American Association of Physicists in Medicine Task Group 263: Standardizing Nomenclatures in Radiation Oncology

Abstract

A substantial barrier to the single- and multi-institutional aggregation of data to supporting clinical trials, practice quality improvement efforts, and development of big data analytics resource systems is the lack of standardized nomenclatures for expressing dosimetric data. To address this issue, the American Association of Physicists in Medicine (AAPM) Task Group 263 was charged with providing nomenclature guidelines and values in radiation oncology for use in clinical trials, data-pooling initiatives, population-based studies, and routine clinical care by standardizing: (1) structure names across image processing and treatment planning system platforms; (2) nomenclature for dosimetric data (eg, dose-volume histogram [DVH]-based metrics); (3) templates for clinical trial groups and users of an initial subset of software platforms to facilitate adoption of the standards; (4) formalism for nomenclature schema, which can accommodate the addition of other structures defined in the future. A multisociety, multidisciplinary, multinational group of 57 members representing stake holders ranging from large academic centers to community clinics and vendors was assembled, including physicists, physicians, dosimetrists, and vendors. The stakeholder groups represented in the membership included the AAPM, American Society for Radiation Oncology (ASTRO), NRG Oncology, European Society for Radiation Oncology (ESTRO), Radiation Therapy Oncology Group (RTOG), Children's Oncology Group (COG), Integrating Healthcare Enterprise in Radiation Oncology (IHE-RO), and Digital Imaging and Communications in Medicine working group (DICOM WG); A nomenclature system for target and organ at risk volumes and DVH nomenclature was developed and piloted to demonstrate viability across a range of clinics and within the framework of clinical trials. The final report was approved by AAPM in October 2017. The approval process included review by 8 AAPM committees, with additional review by ASTRO, European Society for Radiation Oncology (ESTRO), and American Association of Medical Dosimetrists (AAMD). This Executive Summary of the report highlights the key recommendations for clinical practice, research, and trials.

Fig. 1.

Illustration of a section of the nomenclature list worksheet for nontarget structures. Each column allows sorting and searching by clicking on the down arrow to the right of the heading as shown in the zoomed region.

Fig. 2.

Illustration of standardized dose–volume histogram nomenclature specifying input and output units. Approach is compatible with use of regular expressions.

Fig. 3.

Illustration of dose–volume histogram differences when using segmented planning target volume (PTV) definitions, where the high-dose PTV (PTV_High, red curve) is not included as part of a lower dose PTV (PTV_Low, blue curve) compared with a nonsegmented approach, where the high-dose PTV is included in the lower dose PTV (PTV_Low, green curve). In this example, the volume of PTV_High is 55% of the volume of the nonsegmented PTV_Low.