Applications of machine learning and deep learning in SPECT and PET imaging: General overview, challenges and future prospects.

The integration of positron emission tomography (PET) and single-photon emission computed tomography (SPECT) imaging techniques with machine learning (ML) algorithms, including deep learning (DL) models, is a promising approach. This integration enhances the precision and efficiency of current diagnostic and treatment strategies while offering invaluable insights into disease mechanisms. In this comprehensive review, we delve into the transformative impact of ML and DL in this domain. Firstly, a brief analysis is provided of how these algorithms have evolved and which are the most widely applied in this domain. Their different potential applications in nuclear imaging are then discussed, such as optimization of image adquisition or reconstruction, biomarkers identification, multimodal fusion and the development of diagnostic, prognostic, and disease progression evaluation systems. This is because they are able to analyse complex patterns and relationships within imaging data, as well as extracting quantitative and objective measures. Furthermore, we discuss the challenges in implementation, such as data standardization and limited sample sizes, and explore the clinical opportunities and future horizons, including data augmentation and explainable AI. Together, these factors are propelling the continuous advancement of more robust, transparent, and reliable systems. [Display omitted] • A comprehensive overview of the state-of-the-art in Machine Learning and Deep Learnig applications in SPECT and PET imaging. • ML algorithms in imaging systems offer opportunities for improved diagnostic accuracy and radiopharmaceutical optimization. • Challenges include interpretability of DL models, limited labeled datasets, imaging protocols or regulatory approval. • Ongoing efforts focus on algorithm's interpretability, multimodal data fusion and real-time decision support systems. [ABSTRACT FROM AUTHOR]