Assessment of radiation risks of multiple CT images with the use of modern CT scanners

«Radiation and Risk», 2024, vol. 33, No. 1, pp.13-23

DOI: 10.21870/0131-3878-2024-33-1-13-23

Authors

Kashcheev V.V. – Head of Lab., C. Sc., Biol.
Pryakhin E.A. – Researcher. Contacts: 4 Korolyov str., Obninsk, Kaluga region, Russia, 249035. Tel.: (484) 399-32-81; e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it. .
Menyajlo A.N. – Lead. Researcher, C. Sc., Biol. A. Tsyb MRRC.
A. Tsyb MRRC, Obninsk

Abstract

Technological developments, as well as software upgrades to existing computerized tomography (CT) scanners, require a continuous review of the methods for estimating radiation risk from CT procedures. According to the International Commission on Radiological Protection (ICRP), such assessments should be based on absorbed doses in organs and tissues exposed to radiation. This work is devoted to the study of the influence of various characteristics of the CT (manufacturer, type of scanner, etc.) on the evaluation of radiation risks on the example of multiple exposures in standard CT procedures. As an example, the value of lifetime attribute risk (LAR) and lifetime attributable risk fraction (LARF) for 5 CT scans during the life of a woman aged 20, 25, 30, 45 and 50 years is estimated. The lifetime attributable risk of possible cancer induction was estimated according to the ICRP mathematical model (Publication 103) and using the medical and demographic characteristics of the Russian population, as well as scan protocol data for typical CT scanners of selected models. The results were obtained with the use of old and updated conversion factors for the DLP (Dose Length Product – a measure of the absorbed radiation dose for the whole CT examination) parameter to organ doses from a particular procedure. The lifetime attributable risk of possible cancer induction calculated using organ doses derived from old conversion factors was compared with the risk calculated with data for modern CT scanners with updated conversion factors. The LAR was evaluated over time for one CT examination, two, three, four and five different procedures during the patient's lifetime. It was found that to date such factor as software updates in the field of optimisation of scanning protocols or the CT scanner manufacturer still do not has a significant impact on the radiation risks associated with specific diagnostic procedures. The methods developed by the authors for calculating absorbed doses and radiation risks can be used in planning CT examinations and optimising patient dose loads on any modern CT scanners.

Key words
radiation risk, medical exposure, computed tomography, multiple exposures, DLP, organ dose, dose conversion factors, lifetime attribute risk (LAR), lifetime attributable risk fraction (LARF), simulation modelling, radiobiology, radiology, nuclear medicine and imaging, public health.

References

1. Kashcheev V.V., Pryakhin E.A. Medical diagnostic imaging: radiation safety issues. Review. Radiatsiya i risk – Radiation and Risk, 2018, vol. 27, no. 4, pp. 49-64. (In Russian).

2. Ivanov V.K., Kashcheev V.V., Chekin S.Yu., Menyaylo A.N., Pryakhin E.A., Tsyb A.F., Mettler F.A. Assessment of radiation risk associated with medical exposure in terms of effective and organ doses. Radiatsiya i risk – Radiation and Risk, 2012, vol. 21, no. 4, pp. 7-23. (In Russian).

3. Kashcheev V.V., Pryakhin E.A., Menyaylo A.N., Chekin S.Yu., Ivanov V.K. Calculation of equivalent doses to organs and tissues, as well as lifetime attributable risk from typical computed tomography imaging. Radiatsiya i risk – Radiation and Risk, 2013, vol. 22, no. 3, pp. 8-20. (In Russian).

4. Ivanov V.K., Tsyb A.F., Mettler F.A., Menyaylo A.N., Kashcheev V.V. Methodology for estimating cancer risks of diagnostic medical exposure: with an example of the risks associated with computed tomography. Health Phys., 2012, vol. 103, no. 6, pp. 732-739.

5. Kashcheev V.V., Pryakhin E.A., Menyajlo A.N. Methodology for estimating the radiation risk of medical exposure during computed tomography considering the uncertainties of the risk model. Radiatsiya i risk – Radiation and Risk, 2023, vol. 32, no. 2, pp. 47-55. (In Russian).

6. Ivanov V.K., Kashcheev V.V., Chekin S.Yu., Menyaylo A.N., Pryakhin E.A., Tsyb A.F., Mettler F.A. Estimating personal radiation risks attributed to multiple computed tomography scanning. ANRI, 2014, no. 1, pp. 65-77. (In Russian).

7. Ivanov V.K., Menyailo A.N., Kashcheev V.V., Chekin S.Yu., Gorsky A.I., Maksioutov M.A., Tumanov K.A. Comparative analysis of modern models of radiation risk assessment of the ICRP and UNSCEAR. ANRI, 2011, no. 3(66), pp. 18-29. (In Russian).

8. Ivanov V.K., Tsyb A.F., Mettler F.A., Menyaylo A.N., Kashcheev V.V. Health risks of medical radiation exposure. Radiatsiya i risk – Radiation and Risk, 2011, vol. 22, no. 2, pp. 17-28. (In Russian).

9. ICRP, 2007. The 2007 Recommendations of the International Commission on Radiological Protection. ICRP Publication 103. Ann. ICRP, 2007, vol. 37, no. 2-4, pp. 1-332.

10. Preston D.L., Kusumi S., Tomonaga M., Izumi S., Ron E., Kuramoto A., Kamada N., Dohy H., Matsuo T., Nonaka H., Thompson D.E., Soda M., Mabuchi K. Cancer incidence in atomic bomb survivors. Part III: Leuke-mia, lymphoma and multiple myeloma, 1950-1987. Radiat. Res., 1994, vol. 137, no. 2 (Suppl.), pp. S68-S97.

11. Stamm G., Nagel H.D. CT-expo: a novel program for dose evaluation in CT. Rofo, 2002, vol. 174, no. 12, pp. 1570-1576.

12. The radiation doses to the Russian population in 2016: information collection. St. Petersburg, Ramzaev’s NIIRG Publ., 2017. 125 p. (In Russian).

13. Radiation risk assessment in patients during radiological examinations. Methodical recommendations MR 2.6.1.0098-15. Moscow, Rospotrebnadzor, 2015. (In Russian).

14. Shrimpton P.C., Hillier M.C., Lewis M.A., Dunn M. National survey of doses from CT in the UK: 2003. Br. J. Radiol., 2006, vol. 79, no. 948, pp. 968-980.

15. Kritsaneepaiboon S., Jutiyon A., Krisanachinda A. Cumulative radiation exposure and estimated lifetime cancer risk in multiple-injury adult patients undergoing repeated or multiple CTs. Eur. J. Trauma Emerg. Surg., 2018, vol. 44, no. 1, pp. 19-27.

Full-text article (in Russian)