Interbreath-hold reproducibility of lung tumour position and reduction of the internal target volume using a voluntary breath-hold method with spirometer during stereotactic radiotherapy for lung tumours

Abstract

The purpose of this study was to evaluate the interbreath-hold reproducibility of the tumour (gross tumour volume, GTV) position and relative reduction of the internal target volume (ITV) using a voluntary breath-hold method with a spirometer in a clinical setting of stereotactic radiotherapy (SRT) for lung tumours 11 patients with 14 lung tumours were enrolled in this study. CT scans were performed once at the free breathing phase and five times at the breath holding phase before the first treatment day. Patients held their breath at the end-expiration phase under spirometer-based monitoring. All GTVs were delineated by a physician and the GTV centroid was calculated automatically. To evaluate the interbreath-hold reproducibility of the tumour position, we measured the distance of three dimensions (craniocaudal, CC; left-right, LR; anteroposterior, AP) and vectors between the GTV centroid and bony landmark. The reproducibility was defined as the average of the differences between the GTV centroid and bony landmark from the second to fifth CT scans with regard to that from the first CT scans. We also evaluated the relative reduction of ITV between the free breathing and breath-holding phase. The interbreath-hold reproducibility of the tumour position was 1.3+/-1.3 mm, 1.4+/-1.8 mm, 2.1+/-1.6 mm and 3.3+/-2.2 mm in CC, LR and AP directions and vectors, respectively. ITV at the breath-holding phase was significantly smaller than that at the free breathing phase (P<0.01). In conclusion, the voluntary breath-hold method with a spirometer is feasible, with relatively good reproducibility of the tumour position for SRT in the clinical setting.

Image-guided radiotherapy and motion management in lung cancer

“…The continuous detection of breathing phase as well as the potential lack of consistent correlation with surrogate monitored motion are not issues, although target position still needs to be verified during breath-hold. 30 increased stability of breath-hold procedures, the Active Breathing Coordinator™ (Elekta AB, Stockholm, Sweden) uses a combination of a valve system shutting off air flow and a visual guidance to the patient. 32 As for free breathing, breath-hold during expiration is more stable than during inspiration, but the choice of whether to use expiration or inspiration breath-hold will depend not only on stability but also on dosimetric concerns.…”

Breath‐holding times in various phases of respiration and effect of respiratory training in lung cancer patients

“…Similarly, DEBH and MVBH times were 16.3 and 19.9 s, respectively. There is paucity of literature documenting the median end expiration BH time as a measure for BH technique for motion management for appropriate comparison . No existing study has evaluated BH time at mid‐ventilation phase.…”

“…Therefore, it is advantageous to treat large volume lung tumours in deep inspiratory phase of BH. End expiration phase has better tumour reproducibility than deep inspiration phase, but it negates the benefit of reduced lung density, obtained with deep inspiration. In tumours with smaller volume compared with those with larger volumes, the volume of normal lung irradiated, by the virtue of similar respiratory motion, is inherently smaller.…”

Impact of Breath-Hold Level on Positional Error in Hepatobiliary Radiotherapy with Breath-Hold Respiratory Control

“…The patient can inhale to reach the defined target zone, then hold the breath while using visual data for reinforcement [12]. The preset breath-hold range of the SDX™ system can improve the reproducibility of the predetermined phase of the breathing cycle [13]. Thus, the use of the SDX™ system has been one of the breath-hold systems integrated into radiotherapy treatment for hepatobiliary cancer.…”