们将集中在这两个地点作为该技术实施的模型和验证，以提高当前临床实践中外束放疗的安全性和治疗效果。该技术的低成本和自主能力使其实现简单，适用于大型和小型临床手术。

Radiation oncology patients receive highly complicated treatments such as intensity modulated radiation therapy (IMRT), volumetric modulated arc therapy, stereotactic radiosurgery and stereotactic body radiation therapy using clinical linear accelerators. Currently, the quality assurance (QA) of a radiation treatment is don a priori to measure cumulative doses, which is not sensitive to temporal beam modulation. Therefore, the actual quality and safety of the delivered treatment is unknown and patient mistreatment cannot be identified or corrected. We hypothesize that if in vivo real time on line transmission detectors for external beam radiotherapy are developed, radiotherapy accidents will be prevented to achieve considerable improvement in treatment accuracy, verification, recording, and efficacy. This proposal addresses the urgent need for in vivo real time transmission detectors to provide radiation oncology clinics a novel treatment verification and control paradigm. These online, all time detectors will increase patient safety during treatment by improving external beam delivery accuracy, providing real time treatment verification, real time detection of departures from planned treatments, automatic beam halting and warnings if errors are detected, automatic QA procedures and standardization, and true determination of the spatial and temporal fluence delivered to the patient by each IMRT beam. The impact of this enhancement will improve external beam radiotherapy safety and treatment accuracy, which will improve the treatment outcome for 50% of cancer patients. In our clinic alone, this number is estimated to be 270 patients per day. In a consortium between Washington University in Saint Louis and Best Medical Int., we will develop an in vivo real time transmission detector for external beam radiotherapy using highly integrated plastic encapsulated radiation hard scintillating fibers and monolithic high gain photosensors. The high throughput electronics of the detector are constructed using parallel data conversion and parallel data acquisition integrated circuits. This fast and parallel electronic interface is capable of detecting treatment errors during delivery in real time and accordingly correct or suspend a treatment if patient health is compromised. The commercially viable detector prototype will be validated using external beam QA and anthropomorphic phantoms, delivering treatment plans for head and neck and lung cancer and formulating patient QA protocols based on real time treatment verification of these two cancer sites. The proposed imaging dosimeter can be applied to real time verification of other cancer malignancies and treatments, but in this project we will concentrate on these two sites as models and validation for the implementation of this technology to enhance the safety and therapeutic efficacy of external beam radiotherapy in current clinical practice. The low cost and autonomous capability of the proposed technology makes its implementation simple and adaptable for large and small clinical operations.