Chul-Woo Joh

Abnormal bone scan in an adult with osteopoikilosis

AbstractOsteopoikilosis is rare, autosomal dominant bone disorder diagnosed by radiologic features. The findings include multiple small, circumscribed round areas of increased bone density distributed symmetrically in a periarticular location. The lesions cluster at the ends of long bones, around th

The effect of external electron beam on neointima in rat carotid artery injury model

PURPOSE Endovascular irradiation with either a gamma or a beta source has shown to reduce neointimal proliferation. However, the effect of external-beam radiation on neointimal hyperplasia is controversial. The objective of this study was to determine the effect of external-beam irradiation with different doses on neointimal hyperplasia in the rat carotid artery injury model. METHODS AND MATERIALS Twenty-seven Sprague-Dawley rats underwent endothelial denudation injury by 2F Fogarty balloons on carotid artery. Immediately after the injury, rats were irradiated externally using 6-MeV electrons. Rats were grouped according to the radiation doses, 0 Gy as controls (n = 5), 5 Gy (n = 5), 10 Gy (n = 5), 15 Gy (n = 6), and 20 Gy (n = 6). Then, rats were sacrificed after 2 weeks and the carotid arteries were perfusion-fixed in paraformaldehyde. External elastic lamina (EEL) area, lumen area, maximal intimal thickness (MIT), and intimal area (IA) of the injured segments were measured on the basis of histomorphometry. RESULTS In EEL and lumen area, there was no statistically significant difference between the irradiated groups and the controls. In MIT and IA, low-dose radiation (5 Gy and 10 Gy) did not induce any significant reduction. High-dose radiation (15 Gy and 20 Gy), however, reduced MIT and IA significantly. CONCLUSION External electron beam reduced the intimal area, and the inhibition of neointimal proliferation was dependent upon radiation doses. This study suggests that the minimal effective dose for the inhibition of neointimal hyperplasia following denudation injury in the rat carotid model is between 10 Gy and 15 Gy.

False negative F-18 FDG PET/CT in nonsmall cell lung cancer bone metastases.

Tc-99m MDP bone scintigraphy is frequently performed for suspected skeletal metastases in lung cancer. F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) has also proved useful for staging nonsmall cell lungcancer, and it offers superior spatial resolution and improved specificity for bone metastases. Although F-18 FDG-PET is superior to Tc-99m MDP bone scintigraphy for the detection of bone metastases, the sensitivity for sclerotic (osteoblastic) metastases by F-18 FDG PET/CT is lower than for lytic metastases. These bone metastases may not be glycolytically active and may be below the requisite tumor mass needed for FDG accumulation. We describe the case of false-negative F-18 FDG PET/CT findings in a 57-year-old woman who demonstrated sclerotic bone metastases from nonsmall cell lung cancer. F-18 fluoride PET demonstrates a similar uptake pattern as Tc-99m MDP.