Title:Assessment Relation of Myocardial Detector Counts and Administered Activity
of 99mTc-SestaMIBI in MPI: The Effects of Body Weight, BMI, and
Gender
Volume: 15
Issue: 2
Author(s): Mahdi Mazinani, Mohammad Ali Tajik-Mansoury*, Mahsa Sabour, Majid Jadidi, Milad Peer- Firozjaei and Nader Asadian
Affiliation:
- Department of Medical Physics, Semnan University of Medical Sciences, Semnan, Iran
- Raaheaseman Center of Nuclear
Medicine, Semnan University of Medical Science, Semnan, Iran
Keywords:
Myocardial perfusion imaging, SPECT, radiopharmaceutical activity, 99mTc-Sestamibi, coronary artery disease, body weight.
Abstract:
Introduction: In myocardial perfusion imaging, reducing the number of photons in images
of obese patients causes poor image quality. To solve this problem, we need to inject the tracer
according to the patients' weight. Therefore, this study aimed to investigate the relationship between
myocardial photon counts with patients' weight, BMI, and gender.
Materials and Methods: A total of 129 patients underwent myocardial perfusion imaging in a twoday
stress-first protocol, but only rest images were included in this study. Multiplication factor 
was used to determine the amount of
radiopharmaceutical activity injected into the patients. For evaluating the effect of gender, the photon
counts of 22 female patients were also assessed when the breast tissue was pulled upward
(Breast Up). The total myocardial detector counts in the raw images were calculated from the summation
of 32 projections. A multiple linear regression test was used to simultaneously examine the
effects of weight, BMI, and gender on photon counts.
Results: There was no significant relationship between photon counts and patients' weight
(p=0.129) and BMI (0.406), but gender had significant effects on photon counts, and myocardial
detector counts were found to be higher in males (p=0.00). There was a statistically significant difference
between the images of Breast Up and Non-Breast Up, and myocardial detector counts were
higher in the Breast Up imaging method (p=0.00).
Conclusion: Using the bodyweight formula, the image quality was comparable in obese and lean
patients, but myocardial detector counts were lower in females, and this formula needs to be adjusted
according to the patient's gender.
