Individualized phantom based on CT slices and auxological data (ICTA) for dose estimations following radiotherapy for skin haemangioma in childhood

Background and purpose: Before 1974 about 5000 children were treated by radiotherapy at the Institut Gustave-Roussy (IGR) for a skin haemangioma. A human model whose characteristics are as close as possible to those of the patient at the time of the treatment is necessary to effectuate an accurate retrospective estimation of the radiation doses received at distant organs. Methods: We have developed a software package which constructs an individualized phantom based on CT slices and auxological data (ICTA) for this purpose. A set of real CT slices is used to produce a 3-D representation of the human body which is then adjusted to fit the dimensions supplied by published auxological data relative to sex and age for each patient. One hundred sixty-one anatomical landmarks of epidemiological interest have been defined inside the phantom for dose estimation. Results: The transverse, frontal and sagittal views of the phantom displayed permit accurate positioning of radioactive applicators. The software calculates the relevant parameters required for dose estimation based on the patient's probable anatomy.