Lymphoma is one of the most common cancers worldwide, categorized into Hodgkin lymphoma and non-Hodgkin lymphoma. ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG PET) has become an essential imaging tool for evaluating patients with lymphoma in terms of initial diagnosis, staging, prognosis, and treatment response assessment. Recent advancements in imaging technology and methodologies, along with the development of artificial intelligence, have revolutionized the evaluation of complex imaging data, enhancing the diagnostic and predictive power of PET in lymphoma. However, FDG is not cancer-specific, but it primarily reflects glucose metabolism, which has prompted the investigation of alternative PET tracers to address this limitation. Novel PET radiotracers, such as fibroblast activation protein inhibitors targeting the tumor microenvironment, have recently shown promising results in evaluating various malignancies compared to FDG PET. Furthermore, with the rapid advancements in immunotherapy and the favorable imaging properties of ⁸⁹Zr, immunoPET has emerged as a promising modality, offering insights into the functional and molecular status of the immune system. ImmunoPET can also facilitate the development of new antibody therapeutics and radioimmunotherapy by providing pharmacokinetic and pharmacodynamic data. This review provides comprehensive insights into the current clinical applications of FDG PET in lymphoma, while also exploring novel PET imaging radiotracers beyond FDG, discussing their mechanisms of action and potential impact on patient management.

We investigated whether the interpretation of breast-specific gamma imaging (BSGI) with visual and semiquantitative analyses can improve the diagnosis of breast cancer. The records of 114 women (mean age±SD, 49.6±9.8 years) who underwent BSGI, mammography, and ultrasound to evaluate a breast lesion or lesions were reviewed retrospectively. The breast lesions identified with BSGI were compared with those identified with mammography and ultrasound. BSGI was first interpreted visually, and then a semiquantitative analysis was performed. For the semiquantitative analysis, the uptake ratio for each breast lesion was calculated by dividing the tumor uptake by the contralateral normal breast uptake. Four of the 114 patients had two breast lesions, so a total of 118 breast lesions (42 malignant lesions and 76 benign lesions) were evaluated. A BSGI uptake ratio cutoff of 1.5, with values less than 1.5 indicating negative for cancer, as determined by receiver operating characteristic curve analysis of our data (area under curve, 0.874), was used for semi-quantitative analysis. The sensitivity and specificity of BSGI with visual analysis alone for assessing malignant breast lesions were 76.2% (32/42) and 81.6% (62/76), respectively. For BSGI with visual and semiquantitative analyses, the sensitivity and specificity were 76.2% (32/42) and 92.1% (70/76), respectively. The sensitivity and specificity for mammography were 57.1% (24/42) and 81.6% (62/76), respectively. For ultrasound, the respective values were 97.6% (41/42) and 61.8% (47/76). BSGI with visual and semiquantitative analyses had a significantly higher specificity than BSGI with visual analysis alone, mammography, and ultrasound (all, p<0.01). Semiquantitative analysis of BSGI with visual interpretation may be a useful complementary method for evaluating malignant breast lesions.