99mTc-Tilmanocept Versus 99mTc-Sulfur Colloid in Lymphoscintigraphy: Sentinel Lymph Node Identification and Patient-Reported Pain.

Lymphoscintigraphy plays a vital role in sentinel lymph node (SLN) identification in oncologic breast surgery. The effectiveness of SLN localization and the degree of patient pain were compared between filtered 99mTc-sulfur colloid (99mTc-SC) and 99mTc-tilmanocept. Methods: A retrospective review of patients undergoing lymphoscintigraphy for breast cancer using 99mTc-SC (June 1, 2010, to December 31, 2011) or 99mTc-tilmanocept (June 1, 2013, to January 31, 2014) was performed. SLN appearance time and uptake, SLN pathology, proportion of positive SLNs removed, and pain scores were compared for each radiopharmaceutical using the χ2 test, Fisher exact test, and unequal variance t test, as appropriate. Results: In total, 76 patients, with 86 evaluated axillae, underwent lymphoscintigraphy: 29 with 99mTc-SC and 47 with 99mTc-tilmanocept. The mean SLN appearance time was 11.0 min for 99mTc-SC and 19.3 min for 99mTc-tilmanocept (P = 0.003). There was no difference in the mean transit uptake percentage: 2.2% for 99mTc-SC and 1.9% for 99mTc-tilmanocept (P = 0.55). 99mTc-tilmanocept identified a greater proportion of intraoperative blue nodes than did 99mTc-SC (P = 0.03). There was no significant difference between 99mTc-SC and 99mTc-tilmanocept in the number of SLNs removed, number of patients with positive SLNs, or pain score. Conclusion: 99mTc-SC use in lymphoscintigraphy is an acceptable alternative to 99mTc-tilmanocept for SLN detection in breast cancer, on the basis of the similarity in intraoperative SLN identification and pain scores.

First PET Imaging Studies With 63Zn-Zinc Citrate in Healthy Human Participants and Patients With Alzheimer Disease.

Abnormalities in zinc homeostasis are indicated in many human diseases, including Alzheimer disease (AD). 63Zn-zinc citrate was developed as a positron emission tomography (PET) imaging probe of zinc transport and used in a first-in-human study in 6 healthy elderly individuals and 6 patients with clinically confirmed AD. Dynamic PET imaging of the brain was performed for 30 minutes following intravenous administration of 63Zn-zinc citrate (∼330 MBq). Subsequently, body PET images were acquired. Urine and venous blood were analyzed to give information on urinary excretion and pharmacokinetics. Regional cerebral 63Zn clearances were compared with 11C-Pittsburgh Compound B (11C-PiB) and 18F-fluorodeoxyglucose (18F-FDG) imaging data. 63Zn-zinc citrate was well tolerated in human participants with no adverse events monitored. Tissues of highest uptake were liver, pancreas, and kidney, with moderate uptake being seen in intestines, prostate (in males), thyroid, spleen, stomach, pituitary, and salivary glands. Moderate brain uptake was observed, and regional dependencies were observed in 63Zn clearance kinetics in relationship with regions of high amyloid-ß plaque burden (11C-PiB) and 18F-FDG hypometabolism. In conclusion, zinc transport was successfully imaged in human participants using the PET probe 63Zn-zinc citrate. Primary sites of uptake in the digestive system accent the role of zinc in gastrointestinal function. Preliminary information on zinc kinetics in patients with AD evidenced regional differences in clearance rates in correspondence with regional amyloid-ß pathology, warranting further imaging studies of zinc homeostasis in patients with AD.