Lung volume reproducibility under ABC control and self‐sustained breath‐holding

Abstract

An Active Breathing Coordinator (ABC) can be employed to induce breath‐holds during CT imaging and radiotherapy of lung, breast and liver cancer, and recently during lung cancer MRI. The apparatus measures and controls respiratory volume, hence subject lung volume reproducibility is its principal measure of effectiveness. To assess ABC control quality, the intra‐session reproducibility of ABC‐induced lung volumes was evaluated and compared with that reached by applying the clinical standard of operator‐guided self‐sustained breath‐holds on healthy volunteers during MRI. Inter‐session reproducibility was investigated by repeating ABC‐controlled breath‐holds on a second visit. Additionally, lung volume agreement with ABC devices used with different imaging modalities in the same institution (MR, CT), or for a breast trial treatment, was assessed. Lung volumes were derived from three‐dimensional (3D) T1‐weighted MRI datasets by three observers employing semiautomatic lung delineation on a radiotherapy treatment planning system. Inter‐observer variability was less than 6% of the delineated lung volumes. Lung volume agreement between the different conditions over all subjects was investigated using descriptive statistics. The ABC equipment dedicated for MR application exhibited good intra‐session and inter‐session lung volume reproducibility (1.8% and 3% lung volume variability on average, respectively). MR‐assessed lung volumes were similar using different ABC equipment dedicated to MR, CT, or breast radiotherapy. Overall, lung volumes controlled by the same or different ABC devices agreed better than with self‐controlled breath‐holds, as suggested by the average ABC variation of 1.8% of the measured lung volumes (99 mL), compared to the 4.1% (226 mL) variability observed on average with self‐sustained breath‐holding.

Robust quantification of CT‐ventilation biomarker techniques and repeatability in a porcine model

“…Tightly controlling subject breathing patterns (as quantified in Table 2) was advantageous for reducing breathing-related uncertainty. Similar TV variations were seen in a previous study of six human subjects where intraday breath-hold volumes with an active breathing coordinator (ABC) and through self -sustained breathholds had average standard deviations of 99 cc and 226 cc, 40 respectively. Du et al 29 previously demonstrated strong CT-ventilation biomarker reproducibility in anesthetized, mechanically ventilated sheep and reduced reproducibility in free-breathing human subjects.Du also noted that reproducibility was heavily dependent on repeatability of subjects' breathing patterns and respiratory effort.…”

“…Tightly controlling subject breathing patterns (as quantified in Table 2) was advantageous for reducing breathing‐related uncertainty. Similar TV variations were seen in a previous study of six human subjects where intraday breath‐hold volumes with an active breathing coordinator (ABC) and through self‐sustained breath‐holds had average standard deviations of 99 cc and 226 cc, 40 respectively. Du et al 29 .…”

Current status of proton therapy techniques for lung cancer

“…ABC devices assisted BH was more stable than self-controlled BHs. The average lung volume variation with ABC was 1.8% of the measured lung volumes (99 mL) and was smaller than the 4.1% (226 mL) variability obtained with the self-sustained BH [85].…”

Reproducibility of deep inspiration breath hold with active breathing coordinator: a dosimetric assessment of inter-fractional cardiac dose variation in left-sided partial breast radiotherapy

“…Additionally, the ABC device has demonstrated high consistency in controlling lung volumes, highlighting its reliability in delivering reproducible breath-holds. 32 This precision enhances the safety and accuracy of radiation delivery, reinforcing the effectiveness of the ABC device in protecting critical OARs. In contrast, DIBH patient setup based solely on surface guided radiation therapy (SGRT), without complementary imaging guidance, is inherently dependent on patient-specific factors such as setup error, surface irregularities, respiratory behaviour and potential breast deformation.…”