Dental Radiation Dosimetric Maps using American Numbering System from Intensity Modulated Radiation Therapy (IMRT) Planning for Head and Neck Cancers

Dental professionals often request radiation doses to teeth, maxillae and mandibles from radiation oncologists who treat cancers of the head and neck. This frequently occurs before patients undergo CT simulation, precluding precise dose calculations. The purpose of this study was to create dental radiation maps to provide to dental professionals the mean RT dose to teeth, maxilla and mandible for commonly treated primary head and neck cancers using intensity modulated radiation therapy (IMRT). Twenty-seven common clinical settings were chosen. Examples include cT2N1 SCC of the left tonsil, pT1N0 SCC of the floor of mouth s/p surgical resection and a cT2N0 SCC of the supraglottic larynx, among others. Patients had received prior curative radiation treatment using IMRT, either in the definitive or adjuvant setting. Radiation plans were extracted from ‘Velocity’ planning software. Each tooth was contoured and labeled at the junction of the tooth and the gingiva based on the Universal numbering system (American System). In addition, left lateral 3rd, middle 3rd and right lateral 3rd of the mandible and maxilla were contoured. Dosimetric data for each tooth and third of the mandible and maxilla were obtained. Dose wash images in axial, sagittal and coronal were also captured for each plan. All twenty-seven patients were treated with prescribed doses of 60-70Gy in 1.8-2Gy/fxn using dose painting IMRT. Tables with mean doses to each 3rd of the mandible and maxilla, along with each tooth labeled 1-32, were created. Nine patients received mean doses >50Gy to at least 1 tooth, 4 patients had portions of the maxilla with mean doses >50Gy and 8 patients had portions of the mandible with mean doses >50Gy. We believe this to be the first study generating dental radiation dosimetric maps of estimated doses to each tooth and each third of the mandible and the maxilla for common examples of head and neck cancer faced by radiation oncologists. Adoption of these dental maps may help improve clinical workflow efficiency for dental providers and radiation oncologists by providing estimates of dental doses for common primary head and neck cancers. T both for patients pending future radiation treatment and for previously irradiated patients when radiation plans are not available.Abstract 3775; TableTooth #12345678910111213141516Mean dose (Gy)26.8723.1520.5418.2417.8215.2715.4716.0916.9720.8926.4030.3332.8436.8348.1758.2627.9829.0229.6428.4223.5318.3316.5815.9715.8316.3819.8325.8333.6743.7452.960.83Tooth #32313029282726252423222120191817MandibleMaxillaLeft Lateral 3rdMiddle 3rdRight Lateral 3rdLeft Lateral 3rdMiddle 3rdRight Lateral 3rd56.84 Gy23.01 Gy19.30 Gy44.71 Gy18.82 Gy22.15 Gy Open table in a new tab