Time evaluation of image-guided radiotherapy in patients with spinal bone metastases

Time is an important factor during immobilization for radiotherapy (RT) of painful spinal bone metastases. The different RT techniques currently in use have differing impacts on medical staff requirements, treatment planning and radiation delivery. This prospective analysis aimed to evaluate time management during RT of patients with spine metastases, focusing particularly on the impact of image-guided RT (IGRT). Between 21 March 2013 and 17 June 2013, we prospectively documented the time associated with the core work procedures involving the patient during the first day of RT at three different linear accelerators (LINACs). The study included 30 patients; 10 in each of three groups. Groups 1 and 2 were treated with a single photon field in the posterior-anterior direction; group 3 received a three-dimensional conformal treatment plan. The median overall durations of one treatment session were 24 and 25.5 min for the conventional RT groups and 15 min for IGRT group. The longest single procedure was patient immobilization in group 1 (median 9.5 min), whereas this was image registration and matching in groups 2 and 3 (median duration 9.5 and 5 min, respectively). Duration of irradiation (beam-on time) was similar for all groups at 4 or 5 min. The shortest immobilization procedure was observed in group 3 with a median of 3 min, compared to 4 min in group 2 and 9.5 min in group 1. With this analysis, we have shown for the first time that addition of modern IGRT does not extend the overall treatment time for patients with painful bone metastases and can be applied as part of clinical routine in a palliative setting. The choice of treatment technique should be based upon the patient's performance status, as well as the size of the target volume and location of the metastasis.