Clinical and experimental observation of the length of time of respiratory phase: a preliminary study.

OBJECTIVE Our goal was to observe the duration of inhaling and exhaling as well as the inhalation to exhalation conversion in patients with lung cancer and experimental dogs. MATERIALS AND METHODS We recorded lung and tumor respiratory motion with X-ray camera, in five patients with lung cancer as well as in five experimental dogs. We made random observation of breathing cycle inhalation duration, exhalation duration, and inhalation to exhalation conversion within each lung cancer patients and within each of the five animals. RESULTS Respiratory inhalation duration of each dog and human > exhalation duration > exhale to inhale conversion length > inhalation to exhalation conversion length. During the four breathing cycles, the total respiratory duration differs, and the length of the same breathing phase is inconsistent. CONCLUSIONS The measurement of early stage breathing duration cannot be representative of breathing duration of the late stage. Radiation treatment planning system based on the pre-computed tomography scanning on the basis of early stage, there will be some radiation dose errors.