Breathing guidance in radiation oncology and radiology: A systematic review of patient and healthy volunteer studies

Pollock, Sean; Keall, Robyn; Keall, P.

doi:10.1118/1.4928488

Cited by 31 publications

(37 citation statements)

References 120 publications

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“…In conclusion, mechanical ventilation has the advantage over all currently used breathing guidance interventions in radiotherapy that require patients to breathe to audible or visual guidance, 2,5 because it does not require any active participation from or feedback to the patient (they can even fall asleep). It may offer particular advantages with the introduction of MR guidance into radiotherapy and for scanned particle therapy.…”

Section: Discussionmentioning

confidence: 99%

“…Both the rate and depth of spontaneous breathing vary markedly, 1 for a number of complex reasons including anxiety 2 and the fact that as soon as subjects think about breathing, they voluntarily change it. Variations in breathing pattern require management in imaging and radiotherapy planning and delivery, not only for breast cancer but also potentially for all tumours in the thorax and abdomen.…”

Section: Introductionmentioning

confidence: 99%

“…2,5 But, all such techniques depend on how well patients respond to feedback and continue to comply with instructions.…”

Section: Introductionmentioning

confidence: 99%

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Reducing the within-patient variability of breathing for radiotherapy delivery in conscious, unsedated cancer patients using a mechanical ventilator

Parkes¹,

Green²,

Stevens³

et al. 2016

BJR

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Objective:Variability in the breathing pattern of patients with cancer during radiotherapy requires mitigation, including enlargement of the planned treatment field, treatment gating and breathing guidance interventions. Here, we provide the first demonstration of how easy it is to mechanically ventilate patients with breast cancer while fully conscious and without sedation, and we quantify the resulting reduction in the variability of breathing.Methods:15 patients were trained for mechanical ventilation. Breathing was measured and the left breast anteroposterior displacement was measured using an Osiris surface-image mapping system (Qados Ltd, Sandhurst, UK).Results:Mechanical ventilation significantly reduced the within-breath variability of breathing frequency by 85% (p < 0.0001) and that of inflation volume by 29% (p < 0.006) when compared with their spontaneous breathing pattern. During mechanical ventilation, the mean amplitude of the left breast marker displacement was 5 ± 1 mm, the mean variability in its peak inflation position was 0.5 ± 0.1 mm and that in its trough inflation position was 0.4 ± 0.0 mm. Their mean drifts were not significantly different from 0 mm min−1 (peak drift was −0.1 ± 0.2 mm min−1 and trough drift was −0.3 ± 0.2 mm min−1). Patients had a normal resting mean systolic blood pressure (131 ± 5 mmHg) and mean heart rate [75 ± 2 beats per minute (bpm)] before mechanical ventilation. During mechanical ventilation, the mean blood pressure did not change significantly, mean heart rate fell by 2 bpm (p < 0.05) with pre-oxygenation and rose by only 4 bpm (p < 0.05) during pre-oxygenation with hypocapnia. No patients reported discomfort and all 15 patients were always willing to return to the laboratory on multiple occasions to continue the study.Conclusion:This simple technique for regularizing breathing may have important applications in radiotherapy.Advances in knowledge:Variations in the breathing pattern introduce major problems in imaging and radiotherapy planning and delivery and are currently addressed to only a limited extent by asking patients to breathe to auditory or visual guidelines. We provide the first demonstration that a completely different technique, of using a mechanical ventilator to take over the patients' breathing for them, is easy for patients who are conscious and unsedated and reduces the within-patient variability of breathing. This technique has potential advantages in radiotherapy over currently used breathing guidance interventions because it does not require any active participation from or feedback to the patient and is therefore worthy of further clinical evaluation.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Reducing the within-patient variability of breathing for radiotherapy delivery in conscious, unsedated cancer patients using a mechanical ventilator

Parkes¹,

Green²,

Stevens³

et al. 2016

BJR

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“…1,7,8 But, all such techniques depend on how well patients respond to feedback and continue to comply with instructions. Newly emerging techniques involve using multiple, short and deep inspiratory breath-holds with air of approximately 20 s. 1,9–13 There is, however, a simple and practical alternative: to deliver each treatment in a single prolonged breath-hold.…”

Section: Introductionmentioning

confidence: 99%

Safely prolonging single breath-holds to >5 min in patients with cancer; feasibility and applications for radiotherapy

Parkes

Green

Stevens

et al. 2016

BJR

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Objective:Multiple, short and deep inspiratory breath-holds with air of approximately 20 s are now used in radiotherapy to reduce the influence of ventilatory motion and damage to healthy tissue. There may be further clinical advantages in delivering each treatment session in only one single, prolonged breath-hold. We have previously developed techniques enabling healthy subjects to breath-hold for 7 min. Here, we demonstrate their successful application in patients with cancer.Methods:15 patients aged 37–74 years undergoing radiotherapy for breast cancer were trained to breath-hold safely with pre-oxygenation and mechanically induced hypocapnia under simulated radiotherapy treatment conditions.Results:The mean breath-hold duration was 5.3 ± 0.2 min. At breakpoint, all patients were normocapnic and normoxic [mean end-tidal partial pressure of carbon dioxide was 36 ± 1 standard error millimetre of mercury, (mmHg) and mean oxygen saturation was 100 ± 0 standard error %]. None were distressed, nor had gasping, dizziness or disturbed breathing in the post-breath-hold period. Mean blood pressure had risen significantly from 125 ± 3 to 166 ± 4 mmHg at breakpoint (without heart rate falling), but normalized within approximately 20 s of the breakpoint. During breath-holding, the mean linear anteroposterior displacement slope of the L breast marker was <2 mm min−1.Conclusion:Patients with cancer can be trained to breath-hold safely and under simulated radiotherapy treatment conditions for longer than the typical beam-on time of a single fraction. We discuss the important applications of this technique for radiotherapy.Advances in knowledge:We demonstrate for the first time a technique enabling patients with cancer to deliver safely a single prolonged breath-hold of >5 min (10 times longer than currently used in radiotherapy practice), under simulated radiotherapy treatment conditions.

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“…These extreme scenarios are not observed in the patient samples of this study. In clinical practice, if prominent irregularities exist, patients can be assisted with breathing coaching [50] or compression devices to make the breathing pattern more reproducible. A detailed analysis taking breathing irregularities into account will be performed on a larger patient cohort in the future.…”

Section: Discussionmentioning

confidence: 99%

A Biomechanical Modeling Guided CBCT Estimation Technique

You

Tehrani

Wang

2017

IEEE Trans. Med. Imaging

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Two-dimensional-to-three-dimensional (2D-3D) deformation has emerged as a new technique to estimate cone-beam computed tomography (CBCT) images. The technique is based on deforming a prior high-quality 3D CT/CBCT image to form a new CBCT image, guided by limited-view 2D projections. The accuracy of this intensity-based technique, however, is often limited in low-contrast image regions with subtle intensity differences. The solved deformation vector fields (DVFs) can also be biomechanically unrealistic. To address these problems, we have developed a biomechanical modeling guided CBCT estimation technique (Bio-CBCT-est) by combining 2D-3D deformation with finite element analysis (FEA)-based biomechanical modeling of anatomical structures. Specifically, Bio-CBCT-est first extracts the 2D-3D deformation-generated displacement vectors at the high-contrast anatomical structure boundaries. The extracted surface deformation fields are subsequently used as the boundary conditions to drive structure-based FEA to correct and fine-tune the overall deformation fields, especially those at low-contrast regions within the structure. The resulting FEA-corrected deformation fields are then fed back into 2D-3D deformation to form an iterative loop, combining the benefits of intensity-based deformation and biomechanical modeling for CBCT estimation. Using eleven lung cancer patient cases, the accuracy of the Bio-CBCT-est technique has been compared to that of the 2D-3D deformation technique and the traditional CBCT reconstruction techniques. The accuracy was evaluated in the image domain, and also in the DVF domain through clinician-tracked lung landmarks.

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Breathing guidance in radiation oncology and radiology: A systematic review of patient and healthy volunteer studies

Cited by 31 publications

References 120 publications

Reducing the within-patient variability of breathing for radiotherapy delivery in conscious, unsedated cancer patients using a mechanical ventilator

Reducing the within-patient variability of breathing for radiotherapy delivery in conscious, unsedated cancer patients using a mechanical ventilator

Safely prolonging single breath-holds to >5 min in patients with cancer; feasibility and applications for radiotherapy

A Biomechanical Modeling Guided CBCT Estimation Technique

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