The use of electronic portal imaging devices for the dosimetric verification of complex radiotherapy treatments

被诊断患有癌症的人的预后比通常认为的要好得多。如果发现得早，恶性肿瘤通常能很好地定位。在肿瘤生长的早期阶段，高剂量的放射治疗有很大可能根除癌症，但代价是对正常组织造成不可接受的损害。改进放射治疗技术的一个具体目标是减少对正常组织的损伤可能性。实现这一目标可能允许更高剂量的注射，从而增加控制肿瘤的机会。放射治疗面临的挑战之一是肿瘤的形状不容易治疗。肿瘤延伸到腔内，把健康的器官推到一边，形成复杂的3D形状。仔细塑造辐射束以提供与目标的3D形状相匹配的剂量分布被称为3D适形放疗（3DCRT）。强度调制放疗（IMRT）是3DCRT的一种高级形式，它允许根据复杂肿瘤体积的形状密切定制递送剂量，同时不影响邻近的健康组织。增加放射治疗的一致性的后果之一是增加了对治疗准备和执行中的错误的敏感性。如果要实现使用3DCRT和IMRT技术治疗结果的最大增益，那么在治疗的每一天将正确的体积治疗到正确的剂量是至关重要的。这需要新的改进方法和技术来验证每天的治疗交付。在这个项目中，我们的目标是开发在线数字成像设备的使用，以测量治疗期间的剂量。这将增加人们对这些新的适形放疗技术的信心，使其真正的潜力能够改善患者的治疗结果。

The prognosis for someone diagnosed with cancer is much better than commonly believed. If detected early, malignant tumours are generally well localised. During these early stages of tumour growth high doses of radiation therapy can with a high probability, eradicate a cancer but come with the cost of causing unacceptable damage to normal tissue. A specific goal of improving the technology of radiation therapy is to reduce the probability of damage to normal tissue. Achieving this goal may allow delivery of higher doses with an associated increase in the chance of controlling the tumour. One of the challenges in radiation therapy is that tumours do not come in shapes that are easy to treat. Tumours extend into cavities and push aside healthy organs growing into complex 3D shapes. The careful shaping of the radiation beams to deliver dose distributions that match the 3D shape of the target is known as 3D conformal radiotherapy (3DCRT). Intensity Modulated Radiotherapy (IMRT) is an advanced form of 3DCRT that allows the delivered dose to be closely tailored to the shape of complex tumour volumes while sparing neighbouring healthy tissues. One of the consequences of increasing the conformality of radiation therapy is an increased sensitivity to errors in the preparation and execution of the treatment. If the maximum gain in the treatment outcome using 3DCRT and IMRT techniques is to be achieved then it is crucial that the correct volume is treated to the correct dose on each day of the treatment. This requires new improved methods and techniques for verifying the daily delivery of the treatment. In this project we aim to develop the use of online digital imaging devices for measuring the delivered dose during treatment. This will increase the confidence with which these new conformal radiotherapy techniques can be delivered allowing their true potential for improving patient treatment outcomes to be realised.