Quantitative image reconstruction for dual-isotope parathyroid SPECT/CT: phantom experiments and sample patient studies

Abstract

We investigated the quantitative accuracy of the model-based dual-isotope single-photon emission computed tomography (DI-SPECT) reconstructions that use Klein-Nishina expressions to estimate the scattered photon contributions to the projection data. Our objective was to examine the ability of the method to recover the absolute activities pertaining to both radiotracers: Tc-99m and I-123. We validated our method through a series of phantom experiments performed using a clinical hybrid SPECT/CT camera (Infinia Hawkeye, GE Healthcare). Different activity ratios and different attenuating media were used in these experiments to create cross-talk effects of varying severity, which can occur in clinical studies. Accurate model-based corrections for scatter and cross-talk with CT attenuation maps allowed for the recovery of the absolute activities from DI-SPECT/CT scans with errors that ranged 0-10% for both radiotracers. The unfavorable activity ratios increased the computational burden but practically did not affect the resulting accuracy. The visual analysis of parathyroid patient data demonstrated that our model-based processing improved adenoma/background contrast and enhanced localization of small or faint adenomas.

Radiolabeled liposome imaging determines an indication for liposomal anticancer agent in ovarian cancer mouse xenograft models

“…Tumor accumulation of the radiolabeled liposomes evaluated by SPECT ⁄ CT imaging is ubiquitously applicable to determine indications for liposomal antitumor agents. (28,29) In addition, this method will also be effective for monitoring the course of treatment because the tumor microenvironment is likely to change in response to treatment. Our approach will contribute considerably to optimize cancer therapy toward personalized medicine.…”

A modified TEW approach to scatter correction for In‐111 and Tc‐99m dual‐isotope small‐animal SPECT

“…Cross talk correction methods have been developed for clinical imaging based on convolution subtraction, 6 energy-window subtraction, 7,8 and modeling approaches. [9][10][11][12][13] The accuracy of these methods for small-animal cardiac SPECT imaging has not been evaluated. The modeling methods tend to be the most accurate, but also the most computationally intensive.…”

Simultaneous 99mTc‐MDP/123I‐MIBG tumor imaging using SPECT‐CT: Phantom and constructed patient studies

“…A single SPECT scan produces both 99m Tc and 123 I images, which are perfectly registered. There have been several reports on simultaneous 99m Tc/ 123 I SPECT with many clinical applications, such as for brain, [1][2][3][4] parathyroid, 5,6 and cardiac imaging. 7 To our best knowledge, applying simultaneous 99m Tc/ 123 I SPECT methodology to tumor imaging has not been previously reported.…”