Positron emission tomography (PET) is a powerful non-invasive molecular imaging technique for the early detection, characterization, and "real-time" monitoring of disease, and for investigating the efficacy of drugs (Phelps, 2000; Ametamey et al., 2008). The development of molecular probes bearing short-lived positron-emitting radionuclides, such as ¹⁸F (half-life 110 min) or ¹¹C (half-life 20 min), is crucial for PET imaging to collect in vivo metabolic information in a time-efficient manner (Deng et al., 2019). In this regard, one of the main challenges is rapid synthesis of radiolabeled probes by introducing the radionuclides into pharmaceuticals as soon as possible before injection for a PET scan. Although many potential PET probes have been discovered, only a handful can satisfy the demand for a highly efficient synthesis procedure that achieves radiolabeling and delivery for imaging within 1-2 radioisotope half-lives. Only a few probes, such as 2-deoxy-2-[¹⁸F]fluoro-D-glucose (¹⁸F-FDG) and [¹⁸F]fluorodopa, are routinely produced on a commercial scale for daily clinical diagnosis (Grayson et al., 2018; Carollo et al., 2019).
Lab-On-A-Chip Devices ; Positron-Emission Tomography/methods* ; Radioisotopes/chemistry* ; Radiopharmaceuticals/chemical synthesis* ; Solid Phase Extraction

OBJECTIVETo compare the diagnostic accuracy of (99)Tc(m)-MIBI SPECT/CT and (18)F-FDG coincidence SPECT/CT for solitary pulmonary nodules.

METHODSA total of 88 cases suspected of solitary pulmonary nodules were analyzed retrospectively, of whom 36 were examined with (18)F-FDG coincidence SPECT/CT and 52 with (99)Tc(m)-MIBI SPECT/CT. The nature of the solitary pulmonary nodules (malignant or benign) were determined according to the pathological or follow-up (>2 years) results. The diagnostic accuracy of the two modalities for solitary pulmonary nodules was evaluated by ROC curve. The correlation of the lesion size and pathological grade determined by the two modalities with the L/N ratio was assessed using Spearman correlation analysis.

RESULTS(18)F-FDG coincidence SPECT/CT and (99)Tc(m)-MIBI SPECT/CT showed a similar area under curve (AUC) of the L/N ratio (0.92 vs 0.88, P=0.565) with diagnostic sensitivities of 76.92% (20/26) and 80.77% (21/26) and specificities of 100% (10/10) and 88.46% (23/26), respectively. For solitary pulmonary nodules with lesion diameter ≤2 cm, the AUC was 1.00 with (18)F-FDG coincidence SPECT/CT and 0.90 with (99)Tc(m)-MIBI SPECT/CT (P=0.746), while for nodules beyond 2 cm but below 3 cm, the AUCs were 0.79 and 0.89, respectively (P<0.001). In either of the two modalities, correlation analysis revealed no correlation of the L/N ratio with the pathological grade of the malignant lesions (P=0.771 and 0.077, respectively). The L/N ratio was not correlated with the size of the malignant lesion detected by (99)Tc(m)-MIBI SPECT/CT (P=0.516) but was significantly correlated with the size of the malignant lesions detected by (18)F-FDG coincidence SPECT/CT (P=0.016).

CONCLUSION(99)Tc(m)-MIBI SPECT/CT has a greater diagnostic accuracy than (18)F-FDG coincidence SPECT/CT for solitary pulmonary nodules with lesion a diameter beyond 2 cm, and is therefore the primary choice for low-income patients.

Area Under Curve ; Fluorodeoxyglucose F18 ; chemistry ; Humans ; ROC Curve ; Radiopharmaceuticals ; Retrospective Studies ; Sensitivity and Specificity ; Solitary Pulmonary Nodule ; diagnostic imaging ; Technetium Tc 99m Sestamibi ; chemistry ; Tomography, Emission-Computed, Single-Photon ; Tomography, X-Ray Computed

Standardized uptake value (SUV), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) have been considered prognostic factors for survival in many cancers. However, their prognostic value for radiotherapy-treated squamous esophageal cancer has not been evaluated. In this study, SUV, MTV, and TLG were measured to predict their prognostic role in overall survival (OS) in 38 esophageal cancer patients who had undergone 18F-FDG PET/CT before radiotherapy. TLG demonstrated higher sensitivity and specificity for predicting OS than MTV and SUV; and a better OS was observed in patients with low TLG compared to those with high TLG in locally advanced disease (OS, 46.9 months; 95% confidence interval [CI], 33.50-60.26 vs. 25.3 months; 95% CI, 8.37-42.28; P=0.003). Multivariate analyses in these patients determined that TLG and the use of combination chemotherapy were the independent prognostic factors for OS (hazard ratio [HR], 7.12; 95% CI, 2.038-24.857; P=0.002 and HR, 6.76; 95% CI, 2.149-21.248; P=0.001, respectively). These results suggest that TLG is an independent prognostic factor for OS and a better predictor of survival than MTV and SUV in patients with locally advanced esophageal cancer treated with radiotherapy.
Adult ; Aged ; Aged, 80 and over ; Area Under Curve ; Esophageal Neoplasms/mortality/pathology/*radiography ; Female ; Fluorodeoxyglucose F18/chemistry ; Glycolysis/*physiology ; Humans ; Male ; Middle Aged ; Neoplasm Staging ; *Positron-Emission Tomography ; Prognosis ; Proportional Hazards Models ; ROC Curve ; Radiopharmaceuticals/*chemistry ; Retrospective Studies ; Survival Rate ; *Tomography, X-Ray Computed

Nuclear medicine is a rapidly growing discipline that employs advanced novel hybrid techniques that provide unique anatomical and functional information, as well as targets for molecular therapy. Concomitantly, there has been an increase in the attention paid to medical radiation exposure. A radiological justification for the practice of nuclear medicine has been implemented mainly through referral guidelines based on research results such as prospective randomized clinical trials. The International Commission on Radiological Protection recommends diagnostic reference levels as a practical mechanism to optimize medical radiation exposure in order to be commensurate with the medical purpose. The Korean Society of Nuclear Medicine has been implementing radiological optimization through a survey of the protocols on how each hospital determines the dose of administration of each radiopharmaceutical. In the case of nuclear medicine, radiation exposure of caregivers and comforters of patients discharged after administration of therapeutic radiopharmaceuticals can occur; therefore, optimization has been implemented through written instructions for patients, based on international recommendations. The development of patient-radiation-dose monitoring software, and a national registry and management system of patient-radiation-dose is needed to implement radiological optimization through diagnostic reference levels. This management system must work in agreement with the "Institute for Quality Management of Nuclear Medicine", and must take into account the medical reality of Korea, such as low medicine fee, in order to implement reasonable radiological justification and optimization.
Humans ; Neoplasms/diagnosis/radiotherapy ; Positron-Emission Tomography ; *Practice Guidelines as Topic ; Radiation Exposure/*standards ; Radiation Protection ; Radiopharmaceuticals/chemistry/therapeutic use ; Reference Values ; Republic of Korea ; Societies, Scientific ; Tomography, X-Ray Computed

We report a rare case of primary pulmonary low-grade angiosarcoma on dynamic contrast-enhanced CT and 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT imaging. A 38-year-old, asymptomatic woman was hospitalized because of an abnormality on chest radiography. A dynamic contrast-enhanced chest CT showed a 1.2 cm-sized irregular-margined nodule with strong and persistent enhancement in the right lower lobe. The lesion had low metabolic activity on an 18F-FDG PET/CT scan. The patient underwent a wedge resection for the lesion, and pathology revealed a primary pulmonary low-grade angiosarcoma.
Adult ; Female ; Fluorodeoxyglucose F18/*chemistry ; Hemangiosarcoma/*diagnosis/pathology/radiography ; Humans ; Ki-67 Antigen/metabolism ; Lung Neoplasms/*diagnosis/pathology/radiography ; Multimodal Imaging ; *Positron-Emission Tomography ; Radiopharmaceuticals/*chemistry ; Tomography, Spiral Computed

OBJECTIVE: In this study, there was an investigation as to whether there is a functional difference in essential tremor (ET), according to responses to beta-blockers, by evaluating regional changes in cerebral glucose metabolism. MATERIALS AND METHODS: Seventeen male patients with ET were recruited and categorized into two groups: 8 that responded to medical therapy (group A); and 9 that did not respond to medical therapy (group B). Eleven age-sex matched healthy control male subjects were also included in this study. All subjects underwent F-18 fluorodeoxyglucose (FDG)-PET, and evaluated for their severity of tremor symptoms, which were measured as a score on the Fahn-Tolosa-Marin tremor rating scale (FTM). The FDG-PET images were analyzed using a statistical parametric mapping program. RESULTS: The mean FTM score 6 months after the initiation of propranolol therapy was significantly lower in group A (18.13 > 8.13), compared with group B (14.67 = 14.67). The glucose metabolism in group A in the left basal ganglia was seen to be decreased, compared with group B. The ET showed a more significantly decreased glucose metabolism in both the fronto-temporo-occipital lobes, precuneus of right parietal lobe, and both cerebellums compared with the healthy controls. CONCLUSION: Essential tremor is caused by electrophysiological disturbances within the cortical-cerebellar networks and degenerative process of the cerebellum. Furthermore, ET may have different pathophysiologies in terms of the origin of disease according to the response to first-line therapy.
Adrenergic beta-Antagonists/*pharmacology/therapeutic use ; Aged ; Brain/*drug effects/metabolism/radiography ; Brain Mapping ; Essential Tremor/*diagnosis/drug therapy/radiography ; Fluorodeoxyglucose F18/*chemistry ; Glucose/*metabolism ; Humans ; Male ; Middle Aged ; *Positron-Emission Tomography ; Propranolol/pharmacology/therapeutic use ; Radiopharmaceuticals/*chemistry

Whole body integrated magnetic resonance imaging (MR)/positron emission tomography (PET) imaging systems have recently become available for clinical use and are currently being used to explore whether the combined anatomic and functional capabilities of MR imaging and the metabolic information of PET provide new insight into disease phenotypes and biology, and provide a better assessment of oncologic diseases at a lower radiation dose than a CT. This review provides an overview of the technical background of combined MR/PET systems, a discussion of the potential advantages and technical challenges of hybrid MR/PET instrumentation, as well as collection of possible solutions. Various early clinical applications of integrated MR/PET are also addressed. Finally, the workflow issues of integrated MR/PET, including maximizing diagnostic information while minimizing acquisition time are discussed.
Coordination Complexes/chemistry/diagnostic use ; Heart/radiography ; Humans ; *Magnetic Resonance Imaging ; Neoplasm Metastasis ; Neoplasm Staging ; Neoplasms/pathology/radiography ; *Positron-Emission Tomography ; Radiopharmaceuticals/diagnostic use ; Tomography, X-Ray Computed ; Whole Body Imaging/*standards/*trends

Colloidal particle size is an important characteristic that allows mapping sentinel nodes in lymphoscintigraphy. This investigation aimed to introduce different ways of making a 99mTc-tin colloid with a size of tens of nanometers. All agents, tin fluoride, sodium fluoride, poloxamer-188, and polyvinylpyrrolidone (PVP), were mixed and labeled with 99mTc. Either phosphate or sodium bicarbonate buffers were used to adjust the pH levels. When the buffers were added, the size of the colloids increased. However, as the PVP continued to increase, the size of the colloids was controlled to within tens of nanometers. In all samples, phosphate buffer added PVP (30 mg) stabilized tin colloid (99mTc-PPTC-30) and sodium bicarbonate solution added PVP (50 mg) stabilized tin colloid (99mTc-BPTC-50) were chosen for in vitro and in vivo studies. 99mTc-BPTC-50 (<20 nm) was primarily located in bone marrow and was then secreted through the kidneys, and 99mTc-PPTC-30 (>100 nm) mainly accumulated in the liver. When a rabbit was given a toe injection, the node uptake of 99mTc-PPTC-30 decreased over time, while 99mTc-BPTC-50 increased. Therefore, 99mTc-BPTC-50 could be a good candidate radiopharmaceutical for sentinel node detection. The significance of this study is that nano-sized tin colloid can be made very easily and quickly by PVP.
Animals ; Buffers ; Cell Line, Tumor ; Humans ; Lymph Nodes/*radionuclide imaging ; Lymphatic Metastasis ; Metal Nanoparticles/chemistry/ultrastructure ; Mice ; Neoplasms, Experimental/*radionuclide imaging ; Particle Size ; Povidone/*chemistry ; Rabbits ; Radiopharmaceuticals/*chemical synthesis ; Reproducibility of Results ; Sensitivity and Specificity ; Technetium Compounds/*chemistry ; Tin/*chemistry ; Tin Compounds/*chemistry

OBJECTIVETo establish a labeling method for a specific lung cancer-targeting small molecule peptide cNGQGEQc with ¹³¹I and observe the radioactivity distribution of the labeled peptide in rabbits using single-photon emission computed tomography (SPECT).

METHODSChloramine-T method was used for ¹³¹I labeling of the tyrosine amino group on cNGQGEQc, and the labeling efficiency and radiochemical purity of ¹³¹I-cNGQGEQc were determined with paper chromatography. The stability of ¹³¹I-cNGQGEQc in saline and human serum was assessed after incubation in water bath at 37 degrees celsius; for 24 h. The octanol-water partition coefficient lg P (the radioactivity counting ratio of ¹³¹I-cNGQGEQc dissolved in 100 µl octanol or in 100 µl saline) was calculated. SPECT was performed in 3 male New Zealand white rabbits after intravenous injection of ¹³¹I-cNGQGEQc to observe the dynamic distribution of the peptide with the time-radioactivity curve (T-A curve) of the region of interest (ROI).

RESULTSWith a labeling efficiency of 90%, ¹³¹I-cNGQGEQc showed a radiochemical purity of was 95% after purification with HPLC. The radiochemical purity of ¹³¹I-cNGQGEQc was (93.12 ± 1.18)% and (88.34 ± 5.43)% after intubation in saline and human serum for 24 h, respectively. The octanol-water partition coefficient lg P of ¹³¹I-cNGQGEQc was -1.75, suggesting its hydrosolubility. In rabbits with intravenous injection of ¹³¹I-cNGQGEQc, SPECT visualized the kidneys at 1 min after the injection; the imaging of the heart and liver became attenuated at 5 min when the bladder was visualized with an increasing radioactivity. The radioactivity of the soft tissues began to fade at 30 min. No gallbladder visualization was detected, and the radioactivity of the abdomen remained low. No obvious radioactivity concentration was observed in the thyroid and stomach. The T-A curves of the ROI of all the tissues and organs descended over time.

CONCLUSIONRadiolabeling of cNGQGEQc with ¹³¹I is simple and highly efficient. ¹³¹I-cNGQGEQc has good stability in vitro and good distribution characteristics for in vivo imaging, and is cleared mainly by renal excretion due to its hydrosolubility. These results provide experimental basis for further studies of diagnosis and therapy of lung cancer with targeting polypeptide.

Animals ; Antineoplastic Agents ; pharmacokinetics ; Chloramines ; Humans ; Iodine Radioisotopes ; chemistry ; Lung Neoplasms ; Male ; Peptides ; pharmacokinetics ; Rabbits ; Radiopharmaceuticals ; pharmacokinetics ; Tissue Distribution ; Tomography, Emission-Computed, Single-Photon ; Tosyl Compounds

Transcatheter arterial radioembolization (TARE) with Yttrium-90 (90Y)-labeled microspheres has an emerging role in treatment of patients with unresectable hepatocellular carcinoma. Although complication of TARE can be minimized by aggressive pre-evaluation angiography and preventive coiling of aberrant vessels, radioembolization-induced gastroduodenal ulcer can be irreversible and can be life-threatening. Treatment of radioembolization-induced gastric ulcer is challenging because there is a few reported cases and no consensus for management. We report a case of severe gastric ulceration with bleeding that eventually required surgery due to aberrant deposition of microspheres after TARE.
Aged ; Carcinoma, Hepatocellular/*diagnosis/radiotherapy ; Embolization, Therapeutic/*adverse effects ; Gastrectomy ; Gastrointestinal Hemorrhage/etiology ; Gastroscopy ; Humans ; Liver Neoplasms/*diagnosis/radiotherapy ; Magnetic Resonance Imaging ; Male ; *Microspheres ; Radiopharmaceuticals/therapeutic use ; Stomach/pathology ; Stomach Ulcer/*etiology/surgery ; Yttrium Radioisotopes/chemistry