Prompt-gamma compensation in Rb-82 myocardial perfusion 3D PET/CT: Effect on clinical practice

Coronary vasomotor dysfunction in cancer survivors treated with thoracic irradiation

BACKGROUND

We sought to test the hypothesis that thoracic radiation therapy (RT) is associated with impaired myocardial flow reserve (MFR), a measure of coronary vasomotor dysfunction.

METHODS

We retrospectively studied thirty-five consecutive patients (71% female, mean ± standard deviation (SD) age: 66 ± 11 years) referred clinically for positron emission tomography/computed tomography (PET/CT) myocardial perfusion imaging at a median (interquartile range, IQR) interval of 4.3 (2.1, 9.7) years following RT for a variety of malignancies. Radiation dose-volume histograms were generated for the heart and coronary arteries for each patient.

RESULTS

The median (IQR) of mean cardiac radiation doses was 12.0 (1.2, 24.2) Gray. There were significant inverse correlations between mean radiation dose and global MFR (MFRGlobal) and MFR in the left anterior descending artery territory (MFRLAD): Pearson's correlation coefficient = - .37 (P = .03) and - .38 (P = .03), respectively. For every one Gray increase in mean cardiac radiation dose, there was a mean ± standard error decrease of .02 ± .01 in MFRGlobal (P = .04) and MFRLAD (P = .03) after adjustment.

CONCLUSIONS

In patients with a history of RT clinically referred for cardiac stress PET, we found an inverse correlation between mean cardiac radiation dose and coronary vasomotor function.

Improved Quantification of 18F-FDG PET during 131I-Rituximab Therapy on Mouse Lymphoma Models after 131I Prompt Emission Correction

¹⁸F-FDG Positron Emission Tomography (PET) is used to monitor tumor response to ¹³¹I-therapy, but is confounded by prompt emissions (284, 364, 637, and 723 keV) from ¹³¹I, particularly in animal PET imaging. We propose a method for correcting this emission in ¹⁸F-FDG PET. The ¹³¹I prompt emission effect was assessed within various energy windows and various activities. We applied a single gamma correction method to a phantom and in vivo mouse model. The ¹³¹I prompt emission fraction was 12% when 300 µCi of ¹³¹I and 100 µCi of FDG were administered, and increased exponentially with escalating ¹³¹I activity for all energy windows. The difference in spill-over ratio was reduced to <5% after ¹³¹I prompt emission correction. In the mouse model, the standard uptake value (SUV) did not differ significantly between FDG PET only (gold standard) and FDG PET after ¹³¹I prompt emission-correction, whereas it was overestimated by 38% before correction. Contrast was improved by 18% after ¹³¹I prompt emission correction. We first found that count contamination on ¹⁸F-FDG follow-up scans due to ¹³¹I spilled-over count after ¹³¹I rituximab tumor targeted therapy. Our developed ¹³¹I prompt emission-correction method increased accuracy during measurement of standard uptake values on ¹⁸F-FDG PET.

Review of cardiovascular imaging in the Journal of Nuclear Cardiology 2018. Part 1 of 2: Positron emission tomography, computed tomography, and magnetic resonance

In this review, we summarize key articles that have been published in the Journal of Nuclear Cardiology in 2018 pertaining to nuclear cardiology with advanced multi-modality and hybrid imaging including positron emission tomography, cardiac-computed tomography, and magnetic resonance. In an upcoming review, we will summarize key articles that relate to the progress made in the field of single-photon emission computed tomography. We hope that these sister reviews will be useful to the reader to navigate the literature in our field.

The continual innovation of commercial PET/CT solutions in nuclear cardiology: Siemens Healthineers

Cardiac PET/CT is an evolving, non-invasive imaging modality that impacts patient management in many clinical scenarios. Beyond offering the capability to assess myocardial perfusion, inflammatory cardiac pathologies, and myocardial viability, cardiac PET/CT also allows for the non-invasive quantitative assessment of myocardial blood flow (MBF) and myocardial flow reserve (MFR). Recognizing the need for an enhanced comprehension of coronary physiology, Siemens Healthineers implemented a sophisticated solution for the calculation of MBF and MFR in 2009. As a result, each aspect of their innovative scanner and image-processing technology seamlessly integrates into an efficient, easy-to-use workflow for everyday clinical use that maximizes the number of patients who potentially benefit from this imaging modality.