Virtual Simulation of Bone Metastases by a Dedicated Palliative Radiation Therapist: A Retrospective Comparison Pilot...

In interdisciplinary teams, members may take on responsibilities usually performed by others to enhance patient care. In the Rapid Access Palliative Radiotherapy Program, a dedicated radiation therapist (MRT[T]) participates in clinical assessments, team conferences, patient education, simulation, treatment delivery, and follow-up. The purpose of this study was to determine the feasibility of virtual simulation performed by an MRT(T) experienced in treating bone metastases within this specialized clinic.

After radiotherapy was planned by a radiation oncologist (RO) and administered, the 3-dimensional dataset was duplicated and anonymized. In a blinded fashion, patients were independently retrospectively simulated by one MRT(T) with access to the patient's clinical and radiological information. Resulting digitally reconstructed radiographs were compared with actual simulation films. Summary statistics were compiled to quantify differences in field size (FS) and isocenter placement.

Twelve bone metastases were treated (6 spine, 4 hip, 2 shoulder) with either a direct posterior or parallel opposed arrangement. For 11 of the 12 sites, beam arrangements chosen by the MRT(T) and the RO were the same. Shielding was added to 3 of the 12 sites by the RO and 2 of the 12 by the MRT(T). For the sites with a similar field arrangement, there was no significant difference between mean blocked RO (133.6 cm² [SD 52.6 cm]) and MRT(T) field sizes (129.3 cm² [SD 47.4 cm]) (P = .52). On average, the MRT(T) plan resulted in 4.3 cm² undercoverage compared with the treatment FS. Isocenter placement differed on average by 0.25 cm laterally, 0.02 cm anteriorly, and 0.15 cm inferiorly for MRT(T) versus RO fields. One of 11 sites virtually planned by the MRT(T) was a geographic miss of a soft-tissue mass.

In this study, an MRT(T) member of a dedicated interdisciplinary team piloted virtual simulation for bone metastases treatment. Although average FS and isocenter placement did not significantly differ, optimal radiotherapy of complex bone metastases likely requires a collaborative approach.