X-ray phase imaging of biological soft tissue using a direct-sensing x-ray HARP tube camera.
A 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 microm 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 (lambda = 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) x 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 degrees to 200 degrees . 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 microm in the vertical direction and 100 microm in the horizontal direction.
Hirano
K
K
Photon Factory, National Laboratory for High Energy Physics, 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan. keiichi.hirano@kek.jp
Miyoshi
T
T
Igarashi
N
N
Takeda
T
T
Wu
J
J
Lwin
T-T
TT
Kubota
M
M
Egami
N
N
Tanioka
K
K
Kawai
T
T
Wakatsuki
S
S
D000818:Animals; D008099:Liver / Q000098:blood supply / Q000000981:diagnostic imaging*; D011856:Radiographic Image Enhancement; D011859:Radiography / Q000295:instrumentation; D051381:Rats; D017356:Synchrotrons