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BACKGROUND AND PURPOSE: Conventional MR imaging techniques cannot produce optimal images of bone structures because bone has little water and a very short T2 life span. The aim of this study was to investigate the clinical feasibility of skull MR imaging using the zero TE sequence in patients with head trauma by assessing its diagnostic image quality and quantitative measurement compared with CT images. MATERIALS AND METHODS: Thirteen enrolled patients with head trauma were assessed using brain CT and skull MR imaging. Image quality was graded on a 5-point Likert scale to compare the 2 modalities. To evaluate quantitative analyses between the 2 imaging modalities, we measured skull thickness and normalized bone tissue signal. Interobserver reliability was assessed using weighted κ statistics and the intraclass correlation coefficient. RESULTS: Both imaging techniques clearly depicted skull fractures in all 13 patients. The mean scores for skull MR imaging and CT were 4.65 ± 0.56 and 4.73 ± 0.45 (P = .157), respectively, with substantial interobserver agreement (P < .05). The 2 imaging modalities showed no difference in skull thickness (P = .092) and had good correlation (r(2) = 0.997). The mean value of normalized bone tissue signal among the 3 layers of the skull was relatively consistent (P = .401) with high interobserver agreement (P < .001). CONCLUSIONS: Zero TE skull MR imaging has diagnostic image quality comparable with that of CT images. It also provides consistent results on the quantitative measurement of cortical bone with CT images.

We have been developing a mine detection system coupled with a 1 MV compact tandem accelerator. This system will consist of a compact high current tandem accelerator, a target system, a detection system, a power generator system and a transportation system for mine field applications. The tandem accelerator is designed to accelerate protons with energies of 1.75 MeV up to a 10 mA beam current. We have developed a new mine detection method for a scattered 9.17 MeV gamma-ray produced from the /sup 14/N(/spl gamma/,/spl gamma/)/sup 14/N photo-resonant reaction. The incident gamma-rays are produced by a 1.75 MeV proton beam bombarding at a /sup 13/C target. A new detection method is described which separates the scattered gamma-rays from the /sup 13/C target gamma-rays to within a 0.1% energy resolution using the Doppler effect from the nucleus recoil mechanism.

A new scheme for beam extraction is presented to partially extract a negative hydrogen ion beam at 260 MeV from the main linac where both protons and negative hydrogen ions are accelerated up to 1 GeV. The negative hydrogen ions are extracted by a stripper magnet and the un-extracted ions are returned to the linac. The main feature of this extractor is its ability to regulate the intensity of the extracted beam with the stripper magnet. This extraction scheme will be utilized for the KOMAC (Korea Multi-purpose Accelerator Complex) linear accelerator of 1 GeV cw proton (H/sup +/)/negative-hydrogen (H/sup -/) beams with an intensity of 20 mA.