An international journal published by K. N. Toosi University of Technology

Document Type : Research Article

Authors

1 Faculty of Nuclear Engineering and Physics‎, ‎Amirkabir University of Technology‎, ‎Tehran‎, ‎Iran‎.

2 Department of Radiotherapy‎, ‎Chamran Hospital‎, ‎P.O‎. ‎Box 1693715814‎, ‎Tehran‎, ‎Iran

3 Nuclear Science and Technology Research Institute‎, ‎Tehran‎, ‎Iran

Abstract

‎By the rapid development of imaging systems such as PET/CT for diagnosis of cancer‎, ‎the protection of staff and public has become a main health concern‎. ‎Due to serious and irreversible harms of ionization radiations‎, ‎protection of all those who are exposed is the main concern of health issues‎. ‎The main basis of the calculation of the shielding design in the medical imaging systems is that the absorbed dose should not exceed the allowed limit‎. ‎In this study‎, ‎the current shielding status of the PET/CT installations in Tehran's Shariati hospital was investigated using the MCNPX Monte Carlo code to ensure that the dose limits for both the controlled and uncontrolled area are not violated‎. ‎The proposed simulation method was benchmarked with a validated analytical method‎. ‎Shariati hospital provides services to four patients every day‎, ‎leading to a dose rate in the range of 2.6 × 10-6 to 9.35 × 10-3 mSv/week‎. ‎The minimum dose rate in this range represents the value behind the door of the waiting room (public uncontrolled area)‎, ‎while the maximum in this range corresponds to the value behind the glass of the scanner room (operator controlled area)‎. ‎The simulation results for 8 patients/day in this center showed that the dose rate behind the wall of the injection room will increase from 4.88 ×10-6 mSv/week to 2.81 × 10-2 mSv/week‎, ‎which is well below the recommended levels‎. ‎This indicates that the present shielding is adequate for up to four more patients per day‎.

Highlights

  • Calculation of a present PET/CT installation shielding using simulation and analytical method‎.
  • ‎ Comparison of Monte Carlo with analytical method of above PET/CT shielding requirement‎.
  • ‎ Showing that present shielding structure is adequate for treating up to four more patients a day‎.

Keywords

Archer, B. R., Thornby, J., and Bushong, S. C. (1983). Diagnostic X-ray shielding design based on an empirical model of photon attenuation. Health physics, 44(5):507–517.

Bresnahan, M. E. and Shrestha, B. (2012). Potential shielding for a positron emission tomography (PET) suite. Journal of Biomedical Graphics and Computing, 2(1):89.

Coker, A. L. (2007). PET/CT shielding design comparisons. PhD thesis, Texas A&M University.

ICRP (1971). Committee 3 Task Group, P. Grande and MC ORiordan, chairman,Data for Against Ionizing Radiation from External Sources: Supplement to ICRP Publication 15, ICRP-21, International Commission on Radiological Protection.

Johnson, T. E. and Birky, B. K. (2012). Health physics and radiological health. Lippincott Williams & Wilkins.

Madsen, M. T., Anderson, J. A., Halama, J. R., et al. (2006). AAPM task group 108: PET and PET/CT shielding requirements. Medical Physics, 33(1):4–15.

Mawlawi, O., Pan, T., and Macapinlac, H. A. (2006). PET/CT imaging techniques, considerations, and artifacts. Journal of Thoracic Imaging, 21(2):99–110.

Pelowitz, D. B. et al. (2005). MCNPXTM user’s manual. Los Alamos National Laboratory, Los Alamos.

Powsner, R. A. and Powsner, E. R. (2008). Essential nuclear medicine physics. John Wiley & Sons.

Shamsaei Zafarghandi, M. et al. (2014). Study the shielding for PET/CT imaging installations of Shariati hospital of Tehran with Monte Carlo code. Iranian Journal of Radiation Safety and Measurement, 2(2):13–20.