Attenuation Correction Techniques in Nuclear Medicine - SPECT, PET

Abstract

In contemporary clinical practice, Anatomical imaging modalities are improved by nuclear medicine imaging, which provides molecular and functional insights. Nuclear medicine imaging has emerged as a crucial tool in modern clinical practice, providing molecular and functional insights that improve anatomical imaging modalities. Among its often-used methods, single-photon emission computed tomography (SPECT) and positron emission tomography (PET) are essential for the diagnosis, staging, and follow-up of a wide range of illnesses, such as neurological, cardiovascular, and cancer conditions. However, photon attenuation has a major impact on the precision and clinical usefulness of PET and SPECT, a phenomenon in which photons are absorbed or scattered by tissues before reaching the detector. Attenuation leads to image degradation, artefacts, and errors in tracer quantification, ultimately affecting diagnostic precision and treatment planning. This study presents a thorough analysis of nuclear medicine imaging attenuation correction strategies, emphasizing both conventional and modern approaches. Foundational approaches such as uniform attenuation maps, Chang’s algorithm, and iterative reconstruction are discussed alongside the revolutionary contributions of hybrid imaging techniques that combine anatomical data to produce precise attenuation maps, such as PET/CT, SPECT/CT, and PET/MR. Additionally, the potential of developments in artificial intelligence (AI), such as deep learning (DL) and machine learning (ML) to enhance image reconstruction, automate attenuation correction, and simplify workflow. Clinical applications across cardiology, oncology, neurology, musculoskeletal imaging, and infection detection are highlighted to demonstrate the impact of accurate attenuation correction in improving diagnostic confidence and patient outcomes. By tracing the evolution of techniques and highlighting recent innovations, this paper underscores the central role of attenuation correction in maximizing the diagnostic and therapeutic potential of nuclear medicine imaging.