Technical evaluation of different respiratory monitoring systems used for 4D CT acquisition under free breathing

Heinz, C.; Reiner, M. J.; Belka, Claus; Walter, Franziska; Söhn, Matthias

doi:10.1120/jacmp.v16i2.4917

Cited by 21 publications

(33 citation statements)

References 10 publications

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“…De Groote17 proposed a model showing that if there exists asynchrony between motions along the dorsoventral and lateral directions with respiration, there will be a phase shift between the anterior–posterior movement (as measured as the RPM signal) and the change in abdominal perimeter (as measured as the ANZAI belt signal). In addition, in previous studies comparing different external surrogates,13, 16, 18 shape distortion can be observed between the respiratory traces in patients, which has not been investigated in those studies.…”

Section: Introductionmentioning

confidence: 93%

“…Several respiratory monitoring systems using external surrogates are available in the market for the purposes of measuring respiratory motion for 4D CT imaging and gated treatment 5. These systems measure the respiratory motion as the surface movement of abdomen or chest wall (eg, Real‐Time Position Management [RPM],4 C‐RAD,13 GateCT14), or the pressure change in a belt wrapped around the abdomen (eg, ANZAI,15 Bellows16), etc. There is no consensus of which is the best external surrogate with respect to the correlation with the internal tumor motion.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of the combined use of two different respiratory monitoring systems for 4D CT simulation and gated treatment

Liu

Lin

Fan

et al. 2018

J Applied Clin Med Phys

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PurposeTwo different respiratory monitoring systems (Varian's Real‐Time Position Management (RPM) System and Siemens’ ANZAI belt Respiratory Gating System) are compared in the context of respiratory signals and 4D CT images that are accordingly reconstructed. This study aims to evaluate the feasibility of combined use of RPM and ANZAI systems for 4DCT simulation and gated radiotherapy treatment, respectively.MethodsThe RPM infrared reflecting marker and the ANZAI belt pressure sensor were both placed on the patient's abdomen during 4DCT scans. The respiratory signal collected by the two systems was synchronized. Fifteen patients were enrolled for respiratory signal collection and analysis. The discrepancies between the RPM and ANZAI traces can be characterized by phase shift and shape distortion. To reveal the impact of the changes in respiratory signals on 4D images, two sets of 4D images based on the same patient's raw data were reconstructed using the RPM and ANZAI data for phase sorting, respectively. The volume of whole lung and the position of diaphragm apex were measured and compared for each respiratory phase.ResultsThe mean phase shift was measured as 0.2 ± 0.1 s averaged over 15 patients. The shape of the breathing trace was found to be in disagreement. For all the patients, the ANZAI trace had a steeper falloff in exhalation than RPM. The inhalation curve, however, was matched for nine patients, steeper in ANZAI for five patients and steeper in RPM for one patient. For 4D image comparison, the difference in whole‐lung volume was about −4% to +4% and the difference in diaphragm position was about −5 mm to +4 mm, compared in each individual phase and averaged over seven patients.ConclusionsCombined use of one system for 4D CT simulation and the other for gated treatment should be avoided as the resultant gating window would not fully match with each other due to the remarkable discrepancy in breathing traces acquired by the two different surrogate systems.

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Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Evaluation of the combined use of two different respiratory monitoring systems for 4D CT simulation and gated treatment

Liu

Lin

Fan

et al. 2018

J Applied Clin Med Phys

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“…However, both techniques use ionizing radiation which should be reduced to a minimum according to the ALARA-principles [2]. Moreover these techniques lack the ability to sufficiently monitor intrafractional movements of the target caused by respiratory, cardiac or gastrointestinal motion [3]. …”

Section: Introductionmentioning

confidence: 99%

Evaluation of daily patient positioning for radiotherapy with a commercial 3D surface-imaging system (Catalyst™)

et al. 2016

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BackgroundTo report our initial clinical experience with the novel surface imaging system Catalyst™ (C-RAD AB, Sweden) in connection with an Elekta Synergy linear accelerator for daily patient positioning in patients undergoing radiation therapy.MethodsWe retrospectively analyzed the patient positioning of 154 fractions in 25 patients applied to thoracic, abdominal, and pelvic body regions. Patients were routinely positioned based on skin marks, shifted to the calculated isocenter position and treated after correction via cone beam CT which served as gold standard. Prior to CBCT an additional surface scan by the Catalyst™ system was performed and compared to a reference surface image cropped from the planning CT to obtain shift vectors for an optimal surface match. These shift vectors were subtracted from the vectors obtained by CBCT correction to assess the theoretical setup error that would have occurred if the patients had been positioned using solely the Catalyst™ system. The mean theoretical set up-error and its standard deviation were calculated for all measured fractions and the results were compared to patient positioning based on skin marks only.ResultsIntegration of the surface scan into the clinical workflow did not result in a significant time delay. Regarding the entire group, the mean setup error by using skin marks only was 0.0 ± 2.1 mm in lateral, −0.4 ± 2.4 mm in longitudinal, and 1.1 ± 2.6 mm vertical direction. The mean theoretical setup error that would have occurred using solely the Catalyst™ was −0.1 ± 2.1 mm laterally, −1.8 ± 5.4 mm longitudinally, and 1.4 ± 3.2 mm vertically. No significant difference was found in any direction. For thoracic targets the mean setup error based on the Catalyst™ was 0.6 ± 2.6 mm laterally, −5.0 ± 7.9 mm longitudinally, and 0.5 ± 3.2 mm vertically. For abdominal targets, the mean setup error was 0.3 ± 2.2 mm laterally, 2.6 ± 1.8 mm longitudinally, and 2.1 ± 5.5 mm vertically. For pelvic targets, the setup error was −0.9 ± 1.5 mm laterally, −1.7 ± 2.8 mm longitudinally, and 1.6 ± 2.2 mm vertically. A significant difference between Catalyst™ and skin mark based positioning was only observed in longitudinal direction of pelvic targets.ConclusionOptical surface scanning using Catalyst™ seems potentially useful for daily positioning at least to complement usual imaging modalities in most patients with acceptable accuracy, although a significant improvement compared to skin mark based positioning could not be derived from the evaluated data. However, this effect seemed to be rather caused by the unexpected high accuracy of skin mark based positioning than by inaccuracy using the Catalyst™. Further on, surface registration in longitudinal axis seemed less reliable especially in pelvic localization. Therefore further prospective evaluation based on strictly predefined protocols is needed to determine the optimal scanning approaches and parameters.

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“…A median of 93% duty cycle was observed for 5 mm threshold band and a median of 52% for 2 mm. Since no smoothing filters were applied when collecting the Anzai data (raw data) and the system, like many, is known to have an inherent noise component [20,21], we believe that the duty cycle for the 2 mm and 5 mm threshold band could be slightly higher than reported here. Example of the noise peaks are denoted in (Fig.…”

Section: Discussionmentioning

confidence: 81%

High frequency percussive ventilation for respiratory immobilization in radiotherapy

Sala

Nair

Maurer

et al. 2019

Technical Innovations & Patient Support in Radiation Oncolo

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High frequency percussive ventilation (HFPV) employs high frequency low tidal volumes (100-400 bursts/min) to provide respiration in awake patients while simultaneously reducing respiratory motion. The purpose of this study is to evaluate HFPV as a technique for respiratory motion immobilization in radiotherapy. In this study fifteen healthy volunteers (age 30-75 y) underwent HFPV using three different oral interfaces. We evaluated each HFPV oral interface device for compliance, ease of use, comfort, geometric interference, minimal chest wall motion, duty cycle and prolonged percussive time. Their chest wall motion was monitored using an external respiratory motion laser system. The percussive ventilations were delivered via an air driven pneumatic system. All volunteers were monitored for PO 2 and tc-CO 2 with a pulse oximeter and CO 2 Monitoring System. A total of N = 62 percussive sessions were analyzed from the external respiratory motion laser system. Chest-wall motion was well tolerated and drastically reduced using HFPV in each volunteer evaluated. As a result, we believe HFPV may provide thoracic immobilization during radiotherapy, particularly for SBRT and pencil beam scanning proton therapy.

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Technical evaluation of different respiratory monitoring systems used for 4D CT acquisition under free breathing

Cited by 21 publications

References 10 publications

Evaluation of the combined use of two different respiratory monitoring systems for 4D CT simulation and gated treatment

Evaluation of the combined use of two different respiratory monitoring systems for 4D CT simulation and gated treatment

Evaluation of daily patient positioning for radiotherapy with a commercial 3D surface-imaging system (Catalyst™)

High frequency percussive ventilation for respiratory immobilization in radiotherapy

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