Bolus materials are commonly used for both human and veterinary radiation therapy (RT). Commercially available bolus materials often leave an air gap between the bolus and the skin which can lead to underdosing of the tumor. This prospective exploratory study evaluated the 6 MV X‐ray and electron beam (6, 9, and 12 MeV) attenuating properties for two alternative bolus materials: McKesson lubricating jelly® (MLJ) and Aquasonic 100 Ultrasound gel® (AUG). The results comparing MLJ and water for 12 MeV and 9 MeV electron beams showed <3% difference, however, no other significant differences in radiation dose between water and MLJ nor AUG were seen. Findings demonstrated that both AUG and MLJ have radiation dose attenuating properties similar to water and supported use of these materials as alternative bolus materials for veterinary radiation therapy applications.

ObjectiveThe aim of this study was to describe the therapeutic outcomes of dogs with locally advanced salivary gland carcinomas (SGC) following stereotactic body radiation therapy (SBRT).MethodsA single institution retrospective study was conducted of client-owned dogs with macroscopic SGC treated with SBRT. Patient signalment, clinical characteristics, and treatment parameters were recorded. Clinical benefit was determined based on follow-up physical examination and medical history. Progression-free interval (PFI), median survival time (MST), and disease-specific survival (DSS) were calculated using Kaplan–Meier analysis. Acute and late toxicity were recorded according to Veterinary Radiation Therapy Oncology Group (VRTOG) criteria.ResultsSix patients were included in the study. Tumor origins were mandibular (n = 3), parotid (n = 2), and zygomatic (n = 1) salivary glands. The SBRT prescription was 10 Gy × 3 daily or every other day. All patients (100%) experienced clinical benefit from treatment at a median time of 34 days (range 28–214). No local or regional nodal failure was reported following SBRT. Progressive pulmonary metastatic disease was documented in three dogs (50%). The median PFI was 260 days (range 43–1,014) and the MST was 397 days (range 185–1,014). Median DSS was 636 days (range 185–1,014). Four dogs (66.6%) died of confirmed or suspected metastatic SGC. The reported acute side effects included grade 2 mucositis (n = 1) and vision loss (n = 1). No late side effects were recorded.ConclusionThis study suggests that SBRT may provide durable local control for invasive SGC in dogs. Further investigation in a larger cohort of patients is warranted. The incidence of reported acute and late toxicity was low.

In collaboration with the American College of Veterinary Pathologists