Patient Centring and Scan Length: How Inaccurate Practice Impacts on Radiation Dose in CT Colonography (CTC)

Overview

Journal Radiol Med

Specialty Radiology

Date 2019 Mar 9

PMID 30848421

Citations 3

Authors

Sergio Salerno

Giuseppe Lo Re

Davide Bellini

Marco Rengo

Maurizio Marrale

Maria Chiara Terranova

Laura Scopelliti

Andrea Laghi

Affiliations

Soon will be listed here.

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.

Citing Articles

Estimation and comparison of the effective dose and lifetime attributable risk of thyroid cancer between males and females in routine head computed tomography scans: a multicentre study.

Khoramian D, Haghparast M, Honardari A, Nouri E, Ranjbar E, Abedi-Friouzjah R J Med Radiat Sci. 2024; 71(2):240-250.

PMID: 38216155 PMC: 11177018. DOI: 10.1002/jmrs.752.

Large Bowel Ischemia/Infarction: How to Recognize It and Make Differential Diagnosis? A Review.

Iacobellis F, Narese D, Berritto D, Brillantino A, Di Serafino M, Guerrini S Diagnostics (Basel). 2021; 11(6).

PMID: 34070924 PMC: 8230100. DOI: 10.3390/diagnostics11060998.

Editorial from guest editors current Euratom legislation (DE 59/2013): new patient management in radiation protection.

Guglielmi G, Pinto A, Salerno S Radiol Med. 2019; 124(8):711-713.

PMID: 31468300 DOI: 10.1007/s11547-019-01070-4.

References

Nicholson R, Fetherston S . Primary radiation outside the imaged volume of a multislice helical CT scan. Br J Radiol. 2002; 75(894):518-22. DOI: 10.1259/bjr.75.894.750518. View

Toth T, Ge Z, Daly M . The influence of patient centering on CT dose and image noise. Med Phys. 2007; 34(7):3093-101. DOI: 10.1118/1.2748113. View

Brenner D, Hall E . Computed tomography--an increasing source of radiation exposure. N Engl J Med. 2007; 357(22):2277-84. DOI: 10.1056/NEJMra072149. View

. The 2007 Recommendations of the International Commission on Radiological Protection. ICRP publication 103. Ann ICRP. 2007; 37(2-4):1-332. DOI: 10.1016/j.icrp.2007.10.003. View

Levin B, Lieberman D, McFarland B, Smith R, Brooks D, Andrews K . Screening and surveillance for the early detection of colorectal cancer and adenomatous polyps, 2008: a joint guideline from the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology. CA Cancer J Clin. 2008; 58(3):130-60. DOI: 10.3322/CA.2007.0018. View

Graser A, Stieber P, Nagel D, Schafer C, Horst D, Becker C . Comparison of CT colonography, colonoscopy, sigmoidoscopy and faecal occult blood tests for the detection of advanced adenoma in an average risk population. Gut. 2008; 58(2):241-8. DOI: 10.1136/gut.2008.156448. View

Sodickson A, Baeyens P, Andriole K, Prevedello L, Nawfel R, Hanson R . Recurrent CT, cumulative radiation exposure, and associated radiation-induced cancer risks from CT of adults. Radiology. 2009; 251(1):175-84. DOI: 10.1148/radiol.2511081296. View

Regge D, Laudi C, Galatola G, Della Monica P, Bonelli L, Angelelli G . Diagnostic accuracy of computed tomographic colonography for the detection of advanced neoplasia in individuals at increased risk of colorectal cancer. JAMA. 2009; 301(23):2453-61. DOI: 10.1001/jama.2009.832. View

Gudjonsdottir J, Svensson J, Campling S, Brennan P, Jonsdottir B . Efficient use of automatic exposure control systems in computed tomography requires correct patient positioning. Acta Radiol. 2009; 50(9):1035-41. DOI: 10.3109/02841850903147053. View

10.

Tsalafoutas I . The impact of overscan on patient dose with first generation multislice CT scanners. Phys Med. 2010; 27(2):69-74. DOI: 10.1016/j.ejmp.2010.03.001. View

11.

Leng S, Yu L, McCollough C . Radiation dose reduction at CT enterography: How low can we go while preserving diagnostic accuracy?. AJR Am J Roentgenol. 2010; 195(1):76-7. DOI: 10.2214/AJR.10.4676. View

12.

Berrington de Gonzalez A, Kim K, Knudsen A, Lansdorp-Vogelaar I, Rutter C, Smith-Bindman R . Radiation-related cancer risks from CT colonography screening: a risk-benefit analysis. AJR Am J Roentgenol. 2011; 196(4):816-23. PMC: 3470483. DOI: 10.2214/AJR.10.4907. View

13.

Habibzadeh M, Ay M, Asl A, Ghadiri H, Zaidi H . Impact of miscentering on patient dose and image noise in x-ray CT imaging: phantom and clinical studies. Phys Med. 2011; 28(3):191-9. DOI: 10.1016/j.ejmp.2011.06.002. View

14.

Thrall J . Radiation exposure in CT scanning and risk: where are we?. Radiology. 2012; 264(2):325-8. DOI: 10.1148/radiol.12121137. View

15.

Neri E, Halligan S, Hellstrom M, Lefere P, Mang T, Regge D . The second ESGAR consensus statement on CT colonography. Eur Radiol. 2012; 23(3):720-9. PMC: 3563960. DOI: 10.1007/s00330-012-2632-x. View

16.

Kidoh M, Nakaura T, Nakamura S, Oda S, Utsunomiya D, Sakai Y . Low-dose abdominal CT: comparison of low tube voltage with moderate-level iterative reconstruction and standard tube voltage, low tube current with high-level iterative reconstruction. Clin Radiol. 2013; 68(10):1008-15. DOI: 10.1016/j.crad.2013.04.008. View

17.

Del Gaizo A, Fletcher J, Yu L, Paden R, Spencer G, Leng S . Reducing radiation dose in CT enterography. Radiographics. 2013; 33(4):1109-24. DOI: 10.1148/rg.334125074. View

18.

Colagrande S, Origgi D, Zatelli G, Giovagnoni A, Salerno S . CT exposure in adult and paediatric patients: a review of the mechanisms of damage, relative dose and consequent possible risks. Radiol Med. 2014; 119(10):803-10. DOI: 10.1007/s11547-014-0393-0. View

19.

Kaasalainen T, Palmu K, Reijonen V, Kortesniemi M . Effect of patient centering on patient dose and image noise in chest CT. AJR Am J Roentgenol. 2014; 203(1):123-30. DOI: 10.2214/AJR.13.12028. View

20.

Harri P, Moreno C, Nelson R, Fani N, Small W, Duong P . Variability of MDCT dose due to technologist performance: impact of posteroanterior versus anteroposterior localizer image and table height with use of automated tube current modulation. AJR Am J Roentgenol. 2014; 203(2):377-86. DOI: 10.2214/AJR.13.11608. View