Pawana Pusuwan

Normal Solid Gastric Emptying Values Measured by Scintigraphy Using Asian-style Meal:A Multicenter Study in Healthy Volunteers.

Background/Aims To report gastric emptying scintigraphy, normal values should be established for a specific protocol. The aim of this study was to provide normal gastric emptying values and determine factors affecting gastric emptying using Asian rice-based meal in healthy volunteers. Methods One hundred and ninety-two healthy volunteers were included at 7 tertiary care centers across Thailand. Gastric emptying scintigraphy was acquired in 45 degree left anterior oblique view immediately after ingestion of a 267 kcal steamed-rice with technetium-99m labeled-microwaved egg meal with 100 mL water for up to 4 hours. Results One hundred and eighty-nine volunteers (99 females, age 43 ± 14 years) completed the study. The medians (5–95th percentiles) of lag time, gastric emptying half time (GE T1/2) and percent gastric retentions at 2 and 4 hours for all volunteers were 18.6 (0.5–39.1) minutes, 68.7 (45.1–107.8) minutes, 16.3% (2.7–49.8%) and 1.1% (0.2–8.8%), respectively. Female volunteers had significantly slower gastric emptying compared to male (GE T1/2, 74 [48–115] minutes vs. 63 (41–96) minutes; P < 0.05). Female volunteers who were in luteal phase of menstrual cycle had significantly slower gastric emptying compared to those in follicular phase or menopausal status (GE T1/2, 85 [66–102] mintes vs. 69 [50–120] minutes or 72 [47–109] minutes, P < 0.05). All of smoking volunteers were male. Smoker male volunteers had significantly faster gastric emptying compared to non-smoker males (GE T1/2, 56 [44–80] minutes vs. 67 [44–100] minutes, P < 0.05). Age, body mass index and alcohol consumption habits did not affect gastric emptying values. Conclusions A steamed-rice with microwaved egg meal was well tolerated by healthy volunteers. Gender, menstrual status and smoking status were found to affect solid gastric emptying.

Ectopic Parathyroid Imaging With Tc-99m Sestamibi

A patient with persistent hypercalcemia after failed parathyroldectomy was referred for localization of an abnormal parathyroid gland. Tc-99m sestamibi imaging revealed a focal area of increased uptake Involving the left anterior mediastinum, suggesting an ectopic parathyroid gland. The pathologic finding showed an ectopic parathyroid adenoma.

Optimization and evaluation of reconstruction-based compensation methods and reconstruction parameters for Tc-99m MIBI parathyroid SPECT

The value of Tc-99m MIBI parathyroid SPECT for localizing parathyroid hyperplasia in chronic renal failure patients remains inconclusive due to limited image quality. Advanced reconstruction methods to improve image quality have been developed but require optimization and evaluation. The goal of this study was to optimize and evaluate compensation methods and reconstruction parameters for Tc-99m MIBI parathyroid SPECT. A phantom population and projection data that modelled clinically realistic variations found in patients were simulated. The 3D OS-EM reconstruction with compensation for attenuation, detector response and scatter in various combinations were studied. For each compensation, the number of updates for OS-EM and the cutoff frequency of a 3D Butterworth filter were optimized and evaluated using anthropomorphic model observer. With optimal parameters, the method with compensation for attenuation and detector response, with or without the addition of scatter compensation, provided the highest lesion detectability for Tc-99m MIBI parathyroid SPECT.

Imaging of A Single Malignant Osseous Involvement by F-18 NaF PET/CT

Since the introduction of Tc-99m methylene diphosphonate (Tc-99m MDP) for bone imaging in 1971 by Subramanian and McAfee, bone scans have become one of the most widely used investigations in nuclear medicine for malignant osseous involvement. After its introduction by Blau et al in 1962, F-18 NaF was recognized as an excellent radiopharmaceutical for skeletal imaging, several decades before the introduction of the PET system.