Journal of nuclear medicine technology最新文献

Diagnostic reference levels (DRLs) are an important tool for controlling radiation exposure and ensuring safety in medical applications. In Thailand, DRL data have been gathered and established for nuclear medicine diagnostics since 2021. However, there is a lack of information on PET imaging examinations. At the National Cyclotron and PET Scan Centre, Chulabhorn Hospital, radiopharmaceuticals are produced for medical imaging and research, and a wide range of PET/CT and PET/MRI examinations are performed. Our objective was to investigate the administered activity of radiopharmaceuticals in patients undergoing PET imaging, especially the existing data on DRLs in medical diagnostic imaging. Methods: This was a retrospective study on nuclear medicine patients at the National Cyclotron and PET Scan Centre in 2023. Statistical analysis, including the mean and the 75th percentile values, was conducted to determine DRLs according to the International Commission on Radiological Protection guidelines. Results: The center performed 8,711 PET/CT and PET/MRI studies with 13 protocols in 2023. The most commonly administered activity was ¹⁸F-FDG in oncology and neurology examinations, with DRLs of 186.11 and 136.16 MBq, respectively. These values were notably almost twice lower than several reports in other countries. Conclusion: There is a lack of comprehensive data on most DRLs for PET imaging at this center because of the nonwidespread use of several radiopharmaceuticals. However, the lower DRLs for ¹⁸F-FDG can highlight the need for ongoing investigation toward the establishment of local DRLs, as well as assurance on the safety and efficiency of radiation used in nuclear medicine.

Brain death denotes the loss of function in both the cerebrum and the brain stem, leading to coma, absence of spontaneous respiration in the setting of adequate stimulus, and the cessation of all brain stem reflexes. Although spinal reflexes such as deep tendon, plantar flexion, and withdrawal reflexes may persist, recovery is not possible. The cessation of brain function qualifies as death because of its central role in coordinating vital bodily functions. Although brain death is largely determined by a clinical and neurologic examination, confounding variables may necessitate ancillary testing such as cerebral brain perfusion imaging.

^99mTc-labeled dimercaptosuccinic acid (^99mTc-DMSA) imaging is a well-established and highly sensitive method for the diagnosis of several renal cortical disorders affecting children and adults. Beginning in 2014, ^99mTc-DMSA availability was severely impaired when it was added to the Drug Shortages List of the U.S. Food and Drug Administration and was commercially unavailable thereafter. The agent shortage negatively impacted practitioners' ability to evaluate renal cortical defects in children and adults and changed renal imaging practice. A survey among pediatric nuclear medicine clinicians confirmed the clinical need for ^99mTc-DMSA. Finally, in early 2023 the Food and Drug Administration again approved ^99mTc-DMSA in the United States. During the ^99mTc-DMSA shortage, established practitioners may not have had the opportunity of using ^99mTc-DMSA as they were accustomed in their experience. Also, newer imaging specialists and referring physicians and technologists may not have benefited from having ^99mTc-DMSA in their training. Therefore, it is time to bring back ^99mTc-DMSA into the armamentarium of imaging methods available to evaluate regional cortical renal function.

Our aim was to develop communication support material for information sharing related to an ¹⁸F-FDG PET/CT examination. Methods: The study had a qualitative design adapting a multiphase structure. A prototype of communication support material consisting of illustrations and text related to an ¹⁸F-FDG PET/CT examination was developed. Interviews were conducted with patients scheduled for an ¹⁸F-FDG PET/CT examination for the first time, and questionnaires were collected from health care professionals with experience in ¹⁸F-FDG PET/CT. The communication support material was revised until consensus was reached about it. Results: The results are based on interviews with patients (n = 10) and questionnaires collected from health care professionals (n = 9). The overall theme revealed that patient information about an ¹⁸F-FDG PET/CT examination is a balancing act between text and illustrations. The analysis showed 2 categories: "illustrations as a complement" and "easy-to-understand layout." Conclusion: The participants strengthened the development of the communication support material by bringing in valuable viewpoints from various perspectives. The results support a person-centered approach in which information about an ¹⁸F-FDG PET/CT examination can be adapted to each patient's needs as a balancing act between text and illustrations.

Hepatic metastases of cranial meningiomas are rare, particularly when they present as a delayed, solitary metastasis, which poses a challenge for imaging-based diagnosis. [¹⁸F]FDG PET/CT facilitates diagnosis and posttreatment restaging, whereas somatostatin receptor-targeted PET demonstrates high sensitivity and specificity in the diagnosis of meningiomas and may potentially evaluate the viability of theranostics approaches, particularly for treatment-resistant meningiomas.

Oncocytic adenomas are rare benign tumors that typically originate in organs such as the kidneys, thyroid, parathyroid, salivary glands, or pituitary gland. Oncocytic adenoma of the adrenal gland is extremely rare. It often shows heterogeneous, nonspecific features on anatomic imaging, as well as high ¹⁸F-FDG avidity despite its benign nature. The definitive diagnosis relies on histopathologic examination, including immunohistochemistry. We present an incidentally detected benign adrenal oncocytic adenoma with intense ¹⁸F-FDG uptake mimicking sinister pathologies.

The combined supine-prone imaging protocol for SPECT myocardial perfusion imaging offers significant advantages over supine imaging alone. By comparing supine and prone images, one can distinguish attenuation artifacts in the inferior and anterior walls from true perfusion defects, thus improving specificity and diagnostic accuracy. The recommended protocol is to perform prone imaging after supine stress imaging when perfusion defects are noted. The additional prone imaging time is 20%-40% less than the standard supine imaging time. Implementing prone imaging can optimize patient care and provide substantial benefits for nuclear cardiology labs, especially those without attenuation correction.

The early years of nuclear medicine included the development and clinical use of several in vitro or nonimaging procedures. The use of radionuclides as replacements for nonradioactive dyes brought improved accuracies and less subjective measurements to indicator dilution studies of body compartments such as the gastrointestinal system, lungs, urinary system, and vascular space. A popular nuclear medicine procedure was the radionuclide dilution method for quantitation of whole-blood volume or red blood cell volume or mass using ⁵¹Cr-labeled red blood cells-an important diagnostic element in patients suspected of having polycythemia vera, congestive heart failure, hypertension, shock, syncope, and other abnormal blood volume disorders. The radionuclide dilution method led to improved evaluation of red blood cell survival, which is important for clinical treatment planning in anemia and confirmation of splenic sequestration of damaged red blood cells. Although it was discovered that ⁵¹Cr was a chemically stable radiolabel of red blood cells after binding to intracellular hemoglobin, few nuclear medicine departments offered the clinical study for referring physicians because it required laboratory expertise for technologists, patient coordination, and a time-consuming procedure. The introduction of improved methods that are less time-consuming and have clinically acceptable results, along with the discontinuation of the sodium chromate ⁵¹Cr injection radiopharmaceutical by manufacturers, has consigned ⁵¹Cr red blood cells for red blood cell volume, mass, or survival evaluation to the list of retired nuclear medicine studies.

Asymmetric hot spots in the axial skeleton on bone scintigraphy may confound diagnosis. We describe an unexpected artifact of ^99mTc-methylene diphosphonate near the breast in a 55-y-old woman with breast cancer. The initial whole-body bone scintigraphy revealed a solitary focal lesion in the anterior ribs on the left side. After careful tracking, we determined that this hot spot originated from the adhesive bandage. The patient had placed it in her left front pocket after removing it from the injection site. She was rescanned after the bandage had been removed from her pocket.