Affiliations: Department of Biophysics, Faculty of Science, Cairo
University, Cairo, Egypt | Nuclear Cardiology Department, Intensive Care Unit,
Faculty of Medicine, Cairo University Hospitals, Cairo, Egypt
Note: [] Corresponding author: Reem H. El-Gebaly, Department of
Biophysics, Faculty of Science, Cairo University, Cairo, Egypt. E-mail: R_elgebaly@msn.com
Abstract: BACKGROUND: Myocardial perfusion imaging (MPI) can provide the
valuable cardiac functions.Image quality in nuclear medicine tomography is
critically dependent on the activity administered into patients. OBJECTIVE: This study was designed to evaluate the optimum injected dose of
99mTc-MIBI for quantitative assessment of image quality as compared with
standard injected dose used for that purpose. METHODS: The image quality parameters (Contrast, relative noise and contrast to noise ratio)
were determined in 32 patients (21 male, 11 female, age 45–60 y) with weight
60 ± 15 kg. Patients were classified into four groups; each one consisted
of 8 patients. The first group received 370 MBq, the second one received
555 MBq, the third group received 740 MBq and the last group received 925 MBq. RESULTS: Qualitative assessments of the images revealed
equivalent scintigraphic patterns in all patients. There was a significant
difference in the image contrast. The image contrast in the 370 MBq group was
greater than other groups. The image noise between the four groups was
significantly different. It increased with injected dose reduction. Contrast to
noise ratio (CNR) was significantly different between 370 MBq and other groups. CONCLUSION: It is concluded that results from the first group
which received 370 MBq are sufficiently similar to those of the fourth group
(standard group) which received 925 MBq. Consequently,accurate estimations of
differential cardiac functions are possible with the 370 MBq dose.
