S-Space College of Medicine/School of Medicine (의과대학/대학원) Dept. of Medicine (의학과) The Seoul Journal of Medicine The Seoul Journal of Medicine Vol. 28 No.3 (1987)
A Linear Scanning Digital Radiographic System for Chest lmaging
- Park, Kwang Suk; Min, Byoung Goo
- Issue Date
- Seoul J Med, Vol.28 No.3, pp. 263-267
- A linear scanning digital radiographic system was developed using photodiode
array as a detector. Images are collected using this linear photodiode array sensor of 1024
pixels after X-ray photons are converted to light photons by the image intensifying screen.
Sensitive area of each photodiode cell of a linear array sensor is 0.63 mm by 1.3 mm. This
linear array sensor scans with 0.65 mm increments along the scanning axis using a DC servo
motor to form 1024 lines of image within 0.7 sec of scanning time.
A fore-slit, located between the X-ray tube and the patient, converts an area beam to a fan
beam and reduces the patient exposure and scattering effect. Also, this fore-slit scans syncronously
with the detector assembly. Detected electrical signals are integrated to enhance the
efficiency of X-ray exposure and multiplexed to four serial streams representing detected
values of linear array. Then, it is calibrated to compensate for X-ray fluctuation, uneven
sensitivity and bias of each pixel. Collected images are ND converted with 12 bit resolution,
transferred to the computer and displayed on a high resolution monitor.
Images can be processed by the image processing algorithms and all parts of the system are
controlled by the computer. And, images are effectively compressed for storage and transmission
via the local area network in the department of radiology and to clinical wards.