Patient-specific SPECT imaging protocols to standardize image noise

  • Sarah G. Cuddy-WalshEmail author
  • Duncan C. Clackdoyle
  • Jennifer M. Renaud
  • R. Glenn Wells
Original Article



In addition to acquired photon counts, image noise depends on the image reconstruction algorithm. This work develops patient-specific activity or acquisition time protocols to standardize the average noise in a reconstructed image for different patients, cameras, and reconstruction algorithms.


Image noise was calculated for images from 43 patients acquired on both a conventional and a multiple-pinhole cardiac SPECT camera. Functions were found to relate image noise to radiotracer activity, scan time, and body mass and were validated by normalizing the image noise in a test set of 58 patients.


There was a 3.6-fold difference in photon sensitivity between the two cameras but a 16-fold difference in activity-scan time was necessary to match the noise levels. Image noise doubled from 45 to 128 kg for the conventional camera (12.8 minutes) and tripled for the multiple-pinhole camera (5 minutes) for 350 MBq (9.5 mCi) 99mTc-tetrofosmin. It was 16.3% and 6.1% respectively for an average sized patient.


A linear scaling of activity with respect to the patient weight normalizes image noise but the scaling factors depend on the choice of camera and image reconstruction parameters. Therefore, equivalent numbers of acquired photon counts are not sufficient to guarantee equivalent image noise.


SPECT myocardial perfusion imaging activity image noise patient-centered imaging 



Attenuation corrected


Decay-corrected activity-scan time protocol


GE discovery NM530c SPECT camera


Maximum a posteriori expectation maximization


Myocardial perfusion imaging


Non-attenuation corrected


Ordered-subset expectation maximization


One-step-late Green’s prior




Single photon emission computed tomography



J. M. Renaud is a consultant for Jubliant DraxImage Inc. and receives royalties for software sales from FlowQuant and Invia Medical Imaging Solutions. R. G. Wells receives research support and honoraria from GE Healthcare for speaking at meetings. S. G. Cuddy-Walsh and D. C. Clackdoyle have nothing to disclose.

Supplementary material

12350_2019_1664_MOESM1_ESM.pdf (192 kb)
Supplementary material 1 (PDF 192 kb)
12350_2019_1664_MOESM2_ESM.pptx (629 kb)
Supplementary material 2 (PPTX 628 kb)


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Copyright information

© American Society of Nuclear Cardiology 2019
corrected publication 2019

Authors and Affiliations

  • Sarah G. Cuddy-Walsh
    • 1
    • 2
    Email author
  • Duncan C. Clackdoyle
    • 2
  • Jennifer M. Renaud
    • 2
  • R. Glenn Wells
    • 1
    • 2
  1. 1.Department of PhysicsCarleton UniversityOttawaCanada
  2. 2.Division of Cardiology, Cardiac ImagingUniversity of Ottawa Heart InstituteOttawaCanada

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