Advances in SPECT and PET Reconstruction for Theranostics: From Diagnosis to Therapy

The theranostic paradigm enables personalization of treatment by selecting patients with a diagnostic radiopharmaceutical and monitoring therapy of a matched therapeutic isotope. This strategy relies on accurate image reconstruction of both pretherapy and post-therapy images for patient selection and monitoring treatment. However, traditional reconstruction methods are hindered by challenges such as crosstalk in multi-isotope imaging and extremely low-count data when imaging of alpha-emitting therapeutics. Additionally, to fully realize the benefits of new imaging systems being developed for theranostic applications, advanced reconstruction techniques are needed. This review highlights recent progress and addresses critical challenges and unmet needs in theranostic image reconstruction.