Personalized Models for Injected Activity Levels in SPECT Myocardial Perfusion Imaging

Abstract

We propose a patient-specific ("personalized") approach for tailoring the injected activities to individual patients in order to achieve dose reduction in SPECT-myocardial perfusion imaging (MPI). First, we develop a strategy to determine the minimum dose levels required for each patient in a large set of clinical acquisitions (857 subjects) such that the reconstructed images are sufficiently similar to that obtained at conventional clinical dose. We then apply machine learning models to predict the required dose levels on an individual basis based on a set of patient attributes which include body measurements and various clinical variables. We demonstrate the personalized dose models for two commonly used reconstruction methods in clinical SPECT-MPI: 1) conventional filtered backprojection (FBP) with post-filtering, and 2) ordered-subsets expectationmaximization (OS-EM) with corrections for attenuation, scatter and resolution, and evaluate their performance in perfusion-defect detection by using the clinical Quantitative Perfusion SPECT (QPS) software package. The results indicate that the achieved dose reduction can vary greatly among individuals from their conventional clinical dose, and that the personalized dose models can achieve further reduction on average compared to a global (non-patient specific) dose reduction approach. In particular, the average personalized dose level can be reduced to 58% and 54% of the full clinical dose, respectively, for FBP and OS-EM reconstruction, while without deteriorating the accuracy in perfusion-defect detection. Furthermore, with the average

An Algorithm for Individual Dosage in Cadmium–Zinc–Telluride SPECT-Gated Radionuclide Angiography

“…Previous studies have already evaluated the possibility of using personalised models when planning doses for a radionuclide-based assessment of cardiac function. These studies have primarily focused on myocardial perfusion imaging [ 11 , 12 , 13 , 16 , 17 ], but one study has evaluated planar ERNA where the dose was based upon the patient’s physical variables according to a chart and not a formula, which was declared to be a weakness of the method [ 18 ].…”