scholarly journals Accuracy of automated patient positioning in CT using a 3D camera for body contour detection

2018 ◽  
Vol 29 (4) ◽  
pp. 2079-2088 ◽  
Author(s):  
Ronald Booij ◽  
Ricardo P.J. Budde ◽  
Marcel L. Dijkshoorn ◽  
Marcel van Straten
2020 ◽  
Vol 31 (1) ◽  
pp. 131-138
Author(s):  
Ronald Booij ◽  
Marcel van Straten ◽  
Andreas Wimmer ◽  
Ricardo P.J. Budde

Abstract Objective To assess the accuracy of a 3D camera for body contour detection in pediatric patient positioning in CT compared with routine manual positioning by radiographers. Methods and materials One hundred and ninety-one patients, with and without fixation aid, which underwent CT of the head, thorax, and/or abdomen on a scanner with manual table height selection and with table height suggestion by a 3D camera were retrospectively included. The ideal table height was defined as the position at which the scanner isocenter coincides with the patient’s isocenter. Table heights suggested by the camera and selected by the radiographer were compared with the ideal height. Results For pediatric patients without fixation aid like a baby cradle or vacuum cushion and positioned by radiographers, the median (interquartile range) absolute table height deviation in mm was 10.2 (16.8) for abdomen, 16.4 (16.6) for head, 4.1 (5.1) for thorax-abdomen, and 9.7 (9.7) for thorax CT scans. The deviation was less for the 3D camera: 3.1 (4.7) for abdomen, 3.9 (6.3) for head, 2.2 (4.3) for thorax-abdomen, and 4.8 (6.7) for thorax CT scans (p < 0.05 for all body parts combined). Conclusion A 3D camera for body contour detection allows for automated and more accurate pediatric patient positioning than manual positioning done by radiographers, resulting in overall significantly smaller deviations from the ideal table height. The 3D camera may be also useful in the positioning of patients with fixation aid; however, evaluation of possible improvements in positioning accuracy was limited by the small sample size. Key Points • A 3D camera for body contour detection allows for automated and accurate pediatric patient positioning in CT. • A 3D camera outperformed radiographers in positioning pediatric patients without a fixation aid in CT. • Positioning of pediatric patients with fixation aid was feasible using the 3D camera, but no definite conclusions were drawn regarding the positioning accuracy due to the small sample size.


Author(s):  
Ronald Booij ◽  
Marcel van Straten ◽  
Andreas Wimmer ◽  
Ricardo P. J. Budde

Abstract Objective To assess the influence of breathing state on the accuracy of a 3D camera for body contour detection and patient positioning in thoracic CT. Materials and methods Patients who underwent CT of the thorax with both an inspiratory and expiratory scan were prospectively included for analysis of differences in the ideal table height at different breathing states. For a subgroup, an ideal table height suggestion based on 3D camera images at both breathing states was available to assess their influence on patient positioning accuracy. Ideal patient positioning was defined as the table height at which the scanner isocenter coincides with the patient’s isocenter. Results The mean (SD) difference of the ideal table height between the inspiratory and the expiratory breathing state among the 64 included patients was 10.6 mm (4.5) (p < 0.05). The mean (SD) positioning accuracy, i.e., absolute deviation from the ideal table height, within the subgroup (n = 43) was 4.6 mm (7.0) for inspiratory scans and 7.1 mm (7.7) for expiratory scans (p < 0.05) when using corresponding 3D camera images. The mean (SD) accuracy was 14.7 mm (7.4) (p < 0.05) when using inspiratory camera images on expiratory scans; vice versa, the accuracy was 3.1 mm (9.5) (p < 0.05). Conclusion A 3D camera allows for accurate and precise patient positioning if the camera image and the subsequent CT scan are acquired in the same breathing state. It is recommended to perform an expiratory planning image when acquiring a thoracic CT scan in both the inspiratory and expiratory breathing state. Key Points • A 3D camera for body contour detection allows for accurate and precise patient positioning if the camera image and the subsequent CT scan are acquired in the same breathing state. • It is recommended to perform an expiratory planning image when acquiring a thoracic CT scan in both the inspiratory and expiratory breathing state.


2021 ◽  
Vol 136 ◽  
pp. 109537
Author(s):  
Bari Dane ◽  
Thomas O’Donnell ◽  
Shu Liu ◽  
Emilio Vega ◽  
Sharon Mohammed ◽  
...  

Author(s):  
Y. Oulhouq ◽  
A. Rrhioua ◽  
D. Bakari ◽  
M. Zerfaoui ◽  
D. Krim

Abstract Introduction: The objective of radiotherapy immobilisation devices is to improve the reproducibility of patient positioning during treatment sessions. The inclusion of these devices in the treatment protocol may increase the skin dose. In practice, these devices are not systematically taken into account in the dose calculation. Material and methods: In this study, the dosimetric effects of the carbon fibre couch iBEAM Evo Extension 415, with and without three different immobilisation devices (a Klarity Breastboard R610-2ECF, a Bionix Butterfly Board and CIVCO Vac-Lok vacuum bag), were calculated and evaluated on the dose calculation for conformal three-dimensional radiation therapy. The measurements were carried out by comparing the measured dose with the one calculated for three different algorithms, FFT convolution, fast superposition and superposition algorithms, which are implemented in Xio treatment planning system (TPS). Results: Dosimetric tolerance levels have been respected for specific dose calculations, which do not include the fibre couch with or without immobilisation devices. Errors of up to 8% in the dose calculation were obtained for the beams passing through the fibre couch and the breast board base support region. Conclusion: According to the significant attenuation differences of the beam by the fibre couch and immobilisation devices, it was concluded that ignoring the device in the dose calculation can change patient’s skin and target doses. The fibre couch and immobilisation device should be included within external body contour to account for the TPS calculation algorithms dose attenuation.


1996 ◽  
Vol 16 (4) ◽  
pp. 218-223
Author(s):  
R. Rohrich ◽  
P. B. Fodor ◽  
J. J. Petry ◽  
P. Vash

Author(s):  
Gregor Volberg

Previous studies often revealed a right-hemisphere specialization for processing the global level of compound visual stimuli. Here we explore whether a similar specialization exists for the detection of intersected contours defined by a chain of local elements. Subjects were presented with arrays of randomly oriented Gabor patches that could contain a global path of collinearly arranged elements in the left or in the right visual hemifield. As expected, the detection accuracy was higher for contours presented to the left visual field/right hemisphere. This difference was absent in two control conditions where the smoothness of the contour was decreased. The results demonstrate that the contour detection, often considered to be driven by lateral coactivation in primary visual cortex, relies on higher-level visual representations that differ between the hemispheres. Furthermore, because contour and non-contour stimuli had the same spatial frequency spectra, the results challenge the view that the right-hemisphere advantage in global processing depends on a specialization for processing low spatial frequencies.


1971 ◽  
Vol 10 (02) ◽  
pp. 122-128
Author(s):  
W. H. Blahd ◽  
M. A. Winston ◽  
G. T. Krishnamurthy ◽  
P. B. Thomas ◽  
E. Weiss

SummaryBecause of its speed, accuracy, and reproducibility, radioisotopic angiocardiography appears to be the method of choice for the diagnosis of pericardial effusion. Technetium-99m sulfide is preferable to 99mTc sodium pertechnetate in these studies for the following reasons: (1) its specific uptake by the liver aids both in patient positioning and in the accuracy of diagnosis; and (2), studies can be repeated within 15—20 minutes should there be equiment or technical error.


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