Radiation therapy treatment details – critical for care coordination – are typically available in radiation oncology electronic health record (EHR) modules, commonly recorded as free text notes, and manually entered into radiation therapy treatment summary documents. This may result in high clinician burden, transcription errors, and highlight lack of standardization in recording, generating, and sharing patients’ radiation therapy treatment summary reports. The summary documents are not available to other information systems and typically require manual querying of information to form a summary report. The summary information requires access to the radiation oncology information system which is not typically integrated into the “main” EHR. The CodeX Radiation Therapy Treatment Data (RTTD) project will develop, test and deploy open data standards and open application programming interfaces (APIs) that enable interoperable, multi-purpose exchange of radiation treatment summary data for care coordination and data reuse: such as quality management, research, and payer-required reporting. The project’s goal is to enable radiation oncology information systems to generate radiation therapy (RT) treatment summaries, using structured data elements, (e.g., end-of-treatment and in-progress summaries) that may be exchanged using FHIR. Using mCODE STU2 (Minimal Common Oncology Data Elements) as a foundation, the project defines profiles and value sets to create the RTTD model. Phase One: A radiation oncology information system generates an end of treatment summary report that can be retrieved by an information system. This phase includes structured data elements that will be collected to partially fulfill the end of treatment summary. This will be tested at the November 2021 Integrating Healthcare Enterprise – Radiation Oncology (IHE-RO) Connectathon. Phase Two: Consists of two key components: (1) defining new radiotherapy concepts in the RTTD IG that support in-progress RT summaries, and then implementing these mCODE profiles into information systems, in a test environment only, to test feasibility and (2) a proof of concept where a radiation oncology information system generates radiation therapy in-progress treatment summaries that can be retrieved by another information system, also taking place within a test environment. Phase Three: Production implementation of both in-progress and end-of-treatment summaries, including the creation, retrieval, and display in an EHR. Note: the pilot environment will be a testing (sandbox) environment using non-production systems and simulated patient data. Work products will include a FHIR IG – including radiotherapy profiles in mCODE, as well as supplemental profiles added in the RTTD IG. The IG will provide a set a rules for how FHIR resources should be used to enable the exchange of radiation therapy treatment data across information systems. For more information, go to: - RTTD public Confluence page: https://confluence.hl7.org/display/COD/Radiation+Therapy+Treatment+Data+for+Cancer - RTTD GitHub repository: https://github.com/HL7/codex-radiation-therapy - RTTD IG: http://build.fhir.org/ig/HL7/codex-radiation-therapy/branches/master/index.html - mCODE IG: http://hl7.org/fhir/us/mcode/2021may/index.html - CodeX public Confluence page: https://confluence.hl7.org/display/COD/CodeX+Home