End-to-end dosimetry audit for SRS/SBRT: optional or mandatory at the beginning of the journey?

Experience of RTsafe succeSRS/SBRT implementation for Varian Halcyon machine.

This presentation focuses on the implementation of end-to-end dosimetry audits for SRS/SBRT treatments using the RTsafe independent audit system on a Varian Halcyon machine.

SRS/SBRT are advanced radiotherapy techniques that deliver very high ablative doses of radiation, with great accuracy, precision and conformality. As we know, in radiotherapy, even small errors in the acquisition of CT images for simulation, in planning, dosimetry, treatment delivery, or patient positioning can lead to negative consequences.

Given the high-dose gradients and submillimeter accuracy required in stereotactic radiotherapy, the audit evaluates the entire treatment chain – from imaging and target definition to planning, delivery and dose verification. The role of such audits in detecting geometric and dosimetric uncertainties is highlighted, along with their contribution to ensuring treatment accuracy, consistency and patient safety in high-precision radiotherapy. Last but not least, especially at the beginning of the implementation of these techniques in a new radiotherapy department, the audit can also help to validate the specific procedures for SRS/SBRT and the professional training for the members of the treatment team.

Florin Costache is a medical physicist expert in radiotherapy across multiple clinics, while also serving as a radiation safety officer, with more than 20 years of professional activity in clinical and academic environments. Throughout his career, he has worked in leading radiotherapy centers in Romania, contributing to commissioning, quality assurance, dosimetry and advanced treatment planning using modern systems such as Varian platforms. Florin’s expertise spans advanced radiotherapy techniques, radiation safety and the implementation of quality assurance systems in clinical practice.

In addition to his clinical work, Florin is a lecturer, course coordinator and former president of the Romanian Medical Physics Society, with numerous scientific publications and conference presentations.