Abstract
we applied an aperture adaptive technique with a visual guiding system to tackle the problem of respiratory motion. A homemade computer program showing a cyclic respiratory pattern was projected onto the ceiling to visually help the patient adjust their respiration. Once the respiratory motion became regular, the leaf sequence could be synchronized with the target motion. An oscillator was employed to simulate the patient’s breathing pattern. Two simple fields and one IMRT field were measured to verify the accuracy. Preliminary results showed that after appropriate training, the amplitude and duration of a volunteer’s breathing could be well controlled by the visual guiding system. The high dose gradient at the edges of the radiation fields were successfully retained. The aperture adaptive technique with the visual guiding system can be an inexpensive and feasible alternative without compromising delivery efficiency in clinical practice. this study was to develop a total body irradiation technique that does not require additional devices or sophisticated procedures to overcome the space limitation of a small treatment room by modifying the leaf sequences of intensity modulated fields.The technique treated the patient lying on the floor anteriorly and posteriorly. For each AP/PA treatment, two complementary fields with dynamic field edges were matched over an overlapped region defined by the marks on the body surface.The results confirmed that the technique is capable of delivering a uniform dose distribution to the midline of the body in a small treatment room while keeping the lung dose within the tolerance level.