We report our initial clinical experience for image quality and diagnostic performance of a digital PET prototype with time-of-flight (DigitalTF, Philips Healthcare) compared with an analog PET with time-of-flight (GeminiTF PET/CT, Philips Healthcare). Methods: Twenty-one oncologic patients, mean age 58, first underwent clinical FDG PET/CT on the GeminiTF. The scanner table was then withdrawn while the patient remained on the table, and the DigitalTF was inserted between the GeminiTF PET and CT scanner. The patients were scanned for a second time using the same PET field of view with CT from GeminiTF for attenuation correction. Two readers reviewed the two sets of PET/CT images for overall image quality, lesion conspicuity and sharpness. They counted the number of suspicious, FDG avid lesions and provided the TNM staging for the five patients referred for initial staging. Standardized uptake values (SUV) and SUV gradients as a measure of lesion sharpness were obtained. Results: DigitalTF showed better image quality compared with GeminiTF. In side-by-side comparison using a 5-point scale, lesion conspicuity (4.3 ± 0.6), lesion sharpness (4.3 ± 0.6) and diagnostic confidence (3.4 ± 0.7) were better with DigitalTF compared with GeminiTF, P < 0.01. In 52 representative lesions, lesion maximum SUV was 36% higher with DigitalTF than with GeminiTF, lesion-to-blood pool SUV ratio was 59% higher and SUV gradient was 51% higher, with good correlation between the two scanners. Lesions < 1.5 cm showed a greater increase in SUV from GeminiTF to DigitalTF compared to those ≥ 1.5 cm. DigitalTF showed additional eight suspicious lesions in 5 of 21 patients that were not seen at GeminiTF. In the 15 restaging patients, the true negative rate was 100% and true positive rate was 78% for both scanners. In the five patients for initial staging, DigitalTF lead to upstaging in two patients and showed the same staging in the other three patients compared with GeminiTF. Conclusion: DigitalTF provides better image quality, diagnostic confidence and accuracy compared with GeminiTF. It may be most beneficial in detecting small tumor lesions and disease staging.

Gadobenate dimeglumine administrations lead to increased MRI signal intensity in the dentate nucleus. Background Increased cerebral signal intensity (SI) has been reported in patients undergoing MRI with gadolinium-based contrast agents (GBCAs). Published data on gadobenate dimeglumine have been so...

Hybrid imaging with F-18 fludeoxyglucose positron emission tomography/magnetic resonance imaging (FDG PET/MRI) has increasing clinical applications supplementing conventional ultrasound, CT, and MRI imaging as well as hybrid PET/CT imaging in assessing cervical, endometrial, and ovarian cancer. This article summarizes the existing literature and discusses the emerging role of hybrid PET/MRI in gynecologic malignancies. Thus, far, the published literature on the applications of FDG PET/MRI shows that it can have a significant impact on patient management by improving the staging of the cancers compared with PET/CT, influencing clinical decision and treatment strategy. For disease restaging, current literature indicates that PET/MRI performs equivalently to PET/CT. There appears to be a mild-moderate inverse correlation between standard-uptake-value (SUV) and apparent-diffusion-coefficient (ADC) values, which could be used to predict tumor grading and risk stratification. It remains to be seen as to whether multi-parametric PET/MRI imaging could prove valuable for prognostication and outcome. PET/MRI provides the opportunity for reduced radiation exposure, which is particularly relevant for a young female in need of multiple scans for treatment monitoring and follow-up. Fast acquisition protocols and optimized methods for attenuation correction are still evolving. Major limitations of PET/MRI remains such as suboptimal detection of small pulmonary nodules and lack of utility for radiation treatment planning, which pose an impediment in making PET/MRI a viable one-stop-shop imaging option to compete with PET/CT.

Background and Purpose. Radium-223 dichloride (Xofigo®, Bayer HealthCare Pharmaceuticals Inc.) is the first α-particle emitter therapeutic agent approved by the FDA, with benefits in overall survival and delay in symptomatic skeletal event for patients with metastatic castrate-resistant prostate cancer (CRPC). Recent post hoc analyses of the phase III ALSYMPCA trial support the previously established safety profile as well as therapeutic effect and clinical outcome of Radium-223. Currently, Radium-223 is approved as a single agent therapy for metastatic CRPC. Clinical trials are currently investigating Radium-223 in additional clinical settings such as earlier asymptomatic disease and in combination with other agents including hormonal therapeutic agents and immunotherapeutic as well as chemotherapeutic agents. Trials are also ongoing in patients with other primary cancers such as breast cancer, thyroid cancer, and renal cancer metastatic to bone. In this article, the physics and radiobiology, as well as a literature update on the use of Radium-223, are provided along with case presentations, aiming at a better appreciation of research data as well as the assimilation of research data into clinical practice.