Tomoki Kimura MD, Presenter: Nothing to Disclose

Yuji Murakami MD, Abstract Co-Author: Nothing to Disclose

Masahiro Kenjo, Abstract Co-Author: Nothing to Disclose

Yuko Kaneyasu MD, Abstract Co-Author: Nothing to Disclose

Koichi Wadasaki MD, Abstract Co-Author: Nothing to Disclose

Katsuhide Ito MD, Abstract Co-Author: Nothing to Disclose

Purpose/Objective: We have developed a voluntary breath-hold method using spirometer-based monitoring to reduce respiratory motion in the treatment of lung tumors and verified the reproducibility of organ position in normal volunteers. From January 2003, we have applied this method to stereotactic radiotherapy of lung tumors, clinically. The purpose of this study was to evaluate the reproducibility of gross tumor volume (GTV) and diaphragm position in a clinical setting. Materials/Methods: In this analysis, 9 patients who had 11 lung tumors were enrolled. To familiarize them with the procedure, they were given training sessions. Patients held their breath at the end-expiration phase or the end-inspiration phase under spirometer-based monitoring. To evaluate the intrafraction reproducibility of GTV center, planning CT scans were performed twice with a 5-minute interval at the same respiratory phase. All GTVs were delineated by a physician and GTV centers were defined as the centers of maximal axis at the central slice of GTVs. To evaluate the intrafraction and the interfraction reproducibility of the diaphragm, we compared diaphragm position relative to bony landmarks and the isocenter. The reproducibility was defined as the average of difference from beams eye view (BEV) and each linacgraphy (LG.). We also compared with caudal-cranial (CC) distance of GTV and diaphragm position at free breathing and breath-holding phase. Results: Twenty two planning CT scans and 62 fractions of stereotactic radiotherapy were analyzed in this study. Seven patients who had 8 tumors held their breath at the end-expiration phase and 2 patients who had 3 tumors held their breath at the end-inspiration phase. The intrafraction reproducibility of GTV centers was 2.5±2.9mm (mean and standard deviation), 1.3±0.6mm, and 1.6±1.3mm in CC, medial-lateral (ML), and anterior-posterior (AP) direction, respectively. The intrafraction reproducibility of the diaphragm position was 2.3±1.6mm, 2.0±1.5mm, and 1.6±1.5mm in CC, ML, and AP direction, respectively. The interfraction reproducibility of the diaphragm position was 3.2±2.1mm, 1.9±1.6mm, and 1.6±1.9mm in CC, ML, and AP direction, respectively. The CC distance of GTV and the diaphragm at free breathing and breath-holding phase was 34.1±15.1mm and 25.7±11.9mm, 13.2±3.6mm and 2.3±0.9mm, respectively. The CC distance of the diaphragm was significantly better at the breath-holding phase than at free breathing (p<0.01). The reproducibility of GTV center and diaphragm position was not significant between the end-expiration and the end-inspiration phase. Conclusions: Treatment of patients with voluntary breath-hold method using a spirometer was feasible and non-invasive in a clinical setting. The reproducibility of GTV centers and diaphragm position with this method was relatively good, and diaphragm motion could be significantly reduced. This method is useful for the reduction of internal margin and high-dose irradiated normal lung volume in stereotactic radiotherapy of lung tumors.

Kimura, T, Murakami, Y, Kenjo, M, Kaneyasu, Y, Wadasaki, K, Ito, K, Clinical Experience of Voluntary Breath-hold Method Using a Spirometer during Stereotactic Radiotherapy for Lung Tumors: Physical Aspects.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4417859.html