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Patient centring and scan length: how inaccurate practice impacts on radiation dose in CT colonography (CTC)

  • RADIOBIOLOGY AND SAFETY
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Abstract

Objective

The aim of this study was to acknowledge errors in patients positioning in CT colonography (CTC) and their effect in radiation exposure.

Materials and methods

CTC studies of a total of 199 patients coming from two different referral hospitals were retrospectively reviewed. Two parameters have been considered for the analysis: patient position in relation to gantry isocentre and scan length related to the area of interest. CTDI vol and DLP were extracted for each patient. In order to evaluate the estimated effective total dose and the dose to various organs, we used the CT-EXPO® software version 2.2. This software provides estimates of effective dose and doses to the other various organs.

Results

Average value of the patients’ position is found to be below the isocentre for 48 ± 25 mm and 29 ± 27 mm in the prone and supine position. It was observed that the increase in CTDI and DLP values for patients in Group 1, due to the inaccurate positioning, was estimated at about 30% and 20% for prone and supine position, respectively, while in Group 2, a decrease in CTDI and DLP values was estimated at about 16% and 18% for prone and supine position, respectively, due to an average position above isocentre. A dose increase ranging from 4 up to 13% was calculated with increasing the over-scanned region below anal orifice.

Conclusion

Radiographers and radiologists need to be aware of dose variation and noise effects on vertical positioning and over-scanning. More accurate training need to be achieved even so when examination protocol varies from general practice.

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Authors and Affiliations

  1. Department of Diagnostic Radiology, University of Palermo, Policlinico Via del Vespro 127, 90127, Palermo, Italy

    Sergio Salerno, Giuseppe Lo Re, Maria Chiara Terranova & Laura Scopelliti

  2. Dipartimento di Scienze Radiologiche, Oncologiche e Anatomo-Patologiche, “Sapienza” - Università di Roma Diagnostica per Immagini - Ospedale I.C.O.T, Via Franco Faggiana n.1668, 04100, Latina, Italy

    Davide Bellini

  3. Department of Surgical and Medical Sciences and Translational Medicine, School of Medicine and Psychology, “Sapienza” - University of Rome, Sant’Andrea University Hospital, Via di Grottarossa 1035, 00189, Rome, Italy

    Marco Rengo

  4. Dipartimento di Fisica e Chimica, Viale delle Scienze Ed. 17, 90128, Palermo, Italy

    Maurizio Marrale

  5. Department of Surgical and Medical Sciences and Translational Medicine, Sapienza-University of Rome, Sant’Andrea University Hospital, Via di Grottarossa 1035, 00189, Rome, Italy

    Andrea Laghi

Authors
  1. Sergio Salerno
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  2. Giuseppe Lo Re
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  4. Marco Rengo
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  7. Laura Scopelliti
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  8. Andrea Laghi
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Corresponding author

Correspondence to Sergio Salerno.

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The authors declare they have no conflict of interest.

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This article is a retrospective study not implying any modification in patients’ treatment or images protocol and is an analysis of dose data of the CT examinations performed. This article does not contain any studies with animals performed by any of the authors.

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This article does not contain any studies with human participants or animals performed by any of the authors.

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Salerno, S., Lo Re, G., Bellini, D. et al. Patient centring and scan length: how inaccurate practice impacts on radiation dose in CT colonography (CTC). Radiol med 124, 762–767 (2019). https://doi.org/10.1007/s11547-019-01021-z

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  • DOI: https://doi.org/10.1007/s11547-019-01021-z

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