Gendex GXS-700, User Manual

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Image Quality Assurance
Image quality of the GXS-700 sensor depends on several factors:
•
the quality of the X-ray source (kV, focal spot size, distance)
• the alignment of the X-ray source to the anatomic region
•
the applied X-ray dose / exposure time
• the settings of the computer monitor
It is recommended that you establish a procedure for periodic review of the image quality. If
image quality is not satisfactory, or degrading, please check the contributing system parts as
outlined below:
X-ray Dose / Exposure Time Settings
The GXS-700 sensor has been designed to be used with a wide range of dose settings
between 20 uGy and 2,000 uGy, to allow adjustments of the dose to the specific
diagnostic task, and to compensate for under- and over-exposure. As a general
recommendation, start by using dose / exposure time settings recommended by your
X-ray source manufacturer for digital X-ray sensors.
The GXS-700 sensor can be used with much lower dose / exposure time settings.
Nevertheless, low dose operation of a digital sensor in general can result in a grainy
image appearance. If the image of the GXS-700 sensor appears grainy, increase the
dose settings. If you obtain good results with a particular setting, you might try a
lower dose setting to see if you still gain good results.
The GXS-700 sensor can work at higher dose /exposure time settings, if needed for a
particular diagnostic task. At high dose / exposure time settings, it might not be
possible to distinguish air from soft tissue. Such regions may appear overexposed. If
air and soft tissue regions in the image appear overexposed, reduce the dose settings.
Remember, as with standard film, you will need to adjust the duration setting to
compensate for tooth type (central incisor to molar) and patient body type (larger
adult to small child). Ultimately, the settings you choose should be what you consider
to be suitable for your diagnostic needs.
X-ray Sharpness / Contrast
Many parts of the X-ray imaging system contribute to the sharpness and contrast of
the image. It is recommended that you use a dental phantom for a periodic (at least
annual) assessment of the image quality by performing a side-by-side comparison of
an initial dental phantom image to a current dental phantom image to ensure that
the images have sufficient quality for diagnostic purposes in your application.
Dental phantom images should be acquired with fixed settings for X-ray dose (kV,
mA, distance), and a fixed and reproducible alignment of the X-ray source and the
dental phantom to the Gendex GXS-700 sensor.
GXS-700.book Page 7 Wednesday, January 27, 2016 9:58 AM