Motion management within two respiratory-gating windows: feasibility study of dual quasi-breath-hold technique in gated medical procedures

Abstract

A dual quasi-breath-hold (DQBH) technique is proposed for respiratory motion management (a hybrid technique combining breathing-guidance with breath-hold task in the middle). The aim of this study is to test a hypothesis that the DQBH biofeedback system improves both the capability of motion management and delivery efficiency. Fifteen healthy human subjects were recruited for two respiratory motion measurements (free breathing and DQBH biofeedback breathing for 15 min). In this study, the DQBH biofeedback system utilized the abdominal position obtained using an real-time position management (RPM) system (Varian Medical Systems, Palo Alto, USA) to audio-visually guide a human subject for 4 s breath-hold at EOI and 90% EOE (EOE90%) to improve delivery efficiency. We investigated the residual respiratory motion and the delivery efficiency (duty-cycle) of abdominal displacement within the gating window. The improvement of the abdominal motion reproducibility was evaluated in terms of cycle-to-cycle displacement variability, respiratory period and baseline drift. The DQBH biofeedback system improved the abdominal motion management capability compared to that with free breathing. With a phase based gating (mean ± std: 55 ± 5%), the averaged root mean square error (RMSE) of the abdominal displacement in the dual-gating windows decreased from 2.26 mm of free breathing to 1.16 mm of DQBH biofeedback (p-value = 0.007). The averaged RMSE of abdominal displacement over the entire respiratory cycles reduced from 2.23 mm of free breathing to 1.39 mm of DQBH biofeedback breathing in the dual-gating windows (p-value = 0.028). The averaged baseline drift dropped from 0.9 mm min(-1) with free breathing to 0.09 mm min(-1) with DQBH biofeedback (p-value = 0.048). The averaged duty-cycle with an 1 mm width of displacement bound increased from 15% of free breathing to 26% of DQBH biofeedback (p-value = 0.003). The study demonstrated that the DQBH biofeedback system has the potential to significantly reduce the residual respiratory motion with the improved duty cycle during the respiratory gating procedure.

Breath-hold MR-HIFU hyperthermia: phantom and in vivo feasibility

“…We did not evaluate the effect of using end-inspiration versus end-expiration breath holds. In pediatric MR imaging, end-expiration breath holds are more reproducible [33,54,55]; similar conclusions arise from the adult abdominal imaging and respiratory-gated radiotherapy [56,57]. Another limitation of our study is that heating experiments were limited to 10 minutes, which allowed for repeated measurements and assessment of variability, whereas longer durations may be desirable for applications like drug release from temperature-sensitive liposomes [58].…”

Audiovisual biofeedback guided breath-hold improves lung tumor position reproducibility and volume consistency

“…AVBH can be used as a conventional breath-hold technique for a consistent tumor position. In addition, the acquisition of 4-dimensional MRI scans is still a challenge, so AVBH could be used for (1) 2 respiratory-gating windows with a dual quasi-breath-hold technique 8 ; (2) a measure of 4-dimensional tumor motion by using inhalation and exhalation breath-hold data and evaluating tumor motion range as measured with 4-dimensional CT 32 ; and (3) real-time 4-dimensional tumor motion using 3-dimensional breath-hold data as a reference in conjunction with 2-dimensional cine-MRI. 33 …”

“…Breath-hold techniques are frequently used to immobilize respiratory-induced tumor motion, leading to the reduction of respiratory-related motion artifacts in medical imaging and clinically meaningful tumor positions and shapes in respiratory-gated radiation treatment. 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 In addition, the immobilization of lung tumors 1 can reduce phase or time shift between surrogates (ie, abdomen, chest, and diaphragm) and tumors 9 and system latency between tumor positioning and gating. 10 Immobilizing the tumor position is advantageous in reducing treatment margins and treatment delivery time.…”

“… 4 , 5 A quasi-breath-hold using consecutive short breath-holds (3, 5, or 7 seconds) has demonstrated equivalent or less motion variation while improving breath-hold efficiency. 7 , 8 Visual biofeedback techniques have also reduced the uncertainty of target position by improving the reproducibility of abdominal and chest wall and pancreatic tumor positions using voluntary breath-hold techniques. 3 , 7 , 8 , 12 , 13 However, lung tumor position reproducibility and volume consistency using audiovisual guidance for inhalation and exhalation breath-holds for precise lung cancer radiation therapy has not been studied.…”

Direct tumor visual feedback during free breathing in 0.35T MRgRT

“…6,7 Recently, several respiratory monitoring systems 3,[7][8][9][10] were introduced for respiratory motion management in radiotherapy providing respiratory guidance during radiotherapy in addition to medical imaging. 11,12 For instance, audio-visual biofeedback 7 uses a noninvasive external marker to measure abdominal motion and uses audio-visual (AV) tools to return that information to the patient for respiratory motion guidance. Audio-visual biofeedback can reduce average cycle-to-cycle variations in breathing displacement and period by up to 50% and 70%, respectively.…”