Impact of chest wall motion caused by respiration in adjuvant radiotherapy for postoperative breast cancer patients

Abstract

To determine the chest wall movement of each patient during deep inspiratory breath hold (DIBH) and expiratory breath hold (EBH) in postoperative breast cancer patients. Postoperative breast cancer patients who underwent CT simulation for 3D radiotherapy treatment planning during December 2012 to November 2013 were included. Before scanning the radio-opaque wire was placed on the surface for breast and chest wall visualization on CT images, then the patient underwent three phases of CT scanning (free breathing, DIBH, and EBH, respectively). The distances of chest wall motion at five reference points were calculated using the treatment planning system. 38 breast cancer patients who underwent surgery were included. Median age was 48.5 (28–85) years. Median BMI was 23.4 (16.6–38.3) kg/m2. Median lung volume was 3160.5 (1830.8–4754.0) cm3. Median Haller index was 2.43 (1.92–3.56). Median chest wall movement was wider in anteroposterior (A–P, 4.2–5.4 mm) than superoinferior (S–I, 2.5–2.6 mm) and mediolateral (M–L, 0.6–1.1 mm) dimension in all five measured points. There was no significant effect of the type of surgery, BMI, lung volume, and the Haller index on the distances of chest wall movement. Additional margins of 7, 5, and 2 mm to the A–P, S–I, and M–L dimension should adequately cover the extreme chest wall movement in 95 % of the patients. This study showed that the maximal movement of the chest wall during DIBH and EBH was greatest in the A–P axis followed by the S–I axis, while the M–L axis was minimally affected by respiration.

MUSIC Algorithm for Respiratory Rate Estimation Using RF Signals

“…The displacement of the chest wall along the anteroposterior dimension is approximately 4.2 mm ~ 5.4 mm at the normal breathing and 12.6 mm at the deep breathing [27], [31]. The chest wall expands outwards when the air is inhaled and contracts inwards when the air is exhaled, as expected.…”

“…The nominal distance between the transmitter and the receiver is defined as d o and it is expected that the periodic displacement of chest wall changes the traveled distance of the reflected signal as periodically [30], (1) where d(t) is the time-varying distance which is traveled by the signal during the respiratory. Since it is assumed that the displacement of the chest wall is a sinusoidal function of time [31], this distance also varies periodically with the same frequency as the respiratory rate, (2) where ƒ R represents the respiratory rate, ΔA is the maximum displacement of the chest wall. The propagation delay according to the traveled distance is defined as follows,…”

Influence of respiratory movement during regional nodal irradiation after mastectomy for breast cancer: an experimental study

“…Although the respiratory movement of CW in the anterior-posterior direction was the largest among the three directions in general, the movement only ranged from 4.2. to 5.4 mm at all points (18). Thus, we expected that the R05 condition would be generally achievable by patients and that VMAT could be implemented with sufficient accuracy.…”

LungTrack

“…4. The chest displacement during respiration is around 0.5 cm [32]. Although small, this subtle displacement induces a significant amount of phase changes at the reflected signal.…”

“…The heatmap in Fig. 7 shows that when the target is facing the LoS (i.e., 0 • ), we achieve the best sensing performance because the front chest makes the largest movements during respiration [32]. The worst orientation for sensing was when the target's face direction was parallel to the LoS (i.e., 90 • and 270 • ) because the side-to-side shoulder movements during respiration is minimal and thus, difficult to be captured.…”