Development and validation of a patient-tailored dose regime in myocardial perfusion imaging using CZT-SPECT

J Nucl Cardiol. 2014 Dec;21(6):1158-67. doi: 10.1007/s12350-014-9942-0. Epub 2014 Jul 9.


Background: Guidelines for SPECT myocardial perfusion imaging (MPI) traditionally recommend a fixed tracer dose. Yet, clinical practice shows degraded image quality in heavier patients. The aim was to optimize and validate the tracer dose and scan time to obtain a constant image quality less dependent on patients' physical characteristics.

Methods: 125 patients underwent Cadmium Zinc Telluride (CZT)-SPECT stress MPI using a fixed Tc-99m-tetrofosmin tracer dose. Image quality was scored by three physicians on a 4-point grading scale and related to the number of photon counts normalized to tracer dose and scan time. Counts were correlated with various patient-specific parameters dealing with patient size and weight to find the best predicting parameter. From these data, a formula to provide constant image quality was derived, and subsequently tested in 92 new patients.

Results: Degradation in image quality and photon counts was observed for heavier patients for all patients' specific parameters (P < .01). We found body weight to be the best-predicting parameter for image quality and derived a new dose formula. After applying this new body weight-depended tracer dose and scan time in a new group, image quality was found to be constant (P > .19) in all patients.

Conclusions: Also in CZT SPECT image quality decreases with weight. The use of a tracer dose and scan time that depends linearly on patient's body weight corrected for the varying image quality in CZT-SPECT MPI. This leads to better radiation exposure justification.

Publication types

  • Randomized Controlled Trial
  • Validation Study

MeSH terms

  • Body Size*
  • Cadmium / radiation effects
  • Female
  • Humans
  • Image Interpretation, Computer-Assisted / methods
  • Male
  • Maximum Tolerated Dose*
  • Middle Aged
  • Myocardial Perfusion Imaging / methods*
  • Observer Variation
  • Organophosphorus Compounds / administration & dosage*
  • Organotechnetium Compounds / administration & dosage*
  • Patient Safety
  • Radiation Dosage
  • Radiation Protection / methods
  • Radiopharmaceuticals / administration & dosage
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Tellurium / radiation effects
  • Tomography, Emission-Computed, Single-Photon / methods*
  • Whole-Body Counting / methods
  • Zinc / radiation effects


  • CdZnTe
  • Organophosphorus Compounds
  • Organotechnetium Compounds
  • Radiopharmaceuticals
  • Cadmium
  • technetium tc-99m tetrofosmin
  • Zinc
  • Tellurium