Helical tomotherapy and two types of volumetric modulated arc therapy: dosimetric and clinical comparison for several cancer sites

AbstractRadiotherapy accelerators have undergone continuous technological developments. We investigated the differences between Radixact ™ and VMAT treatment plans. Sixty patients were included in this study. Dosimetric comparison between the Radixact™ and VMAT plans was performed for six cancer sites: whole-brain, head and neck, lymphoma, lung, prostate, and rectum. The VMAT plans were generated with two Elekta linear accelerato rs (Synergy® and Versa HD™). The planning target volume (PTV) coverage, organs-at-risk dose constraints, and four dosimetric indexes were considered. The deliverability of the plans was assessed using quality assurance (gamma index evaluation) measurements; clinical judgment was included in the assessment. T he mean AAPM TG218 (3%–2 mm, global normalization) gamma index values were 99.4%, 97.8%, and 96.6% for Radixact™, Versa HD™, and Synergy®, respectively. Radixact™ performed better than Versa HD™ in terms of dosimetric indexes, hippocampiD100%, spinal cordDmax, rectumV38.4   Gy, bladderV30 Gy,  andV40 Gy. Versa HD ™ saved more of the (lungs-PTV)V5 Gy and (lungs-PTV)Dmean,  heart Dmean, breastsV4 Gy, and bowel V45 Gy. Regarding  Synergy®, the head and neck  Radixact™ plan saved more of the parotid gland, oral cavity, and supraglottic larynx. From a clinical point of view, for the head and neck, prostate, and rectal sites, the Radixact™ and Versa HD™ plans were similar; Radixact™ plans were preferable fo...
Source: Radiological Physics and Technology - Category: Physics Source Type: research