Patient follow-up after high dose fluoroscopically-guided interventional (FGI) procedures is a critical component of quality patient care and is also now a requirement for some regulatory bodies and standards organizations. To establish appropriate follow-up policies and procedures, one must first understand the radiation dose metrics commonly available on fluoroscopic systems, such as the reference point air kerma and air kerma-area product. It is also important to understand the relationship between the commonly used metrics and the absorbed dose to relevant structures within the human body. Auxiliary biological metrics used for the comparison of alternate fractionation schedules in external beam radiation therapy (EBRT), such as the equivalent dose in 2 Gy fractions (EQD2), may also be useful for comparing the toxicity from multiple FGI procedures.
In the first talk of this session (â€œDosimetric and Radiobiologic Challengesâ€?), the concepts of reference point air kerma and the air kerma-area product will be reviewed and related to the absorbed dose to the skin.
The second talk of this session (â€œComparative Radiobiology of Fluoroscopically-guided Interventions (FGI) and EBRTâ€?) will review key radiobiological concepts underlying treatment toxicity arising from individual and multiple FGI procedures. To assess the potential risks of FGI procedures, the EQD2 for organ at risk (OAR) plan constraints from EBRT treatments and FGI procedures will be compared.
The final talk of this session (a Case Report â€“ Future Directions and Opportunities) will discuss a clinical scenario in which a patient received dose from multiple FGI procedures as well as an EBRT treatment. This case review will be used to highlight additional patient care challenges and opportunities.
1. Review basic radiation metrics and terminology associated with fluoroscopic radiation doses
2. Discuss several different clinical scenarios resulting in patients receiving high radiation doses
3. Review basic radiobiological principles and related biological metrics, such as EQD2
4. Illustrate the use of the EQD2 concept with corrections for dose rate, relative biological effectiveness (RBE) of kV x-rays relative to MV x-rays, dose per procedure and tissue recover between procedures for comparative assessments of the risks from FGI procedures and EBRT treatments