Subject(s)
Dose Fractionation, Radiation , Head and Neck Neoplasms/radiotherapy , Squamous Cell Carcinoma of Head and Neck/radiotherapy , Adult , Aged , Aged, 80 and over , Denmark/epidemiology , Female , Follow-Up Studies , Head and Neck Neoplasms/mortality , Humans , Male , Middle Aged , Norway/epidemiology , Squamous Cell Carcinoma of Head and Neck/mortality , Survival Analysis , Treatment OutcomeABSTRACT
An independent in vivo dose verification procedure for IMRT treatments of head and neck cancers was developed. Results of 177 intracavitary TLD measurements from 10 patients are presented. The study includes data from 10 patients with cancer of the rhinopharynx or the thyroid treated with dynamic IMRT. Dose verification was performed by insertion of a flexible naso-oesophageal tube containing TLD rods and markers for EPID and simulator image detection. Part of the study focussed on investigating the accuracy of the TPS calculations in the presence of inhomogeneities. Phantom measurements and Monte Carlo simulations were performed for a number of geometries involving lateral electronic disequilibrium and steep density shifts. The in vivo TLD measurements correlated well with the predictions of the treatment planning system with a measured/calculated dose ratio of 1.002+/-0.051 (1 SD, N=177). The measurements were easily performed and well tolerated by the patients. We conclude that in vivo intracavitary dosimetry with TLD is suitable and accurate for dose determination in intensity-modulated beams.
Subject(s)
Computer Simulation , Models, Biological , Radiotherapy Planning, Computer-Assisted/methods , Radiotherapy, Intensity-Modulated/methods , Thermoluminescent Dosimetry , Algorithms , Humans , Monte Carlo Method , Nasopharyngeal Neoplasms/radiotherapy , Phantoms, Imaging , Radiation Dosage , Radiometry/instrumentation , Reproducibility of Results , Thyroid Neoplasms/radiotherapyABSTRACT
OBJECTIVE: A retrospective review of all diagnosed cases of esthesioneuroblastoma registered in Denmark between 1978 and 2000 was carried out in order to obtain epidemiological data and optimize national treatment guidelines. MATERIAL AND METHODS: Forty cases were verified histologically and included in the analysis Epidemiological and histopathological data were evaluated in relation to the clinical outcome. RESULTS: The 40 cases represent an incidence rate of 0.4 cases/million inhabitants per year. Eight (20%) patients were classified as Kadish stage A, 13 (32.5%) as stage B and 19 (47.5%) as stage C. The histopathological findings were classified according to the grading system of Hyams The median follow-up time was 2.3 years (range 0.3-11.1 years). The 5-year crude survival rate was 61%, with a median survival of 3.1 years (range 0.3-19.2 years). The 5-year disease-free survival rate was 50%, with a median survival of 1.7 years (range 0-19.2 years). Only 3 (7%) patients had positive cervical lymph nodes at presentation. A nationwide consensus regarding treatment was seen in patients classified as Kadish stages A and B. The longest duration before the first recurrence of esthesioneuroblastoma was 5(1/2) years. CONCLUSIONS: The following therapeutic guidelines are suggested: Kadish stage A patients, surgical tumour resection and radiotherapy; Kadish stage B, surgical tumour resection and radiotherapy; Kadish stage C, surgical tumour resection via a craniofacial resection and radiotherapy combined with chemotherapy. Long-term follow-up of esthesioneuroblastoma patients is mandatory.
