Gallium-68-Labeled Prostate-Specific Membrane Antigen-11 PET/CT of Prostate and Nonprostate Cancers.

OBJECTIVE. The purpose of this study is to provide a concise summary of the current experience with 68Ga-labeled prostate-specific membrane antigen (PSMA)-11 imaging of prostate and nonprostate malignancies and benign conditions. CONCLUSION. PSMA is overexpressed in prostate cancer and in the neovasculature of many other malignancies. The relevance of PSMA as a biologic target, coupled with advances in the design, synthesis, and evaluation of PSMA-based radionuclides for imaging and therapy, is anticipated to play a major role in patient care.

The role of PET/CT in the evaluation of skeletal metastases.

Osseous metastatic disease from malignancy is a common occurrence with significant patient morbidity and mortality as well as increasing health care expenditures. Patient management plans frequently change with the identification of skeletal metastasis and the upstaging of disease status. Bone scintigraphy remains the current mainstay of diagnostic imaging procedures in nuclear medicine for the early detection of skeletal metastasis owing to their high sensitivity. Emerging positron tracers and the increasing use and availability of hybrid single-photon emission computed tomography and positron emission tomography (PET)/computed tomography machines enable physicians to diagnose metastatic disease in bones with superior accuracy. This review introduces the basics of PET and the commonly used positron tracers used to evaluate skeletal metastases.

The American College of Nuclear Medicine Guidance on Operating Procedures for a Nuclear Medicine Facility During COVID-19 Pandemic.

ABSTRACT: The novel coronavirus 2 pandemic is causing widespread disruption in everyday life necessitating urgent and radical adaptations in operating procedures at nuclear medicine facilities. The potential for causing severe illness, COVID-19, calls for strict observance of preventive measures aimed to mitigate the spread of the virus. The threat of COVID-19 is particularly serious as there is no vaccine and no specific antiviral therapy. Further complications are introduced by shortages of personal protective equipment for healthcare workers who have direct contact with patients and effective testing to identify infected patients, raising the need for delaying some testing and therapies. Certain vulnerable segments of the general population have been identified (advanced age and certain comorbidities), which should heighten further their preventive efforts. Therefore, this guidance is intended to be operationalized depending on a facility's specific needs and local disease prevalence.

18F-Fluorodeoxyglucose-positron Emission Tomography/Computed Tomography Imaging of Metastatic Nasopharyngeal Cancer with Emphasis on the Distribution of Bone Metastases.

Distant metastases change the prognosis of patients with nasopharyngeal carcinoma (NPC) which most commonly metastasizes to the bone. 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) is reported as useful in imaging NPC metastases. Our study assesses the incidence and distribution of bone metastases detected by 18F-FDG PET/CT in NPC. 717 18F-FDG PET/CT scan reports of histologically proven NPC patients imaged in Singapore General Hospital, Singapore, between 2003 and 2009 were reviewed for the total number of metastases (scanned from vertex to mid-thigh) and analyzed for distribution. Of the 709 FDG avid metastases in these reports, 357/709 (50.35%) were locoregional nodal metastasis and 352/709 (49.65%) were distant metastases of which 192/709 (27.08%) of total metastases and 54.54% of distant metastases (192/352) were in the bones. The majority of the bone lesions 125/192 (65.1%) were in the axial skeleton with 109/192 (56.77%) in the lower skeleton (thoracolumbar spine, sacrum, and pelvis). The incidence of bone metastases in our study (27.08%) was higher than that reported in other studies, for example, 15% by Liu et al. and 11% (230 patients) by Caglar et al. Bone metastases have been reported in the femurs and the feet and as such some metastases may have been outside the field of view of the scans. In our study, 27% of FDG avid NPC metastases are in the bones.

The incidence and sites of Nasopharyngeal carcinoma (NPC) metastases on FDG PET/CT scans.

INTRODUCTION: The only investigation to determine if a whole body FDG PET/CT scan is helpful in the evaluation of NPC is a study from Stanford. In this study, 26 patients with whole body PET/CT, were evaluated for lesions below adrenals and showed that 7.7% of distant metastases were below adrenals. Our study comparing distant metastases below diaphragm with Stanford study to evaluate the need for whole body PET/CT. MATERIAL AND METHODS: Reports of NPC patients in Singapore General Hospital were reviewed. The lesions were analyzed for total number and number below diaphragm. The lesions below the diaphragm were further analyzed if they were solitary or involved multiple areas and if any additional lesions were above diaphragm. RESULTS: 717 reports were included in final analysis. The number of FDG avid lesions in these reports was 709. Distant metastases represented 352 of the 709 lesions. The number of lesions below diaphragm was 152, of the lesions below diaphragm only 16 of lesions have no co-existing distant metastases above diaphragm. From these lesions, there were only 12 solitary lesions. The other 4 has concurrent metastases but all localized below diaphragm. CONCLUSION: Compared to Stanford study, number of reports is more representative in this study and the yield is much lower (7.7% versus 2.26%). From the results of our study we can consider limiting the scan area from vertex to below diaphragm. However, the symptoms and clinical presentation of the patient will further direct the requesting physician in the area to be imaged.

Sampling circulating tumor cells for clinical benefits: how frequent?

Circulating tumor cells (CTCs) are cells shed from tumors or metastatic sites and are a potential biomarker for cancer diagnosis, management, and prognostication. The majority of current studies use single or infrequent CTC sampling points. This strategy assumes that changes in CTC number, as well as phenotypic and molecular characteristics, are gradual with time. In reality, little is known today about the actual kinetics of CTC dissemination and phenotypic and molecular changes in the blood of cancer patients. Herein, we show, using clinical case studies and hypothetical simulation models, how sub-optimal CTC sampling may result in misleading observations with clinical consequences, by missing out on significant CTC spikes that occur in between sampling times. Initial studies using highly frequent CTC sampling are necessary to understand the dynamics of CTC dissemination and phenotypic and molecular changes in the blood of cancer patients. Such an improved understanding will enable an optimal, study-specific sampling frequency to be assigned to individual research studies and clinical trials and better inform practical clinical decisions on cancer management strategies for patient benefits.

Usefulness of F-18 fluorodeoxyglucose positron emission tomography/computed tomography in a case of choriocarcinoma presenting as pulmonary embolism.

This case demonstrates the utility of performing F-18 fluorodeoxyglucose positron emission tomography/computed tomography for the investigation of an unresolving pulmonary embolus, where early diagnosis of tumor thrombus or primary neoplastic conditions of the pulmonary artery may be made. Choriocarcinoma presenting within the pulmonary artery is rare although a literature review shows that a number of important differential diagnoses of hypermetabolic pulmonary lesions should be kept in mind.

Intensely hypermetabolic extra-axial brainstem tumor in Erdheim-Chester disease.

Erdheim-Chester disease is a rare non-Langerhans cell histiocytosis characterized by progressive histiocytic proliferation with multiorgan involvement, typically of the kidney, skin, brain, and lung, and less frequently, the heart and retro-orbital tissue. Fluorine-18 fluorodeoxyglucose positron emission tomography (F-18 FDG PET) plays an important role in the management of this disease. It has been reported that FDG PET imaging allows accurate evaluation of the extent of the disease at baseline, as well as assessment of response to any specific therapy. In this case, a 57-year-old Chinese man presented with functional decline and a urinary tract infection. He had a prior history of xanthogranulomas of bilateral canthal masses. On imaging, he was found to have left hydronephrosis, diffuse urothelial thickening, increased density of the perinephric fat, mural thickening of the descending aorta and soft tissue masses along the posterior wall of the right atrium extending into the region of the interatrial septum and involving the right atrioventricular groove. Histopathology revealed retroperitoneal fibrosis. An IV contrast-enhanced FDG PET scan showed increased activity in a previously unidentified brain stem mass and the shafts of bilateral femora. Varying levels of FDG uptake were seen in the other lesions.