Overview of X-Ray
X-ray is a kind of electromagnetic radiation
- Wavelength 10-9 ~ 10-12 m
- 1876 : Cathode ray observed
- 1887 : Bremsstrahlung effect X-ray tube developed (N. Tesla)
- 1892 : Penetration effect discovered (H.R. Hertz)
- 1895 : The ¡®unknown¡¯ radiation named as X-ray (Roentgen)
- 1896 : Medical X-ray equipment developed (Edison)
- 1971 : CT scanner invented (Hounsfield)
- 1980 : First digital X-ray image
Direct type of X-ray Detector
Detector technology is, what they call, the future of the X-ray detector technology. It has many advantages over indirect type X-ray detector technology.
Sensor directly converts X-rays to electronic signal, unlike any other indirect X-ray detector using scintillator and CMOS sensor. Indirect type X-ray detector converts X-ray into light and then takes image using photo diode(CMOS or CCD sensor). The light scatters and goes extinct as it passes through sintillator and before it reaches to the CCD or CMOS sensor. But, unlikely indirect type detector,
Sensor directly converts X-rays to electronic signals. X-rays are not converted to light, therefore no blurring occurs and it provides much sharper images and better contrast than indirect type detector. In addition to that high DQE(Direct Quant§ Efficiency) of sensor enables high performance at lower dose of X-ray.
Merit of direct type
- Normal X-ray detectors using the type of indirect Scintillator that read to method of electrical signals by using photo-diode after changing visible light to X-ray. However, this type has no option but to block signal scattering and extinction while on transmission process of multi-step, In conclusion, it happen the problem of falling absorption efficiency and poor spatial resolution of the image.
- detector using the type of direct that X-ray photon is converted into an electrical signal directly from a . In conclusion, it has the superior efficiency and the advantage of spatial resolution.
- Medical/Dental X-ray imaging device
- Scientific X-ray imaging
- Non-distructive Test(NDT)