Radiation dose reduction, improved isocenter accuracy and CT scan time savings with automatic patient positioning by a 3D camera

Dane, Bari; O’Donnell, Thomas; Liu, Shu; Vega, Emilio; Mohammed, Sharon; Singh, V. P.; Kapoor, Ankur; Megibow, Alec J.

doi:10.1016/j.ejrad.2021.109537

Cited by 20 publications

(22 citation statements)

References 12 publications

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“…Improved positioning accuracy could also be achieved through the installation of automated patient positioning tools, such as 3D cameras. 25 However, in the absence of these key interventions, the authors recommend acquisition using a 0° localiser to reduce any increase in the total organ doses resultant from patient off‐centring. This recommendation is based on previous retrospective studies, reporting a trend to misposition patients below the gantry iso‐centre and the current experimental findings.…”

Section: Discussionmentioning

confidence: 99%

0° vs. 180° CT localiser: The effect of vertical off‐centring, phantom positioning and tube voltage on dose optimisation in multidetector computed tomography

Al-Hayek

Zheng

Davidson

et al. 2021

J of Medical Radiation Sci

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Introduction: Patient positioning is an essential consideration for the optimisation of radiation dose during CT examinations. The study objectives seek to explore the effects of vertical off-centring, localiser direction (0°and 180°), and phantom positioning (supine and prone) on radiation dose, using three different tube voltages in multidetector computed tomography (MDCT) imaging. Methods: The trunk of a PBU-60 anthropomorphic phantom was imaged using a Discovery CT750 HD -128 slice (GE Healthcare). Images employing 0°and 180°localisers were acquired in supine and prone orientation for each combination of vertical off-centring (AE100, AE60 and AE30 mm) and different tube voltages (80, 120 and 140 kVp), using the system's automatic tube current modulation (ATCM) function. The displayed volume CT dose index (CTDI vol ) and dose length product (DLP) were recorded. Results: With incremental table off-centring of AE100 mm, the dose at 120 kVp in the supine position ranged from 63% to 196% (0°localiser) and from 66% to 191% (180°l ocaliser) as compared to iso-centre. While in the prone position, the dose ranged from 62% to 195% (0°localiser); and 62% to 193% (180°localiser), with a notable dose increase at higher tube voltages. Dose variation and vertical off-centring showed a significant relationship for both 0°and 180°localisers (r = 0.94 and 0.96, respectively, P < 0.001). The CTDI vol variation between supine and prone phantom positions at AE100 mm off-centring was 0.22 mGy (2.9%), and 0.19 mGy (2.3%) when the 0°and 180 °localisers were utilised, respectively. Conclusions: Phantom off-centring and localiser direction evidenced large dose variation. It is recommended that the 0°localiser is employed during CT examinations, in order to minimise the potential additional radiation dose which may result from off-centring and the use of lower tube voltages where clinically appropriate.

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Section: Discussionmentioning

confidence: 99%

0° vs. 180° CT localiser: The effect of vertical off‐centring, phantom positioning and tube voltage on dose optimisation in multidetector computed tomography

Al-Hayek

Zheng

Davidson

et al. 2021

J of Medical Radiation Sci

View full text Add to dashboard Cite

show abstract

“…The effect of improper patient positioning on radiation dose and image quality was not investigated in this paper, since the influence of off-centering patients in a CT scanner on IQ and radiation dose has been extensively described in several publications [2,12,13] and one also on dose saving with the aid of a 3D camera equivalent to the one described in this study [14]. For instance, Monte Carlo simulations in a phantom study resulted in relative organ dose differences of the lungs and heart between 5 and 12% when a patient was positioned 10-20 mm off-center [3].…”

Section: Discussionmentioning

confidence: 99%

Influence of breathing state on the accuracy of automated patient positioning in thoracic CT using a 3D camera for body contour detection

et al. 2021

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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.

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“…Use of camera-assisted patient positioning/isocentre for CT scanning 15 , determining scan range 16 , and virtual MRI cockpits could mean that for high volume low-complexity or routine imaging with patients who have previously undergone imaging that the entire episode of care could be delivered remotely/autonomously in the not-too-distant future. Further examples of AI contribution to practice include the automation of image post processing and dose optimisation 17 .…”

Section: Radiography Practice Applicationsmentioning

confidence: 99%

Artificial intelligence in radiography: Where are we now and what does the future hold?

Malamateniou¹,

Knapp²,

Pergola³

et al. 2021

Radiography

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Radiation dose reduction, improved isocenter accuracy and CT scan time savings with automatic patient positioning by a 3D camera

Cited by 20 publications

References 12 publications

0° vs. 180° CT localiser: The effect of vertical off‐centring, phantom positioning and tube voltage on dose optimisation in multidetector computed tomography

0° vs. 180° CT localiser: The effect of vertical off‐centring, phantom positioning and tube voltage on dose optimisation in multidetector computed tomography

Influence of breathing state on the accuracy of automated patient positioning in thoracic CT using a 3D camera for body contour detection

Artificial intelligence in radiography: Where are we now and what does the future hold?

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