TITLE:
Assessment of Organ Dose and Effective Dose from Head CT Examination in a Large Hospital in South-Southern Nigeria
AUTHORS:
R. I. Obed, M. E. Ekpo
KEYWORDS:
Computed Tomography Dose Index, Dose Length Product, Organ Doses, Effective Dose, CT-ExPO Software
JOURNAL NAME:
International Journal of Medical Physics, Clinical Engineering and Radiation Oncology,
Vol.7 No.4,
September
28,
2018
ABSTRACT: The magnitude of radiation dose imparted to
patients who underwent Head Computed Tomography examination in a large tertiary
hospital in South-Southern Nigeria has been estimated. CT-ExPO dosimetry
software was used to determine the effective and organ doses to the head region
of 40 adult patients. Scanning parameters were retrieved from the CT monitor
for both contrast-enhanced and non-contrast head CT examinations. The tube
potential ranged from 100 kVp to 120 kVp, while the mAs ranged from 127 mAs to
202 mAs. The mean values of the volume Computed Tomography Dose Index (CTDIvol) and Dose Length Product (DLP) for the
contrast-enhanced Head CT examination were 166.4 ± 39.6 mGy and 3568.6 ± 756.1
mGy·cm, respectively, while for the non-contrast
examination they were 86.6 ± 30.4 mGy and 2102.3 ± 870.3 mGy·cm, respectively. The effective doses were higher for the
contrast-enhanced study than for the non-contrast study by a factor of 1.6. Results
were compared with the European Union reference doses and other published data
and were found to be higher. Doses to the organs which comprise of brain, red bone marrow, thyroid and eye lens were
also estimated. The high variation in the doses in this study may be due to
differences in imaging protocols such as large range of mAs and scan lengths
and also the algorithm of the scanner.