A gated breath-hold radiotherapy technique using a linear position transducer

For patients with thoracic and abdominal lesions, respiration-induced internal organ motion and deformations during radiation therapy are limiting factors for the administration of high radiation dose. In order to escalate the dose to the tumor and reduce the treatment margins, the tumor movement during treatment must be minimized. In our approach we have established a largely automated deep-breath-hold technique for treating lung cancer patients. We have used a Linear Position Transducer to monitor tumor movement through changes in the patient's abdominal cross-sectional area. The technique aims to reduce the amount of healthy lung tissue in high-dose regions. Normal tissue can be spared as a result of two distinct features of this method: deep inspiration, which reduces the lung density, and breath hold, which immobilizes the tumor. Due to reduced tumor motion, the Planning Target Volume margins can be tightened and a higher dose of radiation can be delivered to the tumor with the same risk of normal tissue complications