title: Development and validation of a patient-tailored dose regime in myocardial perfusion imaging using CZT-SPECT.
abstract: 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.
authors.affiliation: Department of Nuclear Medicine, Isala Hospital, Zwolle, The Netherlands, jorisvdijk@gmail.com.
authors.forename: J D
authors.initials: JD
authors.lastname: van Dijk
authors.forename: P L
authors.initials: PL
authors.lastname: Jager
authors.forename: M
authors.initials: M
authors.lastname: Mouden
authors.forename: C H
authors.initials: CH
authors.lastname: Slump
authors.forename: J P
authors.initials: JP
authors.lastname: Ottervanger
authors.forename: J
authors.initials: J
authors.lastname: de Boer
authors.forename: A H J
authors.initials: AH
authors.lastname: Oostdijk
authors.forename: J A
authors.initials: JA
authors.lastname: van Dalen
mesh_terms: D049628:Body Size; D002104:Cadmium / Q000528:radiation effects; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008297:Male; D020714:Maximum Tolerated Dose; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D015588:Observer Variation; D009943:Organophosphorus Compounds / Q000008:administration & dosage*; D015609:Organotechnetium Compounds / Q000008:administration & dosage*; D061214:Patient Safety; D011829:Radiation Dosage; D011835:Radiation Protection / Q000379:methods; D019275:Radiopharmaceuticals / Q000008:administration & dosage; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013691:Tellurium / Q000528:radiation effects; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014915:Whole-Body Counting / Q000379:methods; D015032:Zinc / Q000528:radiation effects
chemical_list: C474490:CdZnTe; D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D002104:Cadmium; C078700:technetium tc-99m tetrofosmin; D015032:Zinc; D013691:Tellurium