This document provides specific requirements and guidance for the documentation of the physical behavior of an isocentric medical electron accelerator and other devices that are used for the purposes of a radiation treatment such as C-Arm Linear Accelerators. Tomotherapeutic, multiple fixed source, robotic arm, light and heavy ion and other radiation treatment devices are not covered in this version. This document does not claim full coverage of all configuration content. The scope is not intended to be comprehensive but to cover the majority of model conflict areas. This document does not describe all the requirements and testing which might be necessary to validate that a combined system is safe and effective for use. For example, output factors are considered part of the dose calculation model and not part of the physical model. The physical model parameters are within the scope of this document. Individual device manufacturers may have additional requirements beyond compliance to this document, including joint verification and validation of the combined system. Manufacturers are free to add additional private modules following the format described in Clause 4 for their own internal uses. These private tags are optional and shall be prefixed with “private_COMPANYNAME_” where COMPANYNAME is any self-chosen company name (that is, COMPANYNAME does not have to match the value of the tag “manufacturer_name” in the manufacturer macro). This document intends that the characteristics will be published or reported in an electronic template format that is defined herein. The template will be in XML format to facilitate interchange and digital comparison of the data (see Annex A). This document is intended to be used by medical device manufacturers and users in the field of radiation therapy.