Bone analogue phantoms: redefining standards in patient specific MRT dosimetry

在医疗系统发达的县，分子放射治疗(MRT)是一种相对常见的程序。在这一过程中，一种标记的放射性同位素被注射到体内，以便照射和杀死肿瘤细胞，同时保留周围健康的器官组织。仅在英国，就有大约200个部门每年进行超过11000次放射治疗，在大约28个欧盟国家进行约200,000次治疗。在个性化医疗的最新发展中，欧盟引入了一项新的第2013/59号指令，要求所有进行任何形式的放射治疗(包括MRT)的成员国必须在2018年2月6日之前提供每位患者的剂量治疗计划。尽管这听起来像是一种显而易见的情况，但实际上，MRT在临床上已经使用了大约75年，还没有完全建立的剂量学实践来计算输送到肿瘤靶点或危险器官的吸收剂量。尽管已就一般步骤达成一致，但目前用于确定剂量的图像的获取、质量和处理仍存在很大差异。因此，治疗方案往往是根据相对较少的患者的经验在当地发展起来的。尽管这些患者都接受过类似的给药活动，但特定器官受到的实际剂量可能会有很大的差异。由于涉及的复杂性，放射性核素剂量学的应用仅限于那些拥有开发内部技术的设施的学术团体。目前，很少有治疗中心能够将剂量计算验证到已知的精度水平，也只有少数学术治疗中心能够执行MRT蒙特卡罗(MC)计算。我们的团队成立于曼彻斯特大学和克里斯蒂博物馆之间，已经开发出在一个非常大的捷运实践中交付这一服务的能力。我们最近被选中领导欧盟在Emir MRT剂量测量项目(2016-19年)中根据模拟患者体模和物理3D打印体模进行剂量计算的工作。该项目将为临床实施MRT剂量计划提供一个标准化的欧洲框架。在我们的方法中，由STFC Mini-IPS赠款开发，3D打印的患者模拟(体模)是基于患者的CT图像构建的。这项新技术具有明显的潜力，可以为临床服务提供基础，为英国所有临床中心和MRT患者提供改进的活动量化基础。我们处于独特的地位，可以提供这项工作，可以访问基督教的MRT患者数据的大型数据库。使用这些数据，我们可以为建立未来的全国临床服务提供基础。克里斯蒂在MRT剂量学研究以及为提供MRT剂量学服务所需的国家临床服务(PET/CT)提供培训和支持方面拥有丰富的经验。此外，我们与业界有着密切的合作关系，特别是与领先的核医学工作站软件供应商爱马仕医疗解决方案有限公司。通过开发临床剂量学系统的全面验证方法，从而证明HERMES剂量学系统符合这一标准，我们的合作将能够为临床剂量学系统提供事实上的验证标准和市场领先的一揽子计划。这些链接提供了一条途径，将技术传播到更广泛的欧盟和国际核医学市场。反过来，这通过允许根据疾病反应修改治疗方法来改善患者结果，并通过最大化相同或减少的资源的结果而使医疗保健提供者受益。

Molecular Radiotherapy (MRT) is a relatively common procedure in counties with developed healthcare systems. In thisprocedure, a labelled radioisotope is administered to the body in order to irradiate and kill tumour cells whilst sparing thesurrounding healthy organ tissue. In the UK alone, there are some 200 departments performing over 11000 MRTs annuallyand ~200,000 therapies in some 28 EU countries.In a recent development towards personalised healthcare, a new EU directive 2013/59 was introduced which requires thatall Member states performing any form of radiotherapeutics (including MRT) must provide dosimetry treatment planning foreach patient by 6th February 2018. Although this may sound like an obvious situation, MRT has in fact been used clinicallyfor around 75 years with no fully established dosimetry practice for calculating the absorbed dose delivered to tumourtargets or to organs at risk. Even though the general steps have been agreed, there still exists a wide variation in thecurrent acquisition, quality and treatment of images used to determine dose. As a result, treatment protocols have oftenevolved locally, based on experience with a relatively small numbers of patients. Although such patients would all havereceived similar administered activities, the actual dose received to particular organs could have large variations.As a consequence of the complexities involved, the application of radionuclide dosimetry has been restricted to thoseacademic groups with the facilities to develop in-house techniques. Very few therapy centres currently can validate dosecalculations to a known level of accuracy and only a few academic therapy centres can perform MRT Monte Carlo (MC)calculations. Our group, established between The University of Manchester and The Christie, has developed the ability todeliver this within a very large MRT practice. We were recently selected to lead the EU work on validating dose calculations from simulated patient phantoms and physical 3D printed phantoms in the EMPIR MRTDosimetry project (2016-19). Theproject will provide a standardised European framework for clinical implementation of MRT dose planning. In our approach,developed with an STFC Mini-IPS grant, 3D-printed patient analogues (phantoms) are constructed based on patient CTimages. This novel technique has clear potential to provide the foundation of a clinical service to provide a basis forimproved activity quantification to all clinical centres and MRT patients in the UK.We are uniquely positioned to deliver this work, having access to a large data base of MRT patient data at The Christie.Working with these data, we can provide the foundation for establishing a future national clinical service. The Christie hasthe experience in both MRT dosimetry research and in providing training and support for a national clinical service(PET/CT) required to provide a MRT dosimetry service. In addition our collaboration has strong links with industry, inparticular Hermes Medical Solutions Ltd, a leading provider of nuclear medicine workstation software. By developing acomprehensive validation methodology for clinical dosimetry systems, and thereby demonstrating that the HERMESdosimetry system meets this standard, our collaboration will be able to provide a de-facto validation standard for clinicaldosimetry systems and a market leading package. These links provide a pathway to distribute the techniques to the widerEU and international nuclear medicine market. In turn, this improves patient outcomes by allowing modification of therapybased on disease response and also benefits the healthcare provider by maximising outcome for the same or reducedresource.