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IntroductionRadiotherapy has significantly improved cancer survival rates, but it also comes with certain unavoidable complications. Breast and thoracic irradiation, for instance, can unintentionally expose the heart to radiation, leading to damage at the cellular level within the myocardial structures. Detecting and monitoring radiation-induced heart disease early on is crucial, and several radionuclide imaging techniques have shown promise in this regard. MethodIn this 10-year review, we aimed to identify nuclear medicine imaging modalities that can effectively detect early cardiotoxicity following radiation therapy. Through a systematic search on PubMed, we selected nineteen relevant studies based on predefined criteria. ResultsThe data suggest that incidental irradiation of the heart during breast or thoracic radiotherapy can cause early metabolic and perfusion changes. Nuclear imaging plays a prominent role in detecting these subclinical effects, which could potentially serve as predictors of late cardiac complications.DiscussionHowever, further studies with larger populations, longer follow-up periods, and specific heart dosimetric data are needed to better understand the relationship between early detection of cardiac abnormalities and radiation-induced heart disease.

According to European Society of Cardiology guidelines (ESC2015) for infective endocarditis (IE) management, modified Duke criteria (mDC) are implemented with a degree of clinical suspicion degree, leading to grades such as “possible” or “rejected” IE despite a persisting high level of clinical suspicion. Herein, we evaluate the 18F-FDG PET/CT diagnostic and therapeutic impact in IE suspicion, with emphasis on possible/rejected IE with a high clinical suspicion. Excluding cases of definite IE diagnosis, 53 patients who underwent 18F-FDG PET/CT for IE suspicion were selected and afterwards classified according to both mDC (possible IE/Duke 1, rejected IE/Duke 0) and clinical suspicion degree (high and low IE suspicion). The final status regarding IE diagnosis (gold standard) was based on the multidisciplinary decision of the Endocarditis Team, including the ‘imaging specialist’. PET/CT images of the cardiac area were qualitatively interpreted and the intensity of each focus of extra-physiologic 18F-FDG uptake was evaluated by a maximum standardized uptake value (SUVmax) measurement. Extra-cardiac 18F-FDG PET/CT pathological findings were considered to be a possible embolic event, a possible source of IE, or even a concomitant infection. Based on the Endocarditis Team consensus, final diagnosis of IE was retained in 19 (36%) patients and excluded in 34 (64%). With a sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and global accuracy of 79%, 100%, 100%, 89%, and 92%, respectively, PET/CT performed significantly better than mDC (p = 0.003), clinical suspicion degree (p = 0.001), and a combination of both (p = 0.001) for IE diagnosis. In 41 patients with possible/rejected IE but high clinical suspicion, sensitivity, specificity, PPV, NPV, and global accuracies were 78%, 100%, 100%, 85%, and 90%, respectively. Moreover, PET/CT contributed to patient management in 24 out of 53 (45%) cases. 18F-FDG PET/CT represents a valuable diagnostic tool that could be proposed for challenging IE cases with significant differences between mDC and clinical suspicion degree. 18F-FDG PET/CT allows a binary diagnosis (definite or rejected IE) by removing uncertain diagnostic situations, thus improving patient therapeutic management.

Noninvasive imaging of differences between the molecular properties of cancer and normal tissue has the potential to enhance the detection of tumors. Because overexpression of endogenous transferrin receptor (TfR) has been qualitatively described for various cancers and is presumably due to malignant transformation of cells, TfR may represent a suitable target for application of molecular imaging technologies to increase detection of smaller tumors. In the work reported here, investigation into the biology of this receptor using electron microscopy has demonstrated that iron oxide particles targeted to TfR are internalized and accumulate in lysosomal vesicles within cells. Biochemical analysis of the interaction of imaging probes with cells overexpressing the TfR demonstrated that the extent of accumulation, and therefore probe efficacy, is dependent on the nature of the chemical cross-link between transferrin and the iron oxide particle. These data were utilized to design and synthesize an improved imaging probe. Experiments demonstrate that the novel magnetic resonance imaging (MRI) probe is sensitive enough to detect small differences in endogenous TfR expression in human cancer cell lines. Quantitative measurement of TfR overexpression in a panel of 27 human breast cancer patients demonstrated that 74% of patient cancer tissues overexpressed the TfR and that the sensitivity of the new imaging agent was suitable to detect TfR overexpression in greater than 40% of these cases. Based on a biochemical and cell biological approach, these studies have resulted in the synthesis and development of an improved MRI probe with the best in vitro and in vivo imaging properties reported to date.