Journal of nuclear medicine technology最新文献

This phantom study aimed to optimize the noise-suppression parameter (β) and the edge-preservation parameter (γ) values in the block sequential regularized expectation maximization (BSREM) reconstruction method for ¹²³I-2-β-carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl)nortropane striatal SPECT using a ring-type cadmium-zinc-telluride camera. Methods: We used a striatum phantom filled with an ¹²³I solution, with adjusted concentrations in the left and right caudate and left and right putamen. The phantom was scanned for 120 min using the StarGuide system, and 20-min SPECT data were extracted from the total acquisition. Using the BSREM method, we generated 42 reconstructed images by varying β and γ. We calculated the percent coefficient of variation and percent contrast for each image. Visual evaluations were conducted by a nuclear medicine physician and 2 technologists. Additionally, we calculated the striatal uptake ratio (SUR) and the ratio of the left caudate SUR to putamen SUR in the left striatum (left striatal ratio). Results: The percent coefficient of variation decreased as the β value increased, whereas percent contrast increased as the γ value increased. We conducted a visual evaluation of 15 reconstructed images selected by physical assessment. Images reconstructed with a β value of 0.03 with a γ value of 5 and those with a β value of 0.05 with a γ value of 10 were deemed suitable for diagnostic purposes because of their accurate depiction of tracer accumulation in each striatal region. SUR and left striatal ratio were comparable for these 2 image sets. Conclusion: Evaluation of the optimal conditions for striatal SPECT imaging with BSREM reconstruction revealed that the optimal β value and γ value combinations were a β value of 0.03 and γ value of 5 and a β value of 0.05 and γ value of 10.

A 65-y-old woman with multiple cardiovascular risk factors presented with atypical chest pain, prompting a 1-d pharmacologic stress myocardial perfusion test using ^99mTc sestamibi. Initial interpretation suggested ischemia, but closer inspection revealed increased right ventricular uptake and increased left ventricular chamber size at stress, indicative of significant 3-vessel coronary artery disease (CAD). These findings were confirmed by cardiac catheterization, showing 3-vessel disease, including significant left main CAD. The patient underwent coronary artery bypass graft surgery. This case highlights the importance of meticulous SPECT image interpretation, particularly focusing on right ventricular uptake and transient ischemic dilation, to accurately diagnose severe CAD and improve cardiovascular outcomes.

[^99mTc]-3,3-diphosphono-1,2-propanodicarboxylic acid bone scintigraphy was used to differentiate between posterior impingement syndrome and Haglund syndrome in a 34-y-old man with unclear right-sided ankle pain. The patient had an accessory os trigonum bilaterally, and previous x-ray, MRI, and CT were inconclusive. Using SPECT/CT with new iterative reconstruction algorithms based on CT images, the pathologic activation of bone metabolism at the right-sided os trigonum and the adjacent talus joint was revealed. Other causes of posterior ankle pain were ruled out, and posterior impingement syndrome was diagnosed.

This study investigated the safety, biodistribution, and dosimetry of ⁶⁸Ga-hexavalent lactoside (⁶⁸Ga-NOTA-HL), a PET tracer targeting asialoglycoprotein receptors (ASGPRs) on hepatocytes. ASGPRs, key for glycoprotein homeostasis, serve as a valuable biomarker of liver function. ⁶⁸Ga-NOTA-HL demonstrated excellent safety in 12 healthy volunteers with no adverse events. Biodistribution studies revealed high liver uptake with minimal uptake in other organs, consistent with ASGPR targeting. The effective dose was 0.0289 mSv/MBq, indicating low radiation exposure. These findings suggest ⁶⁸Ga-NOTA-HL PET/CT holds significant promise as a safe and effective imaging technique for assessing liver function. The high liver specificity and extremely low background activity provide a strong foundation for further clinical investigations into its potential for evaluating liver function in various clinical settings, including the assessment of liver reserve in patients with liver diseases.

Many benign bone lesions mimic skeletal metastases from thyroid cancer on imaging and even may have high metabolic uptake on ¹⁸F-FDG PET/CT. It becomes crucial to distinguish these hypermetabolic lesions (benign vs. metastasis), especially in patients with thyroglobulin elevation and negative iodine scan. The index case describes a patient with thyroid cancer having thyroglobulin elevation and negative iodine scan with a hypermetabolic aneurysmal bone cyst mimicking skeletal metastasis.

Nuclear medicine scintigraphy using ^99mTc-pyrophosphate has proven valuable in the diagnosis of cardiac transthyretin amyloidosis in recent years. However, there is still confusion over the optimal imaging time points. The American Society of Nuclear Cardiology has recommended different imaging time points over the last decade. We aimed to determine whether single- or dual-time-point imaging is required for reporting purposes and which time point would be the most appropriate if a single time point was to be considered. Methods: Cardiac amyloid scans using ^99mTc-pyrophosphate acquired from 2017 to 2023 were retrieved from our Picture Archiving and Communications System. Scans with static views and SPECT/CT images of the chest for both imaging time points, at 1 h (early) and 3 h (delayed) after injection, were included. Each study was independently read by 3 nuclear medicine physicians. Original clinical reports using both imaging time points were used as a reference to calculate the accuracy of a single time point. Results: In total, 70 patients were included in this study. Reports of cardiac amyloid studies using any single-time-point imaging were highly sensitive, accurate, and specific. There was agreement among all readers. Of the 140 datasets reported by each reader, 4 scans were classified as equivocal, requiring more imaging for confident reporting. Conclusion: Single-time-point imaging showed an accuracy comparable to the dual-time-point imaging in diagnosing cardiac transthyretin amyloidosis. This was further validated by agreement among the 3 readers. Early time-point imaging is preferred, and additional delayed imaging can be acquired when the early result is equivocal.