Case report: brown fat accumulation of Tc-99m macroaggregated albumin in a lung perfusion study in a patient with multiple lung arteriovenous malformations and right-to-left shunting

An 18-year-old man was preoperatively assessed for a varicocele and found to be hypoxemic. A Tc-99m macroaggregated albumin lung perfusion scan showed right-to-left shunting, evidenced by increased radiotracer uptake in the brain, kidneys, thyroid gland, and bilateral supraclavicular areas, a typical location for brown adipose tissue. Chest computerized tomography angiogram study showed supraclavicular fat density areas and multiple pulmonary arteriovenous malformations. The authors report a rare case of brown fat visualization on a lung perfusion scan in a patient with right-to-left shunting, likely because of increased perfusion to activated brown adipose tissue

Joint EANM, SNMMI and IAEA enabling guide: How to set up a theranostics centre

The theranostics concept using the same target for both imaging and therapy dates back to the middle of the last century, when radioactive iodine was first used to treat thyroid diseases. Since then, radioiodine has become broadly established clinically for diagnostic imaging and therapy of benign and malignant thyroid disease, worldwide. However, only since the approval of SSTR2-targeting theranostics following the NETTER-1 trial in neuroendocrine tumours and the positive outcome of the VISION trial has theranostics gained substantial attention beyond nuclear medicine. The roll-out of radioligand therapy for treating a high-incidence tumour such as prostate cancer requires the expansion of existing and the establishment of new theranostics centres. Despite wide global variation in the regulatory, financial and medical landscapes, this guide attempts to provide valuable information to enable interested stakeholders to safely initiate and operate theranostics centres. This enabling guide does not intend to answer all possible questions, but rather to serve as an overarching framework for multiple, more detailed future initiatives. It recognizes that there are regional differences in the specifics of regulation of radiation safety, but common elements of best practice valid globally

The “water-ida”: A simple means to separate duodenal from gallbladder activity on cholescintigraphic studies

In some 99m Tc-iminodiacetic acid studies, separation of the gallbladder from the duodenum can be difficult, despite multiple views. When faced with this problem, we have had the patient ingest 250 cc of tap water. This ingestion clears the duodenum of activity and has allowed us to see the residual activity in the gallbladder. This “waterida” view may be a useful addition in difficult to interpret hepatobiliary studies.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46845/1/259_2004_Article_BF00276464.pd

Repeatability of brown adipose tissue measurements on FDG PET/CT following a simple cooling procedure for BAT activation

Brown Adipose Tissue (BAT) is present in a significant number of adult humans and can be activated by exposure to cold. Measurement of active BAT presence, activity, and volume are desirable for determining the efficacy of potential treatments intended to activate BAT. The repeatability of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) measurements of BAT presence, activity, and volume under controlled conditions has not been extensively studied. Eleven female volunteers underwent double baseline FDG PET imaging performed following a simple, regional cold intervention intended to activate brown fat. The cold intervention involved the lightly-clothed participants intermittently placing their feet on a block of ice while sitting in a cooled room. A repeat study was performed under the same conditions within a target of two weeks. FDG scans were obtained and maximum standardized uptake value adjusted for lean body mass (SULmax), CT Hounsfield units (HU), BAT metabolic volume (BMV), and total BAT glycolysis (TBG) were determined according to the Brown Adipose Reporting Criteria in Imaging STudies (BARCIST) 1.0. A Lin's concordance correlation (CCC) of 0.80 was found for BMV between test and retest imaging. Intersession BAT SULmax was significantly correlated (r = 0.54; p < 0.05). The session #1 mean SULmax of 4.92 ± 4.49 g/mL was not significantly different from that of session #2 with a mean SULmax of 7.19 ± 7.34 g/mL (p = 0.16). BAT SULmax was highly correlated with BMV in test and retest studies (r ≥ 0.96, p < 0.001). Using a simplified ice-block cooling method, BAT was activated in the majority (9/11) of a group of young, lean female participants. Quantitative assessments of BAT SUL and BMV were not substantially different between test and retest imaging, but individual BMV could vary considerably. Intrasession BMV and SULmax were strongly correlated. The variability in estimates of BAT activity and volume on test-retest with FDG should inform sample size choice in studies quantifying BAT physiology and support the dynamic metabolic characteristics of this tissue. A more sophisticated cooling method potentially may reduce variations in test-retest BAT studies

Optimal definition of biological tumor volume using positron emission tomography in an animal model

BACKGROUND: The goal of the study is to investigate (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG-PET)’s ability to delineate the viable portion of a tumor in an animal model using cross-sectional histology as the validation standard. METHODS: Syngeneic mammary tumors were grown in female Lewis rats. Macroscopic histological images of the transverse tumor sections were paired with their corresponding FDG micro-PET slices of the same cranial-caudal location to form 51 pairs of co-registered images. A binary classification system based on four FDG-PET tumor contouring methods was applied to each pair of images: threshold based on (1) percentage of maximum tumor voxel counts (C(max)), (2) percentage of tumor peak voxel counts (C(peak)), (3) multiples of liver mean voxel counts (C(liver)) derived from PERCIST, and (4) an edge-detection-based automated contouring system. The sensitivity, which represented the percentage of viable tumor areas correctly delineated by the gross tumor area (GTA) generated from a particular tumor contouring method, and the ratio (expressed in percentage) of the overestimated areas of a gross tumor area (GTA(OE))/whole tumor areas on the macroscopic histology (WTA(H)), which represented how much a particular GTA extended into the normal structures surrounding the primary tumor target, were calculated. RESULTS: The receiver operating characteristic curves of all pairs of FDG-PET images have a mean area under the curve value of 0.934 (CI of 0.911–0.954), for representing how well each contouring method accurately delineated the viable tumor area. FDG-PET single value threshold tumor contouring based on 30 and 35 % of tumor C(max) or C(peak) and 6 × C(liver) + 2 × SD achieved a sensitivity greater than 90 % with a GTA(OE)/WTA(H) ratio less than 10 %. Contouring based on 50 % of C(max) or C(peak) had a much lower sensitivity of 67.2–75.6 % with a GTA(OE)/WTA(H) ratio of 1.1–1.7 %. Automated edge detection was not reliable in this system. CONCLUSIONS: Single-value-threshold tumor contouring using (18)F-FDG-PET is able to accurately delineate the viable portion of a tumor. 30 and 35 % of C(max), 30 and 35 % of C(peak), and 6 × C(liver) + 2 × SD are three appropriate threshold values to delineate viable tumor volume in our animal model. The commonly used threshold value of 50 % of C(max) or C(peak) failed to detect one third of the viable tumor volume in our model

Gastric xenon trapping mimicking COPD: Recognition using an effervescent agent

Trapping of xenon 133 in the stomach due to gas swallowing can mimic xenon 133 retention in the left lower lobe due to obstructive lung disease on pulmonary ventilation/perfusion studies. In such cases, ingestion of sodium citrate-bicarbonate-simethicone crystals, which from CO 2 gas on contact with water, can distend the xenoncontaining stomach and allow clear delineation of its gastric location. This approach is useful in selected cases and may help avoid false-positive diagnoses of obstructive airways disease.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46824/1/259_2004_Article_BF00276710.pd

Increased genital uptake of 99m Tc red blood cells: A potential cause of false-positive studies for gastrointestinal bleeding

We have recently seen several 99m Tc labeled red blood (Tc-RBC) cell studies, for the localization of gastrointestinal (GI) bleeding, which were difficult to interpret because of increased activity in the low abdomen, which was found due to male genital activity. To examine the extent of this problem six recent Tc-RBC studies for GI bleeding in males were examined for the presence of penile activity. Penile activity was seen in all males and was marked enough to require additional views in four. Lateral views readily separated penile from rectal activity, showing that the activity was not posteriorly located. Twenty-four Tc-RBC studies on females were also examined. Although modest levels of perineal activity could be seen, this did not cause problems in diagnosis. Attention to this common problem in males should prevent false-positive diagnoses of GI bleeding from the rectum.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46844/1/259_2004_Article_BF00448548.pd

A semi-automated fluorescent (SAF) assay using viable, whole cells for screening hybridoma supernatants

In the production of monoclonal antibodies, a rapid, sensitive, accurate assay is needed for the critical step of screening. We report the modification of an assay using viable whole cells for screening hybridoma supernatants. The modified assay uses fluorescent second antibodies for detection and has been adapted to an instrument capable of automating a number of assay steps. The modified assay is compared to a dot radioimmunoassay developed and used in our laboratory. The fluorescence assay is highly sensitive but shows more background effect, especially in samples with high protein content, such as ascites. The automated fluorescence assay is very rapid, capable of completing an assay in less than 90 min, and can be performed with minimal operator involvement. The assay was performed successfully with several different antibodies and cell types. This screening procedure should be especially useful for laboratories with large numbers of fusions to evaluate.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26678/1/0000222.pd