K Hirano et al 2007 Phys. Med. Biol. 52 2545 doi:10.1088/0031-9155/52/9/014
K Hirano1, T Miyoshi1, N Igarashi1, T Takeda2, J Wu2, T-T Lwin2, M Kubota3, N Egami3, K Tanioka3, T Kawai4 and S Wakatsuki1
Show affiliationsA HDTV camera having a direct-sensing x-ray high-gain avalanche rushing amorphous photoconductor (HARP) tube was used, for the first time, to acquire x-ray phase maps. The tube can achieve a high sensitivity as a result of the avalanche multiplication process in the HARP target. A beryllium plate, rather than a glass plate, was used as the face plate of the tube to minimize the loss of x-rays due to absorption, and a 15 µm thick HARP target was directly formed on it. In the experiment, the x-ray phase shifts produced by a rat liver were measured using synchrotron x-rays (λ = 0.0766 nm) and a triple Laue-case (LLL) x-ray interferometer. Interference patterns produced by the sample were observed with the direct-sensing x-ray HARP tube camera. A voltage of 1300 V was applied to the HARP target to give an output signal gain of two. The camera was operated in 1125 scanning-line mode, and real-time images were stored on a workstation at a rate of 30 images/s with an image format of 960 (H) × 1100 (V) pixels. A phase-map image of the sample was successfully obtained using the fringe scanning method and phase unwrapping. The observed phase shifts ranged from 50° to 200°. Trees of blood vessels in the rat liver were clearly depicted without using a contrast agent. The spatial resolution of the x-ray camera was estimated to be better than 35 µm in the vertical direction and 100 µm in the horizontal direction.
07.85.Fv X- and gamma-ray sources, mirrors, gratings, and detectors
Issue 9 (7 May 2007)
Received 6 November 2006, in final form 7 February 2007
Published 11 April 2007
K Hirano et al 2007 Phys. Med. Biol. 52 2545
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