Computed Tomography Organ Dose Determination Using ImPACT Simulation Software: Our Findings In South-West Nigeria
Objectives: The aim of this study was to estimate mean organ dose using the imPACT software, and to determine if dose vary significantly for similar organ among the 7 Computed Tomography (CT) units and to compare and correlate our findings with international studies with similar software.
Methods: Seven CT units denoted as A-G was randomly selected. An imPACT Patient Dosimetry Calculator Software was used to determine organ dose to the head, chest, abdomen and pelvic region from 210 patients' CT parameters retrieved from the CT monitor. Data analysis was done using SPSS 16.0 (SPSS Inc, Chicago, IL, USA).
Results: The mean dose to organs in the head (brain and eye lens) was 27.87±9.58 and 55.27±22.34mGy; chest (lungs, breast, thyroid and heart) was 30.63±8.21, 26.41±6.76, 10.21±7.00 and 29.93±9.65mGy; Abdomen (stomach and liver) was 34±12.8 and 33.05±9.93mGy and Pelvis (bladder and uterus) was 32.44±13.8 and 28.97±7.14mGy respectively. Similar organ show statistically significant difference: for brain (p<0.001), eye lens (p=0.001), lungs (p<0.001), breast (p<0.001), thyroid (p=0.008), heart (p<0.001), stomach (p<0.001), liver (p=0.001), bladder (p<0.001) and uterus (p=0.002) among the 7 CT units. There was no correlation in organ dose for this study and those of Tanzania, Turkey, Japan and Thailand.
Conclusion: Significant differences exist in similar organ doses among the 7 CT units in Lagos indicating that there was lack of harmonization in CT protocols.
1. Eze CU, Abonyi LC, Njoku J, Irurhe NK, Olowu O. Assessment of radiation protection practices among radiographers in Lagos, Nigeria. Niger Med J 2013;54:386–91. [CrossRef]
2. Salami BM, Falebita DE, Fatoba JO, Ajala MO. Integrated Geophysical and Geotechnical Investigation of a Bridge Site - A Case Study of a Swamp/Creek Environment in South East Lagos, Nigeria. Ife Journal of Science 2012;14:75–82.
3. Adejoh T, Nzotta CC. Head computed tomography: Dose output and relationship with anthropotechnical parameters. West Afr J Radiol 2016;23:113–7. [CrossRef]
4. Akpochafor MO, Omojola AD, Soyebi KO, Adeneye SO, Aweda MA, Ajayi HB. Assessment of peak kilovoltage accuracy in ten selected X-ray centers in Lagos metropolis, South-Western Nigeria: A quality control test to determine energy output accuracy of an X-ray generator. J Health Res Rev 2016;3:60–5.
5. United Nations Scientific Committee on the Effects of Atomic Radiation. UNSCEAR 2000 Report to the General Assembly, with scientific annexes. Volume I: sources. Available at: http://www.unscear.org/docs/publications/2000/UNSCEAR_2000_Report_Vol.I.pdf, Accessed Apr 17, 2018.
6. Raman SP, Johnson PT, Deshmukh S, Mahesh M, Grant KL, Fishman EK. CT dose reduction applications: available tools on the latest generation of CT scanners. J Am Coll Radiol 2013;10:37–41. [CrossRef]
7. National Council on Radiation Protection and Measurement. Ionizing Radiation Exposure of the Population of the United States: NCRP REPORT No. 160. Bethesda, MD: NCRP Publication; 2009.
8. International Commission on Radiological Protection Managing Patient Dose in Computed Tomography. ICRP Publication 87. Ann ICRP 2000;30:1–86.
9. Valentin J; International Commission on Radiation Protection. Managing patient dose in multi-detector computed tomography(MDCT). ICRP Publication 102. Ann ICRP 2007;37:1–79.
10. Dauer LT, Hricak H. Addressing the challenge of managing radiation use in medicalimaging: paradigm shifts and strategic priorities. Oncology (Williston Park) 2014;28:243-4, 246.
11. Liang Q. Patient-specific CT dose determination from CT immages using Monte Carlo simulations [dissertation]. USA: University of Wisconsin, Madison; 2013. p. 163.
12. Brink JA, Amis ES Jr. Image Wisely: a campaign to increase awareness about adult radiation protection. Radiology 2010;257:601–2. [CrossRef]
13. Sun Z, Ng KH. Multislice CT angiography in cardiac imaging. Part III: radiation risk and dose reduction. Singapore Med J 2010;51:374–80.
14. Kharita MH, Wali KH. Patient management practice in Computed Tomography with special emphasis to Pediatric Patients. Department of Protection and Safety, Atomic Energy Commission, Syria. DPSAEC Report 906. Damascus: Syria; 2010.
15. Huda W. Medical radiation dosimetry. In: Frush DP, Huda W, editors. RSNA Categorical Course indiagnostic radiology physics: from invisible to visible—the science and practice of x-ray imaging and radiation dose optimization. Chicago, IL: Radiological Society of North America; 2006. p. 29–39.
16. Mettler FA Jr, Huda W, Yoshizumi TT, Mahesh M. Effective doses in radiology and diagnostic nuclear medicine: a catalog. Radiology 2008;248:254–63. [CrossRef]
17. LeHeron, JC. CTDOSE - a computer program to enable the calculation of organ doses and dose indices for CT examinations, Christchurch, New Zealand: Ministry of Health, National Radiation Laboratory, 1993.
18. Imaging Performance Assessment of. CT-Scanners Group. ImPACT CT. Patient Dosimetry Calculator v. 0.99 j. London: ImPACT. Available at: http://www. impactscan.org, Accessed Apr 17, 2018.
19. Kalender WA, Schmidt B, Zankl M, Schmidt M. A PC program for estimating organ dose and effective dose values in computed tomography. Eur Radiol 1999;9:555–62. [CrossRef]
20. National Institute of Radiation Hygiene (NIRH). CT dose calculation software “CT-Dose”. NIRH Publication; 1999.
21. Tack D. Comments on Kalender et al.: a PC program for estimating organ dose and effective dose values in computed tomography. Eur Radiol.2001;11:2641–2. [CrossRef]
22. Stamm G, Nagel HD. CT-expo-a novel program for dose evaluation in CT. Rofo 2002;174:1570–6. [CrossRef]
23. Impactscan.org. ImPACT CT dosimetry tool. Available at: http://www.impactscan.org/, Accessed from April 2003 to February 2009.
24. Baadegaard N, Jensen L. A CT dose calculation software “CTdose”. Denmark: National Board of Health, Aarhus University Hospital; 1999.
25. Brix G, Lechel U, Veit R, Truckenbrodt R, Stamm G, Coppenrath EM, et al. Assessment of a theoretical formalism for dose estimation in CT: an anthropomorphic phantom study. Eur Radiol 2004;14:1275–84. [CrossRef]
26. Deak PD, Smal Y, Kalender WA. Multisection CT protocols: sexand age-specific conversion factors used to determine effective dose from dose-length product. Radiology 2010;257:158– 66. [CrossRef]
27. Damilakis J, Perisinakis K, Tzedakis A, Papadakis AE, Karantanas A. Radiation dose to the conceptus from multidetector CT during early gestation: a method that allows for variations in maternal body size and conceptus position. Radiology 2010;257:483–9. [CrossRef]
28. Tzedakis A, Damilakis J, Perisinakis K, Stratakis J, Gourtsoyiannis N. The effect of z overscanning on patient effective dose from multidetector helical computed tomography examinations. Med Phys 2005;32:1621–9. [CrossRef]
29. Mazonakis M, Tzedakis A, Damilakis J, Gourtsoyiannis N. Thyroid dose from common head and neck CT examinations in children: is there an excess risk for thyroid cancer induction? Eur Radiol 2007;17:1352–7. [CrossRef]
30. Sinclair L, Griglock TM, Mench A, Lamoureux R, Cormack B, Bidari S, et al. Determining Organ Doses from CT with Direct Measurements in Postmortem Subjects: Part 2-Correlations with Patient-specific Parameters. Radiology 2015;277:471–6.
31. Zhang D, Padole A, Li X, Singh S, Khawaja RD, Lira D, et al. In vitro dose measurements in a human cadaver with abdomen/ pelvis CT scans. Med Phys 2014;41:091911. [CrossRef]
32. Jones DG, Shrimpton PC. Survey of CT practice in the UK: Part 3. Normalized organ doses calculated using Monte Carlo techniques. Chilton, NRPB-R250. London: HMSO; 1991.
33. Shrimpton PC, Jones DG, Hillier MC, Wall BF, Le Heron JC, Faulkner K. Survey of CT practice in the UK: Part 2: Dosimetric Aspects, National Radiological. Protection Board, Chilton,NRPB-R249. London: HMSO; 1991.
34. Jones DG and Shrimpton PC. Survey of CT practice in the UK: Part 3. Normalised organ doses calculated using Monte Carlo techniques. Chilton, NRPB-R250. London: HMSO; 1991.
35. Cakmak, E.D., Tuncel, N. and Sindir, B. Assessment of Organ Dose by Direct and Indirect Measurements for a Wide Bore X-Ray Computed Tomography Unit That Used in Radiotherapy. Int J Med Phys Clin Eng Radiat Oncol 2015;4:132–42.
36. Ngaile JE, Msaki PK. Estimation of patient organ doses from CT examinations in Tanzania. J Appl Clin Med Phys 2006;7:80– 94. [CrossRef]
37. Puekpuang R, Suriyapee S, Sanghangthum T, Oonsiri S, Insang. P. Organ andeffective doses from a multidetector computed to- mography in chest examination. J Med Phys Biop 2015; 2:27–29.
38. Kawaguchi A, Matsunaga Y, Matsubara K, Suzuki S. A more accurate method to estimate patient dose during body CT examinations with tube current modulation. European Society of Rediology. ECR 2014. Available at: file:///C:/Users/hp/Downloads/ECR2014_C-0738.pdf, Accessed Apr 17, 2018.