5G05-Integrating Advanced Imaging and Radiotherapy Methods
C Clifton Ling, PhD
Departments of Medical Physics
Memorial Sloan Kettering Cancer Center
New York, NY 10021
Over the past century since the discoveries of Roentgen, Becquerel and Curie, there has been incredible progress in the use of ionizing radiation for cancer diagnosis and treatment. In radiotherapy, the clinical implementation of 3-dimensional conformal radiotherapy (3DCRT) and intensity-modulated radiotherapy (IMRT) will likely increase the effectiveness of this treatment modality. Within the past decade, IMRT has emerged, leading to further improvement in dose distribution conformality.
The "new" concept of IGRT (image-guided radiotherapy) may appear "retrograde" since from the very beginning radiotherapy has been image-based, in fact initially using the same X-ray equipment for diagnosis and therapy. However, the IGRT of the twenty-first century has its impetus in the concomitant but independent development of advanced imaging and radiotherapy methods, and indeed in the re-integration of imaging and treatment devices. Specifically, stereotaxic or volumetric imaging devices are now combined with radiation treatment units to provide image-guidance in real-time (or almost real-time). Perhaps the present approach would be more aptly called IG(RT)2, for radiotherapy with image-guidance in real-time.
Concomitant with the advances in radiation treatment, much development occurred in imaging, especially in CT, MRI and PET. Totally unanticipated until the last decade is the impact of the human genome project and the emerging possibility of imaging biological processes. Indeed, the spectacular advances in our understanding of cellular and molecular processes and their application to imaging are providing new types of images, with a wide spectrum of “biological” information, including metabolic, biochemical, physiological, functional and molecular (genotypic and phenotypic).
The improvement in the dose distribution conformality of IMRT, and the emerging ability of imaging that can give information about factors (e.g. tumor hypoxia, tumor burden) that influence radiosensitivity and treatment outcome, avail tremendous opportunities and bring new challenges. In this presentation I shall discuss some aspects of this ongoing synthesis of advances, in what some would say is “physics meets biology”.
5G05－先进的影像技术和放疗方法的结合
C Clifton Ling, PhD
Departments of Medical Physics
Memorial Sloan Kettering Cancer Center
New York, NY 10021
自从伦琴发现X射线、贝克勒尔发现放射性和居里夫人发现镭以来，在过去的一个多世纪里电离辐射在肿瘤诊断和治疗中的应用已经取得了巨大的进展。在放射治疗中，临床实施三维适形放射治疗（3DCRT）和调强放射治疗（IMRT）将很可能会改善肿瘤的疗效。在过去的十多年里，调强放射治疗（IMRT）的出现进一步改善了剂量分布的适形度。
图像引导的放射治疗（IGRT）这一“新”概念好像是有点旧词新意，因为放射治疗最初就是图像引导的，那时是使用同一个X线设备进行诊断和治疗。但是，二十一世纪的图像引导的放射治疗（IGRT）是源于同时但却独立发展起来的先进的影像技术和放射治疗方法，事实上它是成像和治疗设备的再次集成。特别是立体定向或容积成像设备与放射治疗设备相结合提供了实时（或几乎实时）的图像引导功能。或许目前的方法更应该被称之为图像引导的放射治疗（IGRT），即实时图像引导的放射治疗。
在放射治疗取得巨大进展的同时，影像技术也飞速发展，尤其是CT、MRI和PET等。更加令人始料不及的是在过去10多年里受人类基因组工程的影响出现的生物过程成像技术。的确，我们在对机体细胞和分子过程的理解及其在成像应用方面的巨大进步使新的成像方式成为可能，这一成像方式可以提供包括代谢、生化、生理、功能和分子（基因型和表现型）等大量的“生物学”信息。
调强放射治疗（IMRT）对剂量分布适形度的改善和新的成像技术（这些技术可以提供影响肿瘤放射敏感性和治疗效果的信息，比如肿瘤乏氧、肿瘤负荷等）的出现，为我们提供了巨大的机遇和新的挑战。本报告将讨论目前这方面（或许可以称之为“物理与生物结合”）的进展。