Positron Range Corrections and Denoising Techniques for Gallium-68 PET Imaging: A Literature Review

Abstract

Gallium-68 (68Ga) is characterized by relatively high positron energy compared to Fluorine-18 (18F), causing substantial image quality degradation. Furthermore, the presence of statistical noise can further degrade image quality. The aim of this literature review is to identify the recently developed positron range correction techniques for 68Ga, as well as noise reduction methods to enhance the image quality of low count 68Ga PET imaging. The search engines PubMed and Scopus were employed, and we limited our research to published results from January 2010 until 1 August 2022. Positron range correction was achieved by using either deblurring or deep learning approaches. The proposed techniques improved the image quality and, in some cases, achieved an image quality comparable to 18F PET. However, none of these techniques was validated in clinical studies. PET denoising for 68Ga-labeled radiotracers was reported using either reconstruction-based techniques or deep learning approaches. It was demonstrated that both approaches can substantially enhance the image quality by reducing the noise levels of low count 68Ga PET imaging. The combination of 68Ga-specific positron range correction techniques and image denoising approaches may enable the application of low-count, high-quality 68Ga PET imaging in a clinical setting.

Chemical radioanalysis of production of positron-emitting radioisotope Gallium-68 via (p,n) and (p,2n) reactions using compact cyclotron for tomography applications

“…68 Ga has greater positron kinetic energy, and therefore higher positron range, and is anticipated to possess a lower spatial image resolution compared to 18 F with average positron energy of 0.25 MeV and maximum of 0.63 MeV. Nevertheless, both experimental measurements and computational analyzes indicates a similarly great image quality for these two radionuclides with an assumed detector or scanner resolution of 2.5–4 mm [ 18 , 19 ]. Meanwhile, 68 Ga equals the biological half-life of various peptides utilized for positron imaging by virtue of its localization to the target, rapid blood clearance, and rapid diffusion.…”

Artificial intelligence-based 68Ga-DOTATOC PET denoising for optimizing 68Ge/68Ga generator use throughout its lifetime

“…Denoising techniques for 68 Ga-labeled radiotracers in PET imaging have been explored using both reconstruction-based methods and deep-learning techniques. It has been shown that both strategies can significantly improve the image quality by decreasing the noise level in low-dose 68 Ga PET scans ( 15 ).…”