Hologic Faxitron Path - Definitions; Periodic Maintenance

FAXITRON PATH USER MANUAL | HOLOGIC | REVISION 024
S
ECTION
S
chedule of
Maintenance
8
8 - 3
The following definitions apply for the terms listed below when referenced in this Schedule o
f
Maintenance.
ACR Phantom- American College of Radiology Accreditation Phantom.
ADU- Analog-to-Digital Units.
AEC- Automatic Exposure Control - Computer terminates x-rays when enough signal has
reached the detector.
Contrast: Percent of difference between object intensity and background intensity.
Dark current: Thermally generated signal in the sensor; (almost) linear with time.
Flat-fielding: Gain and offset corrections performed on a pixel-by-pixel basis. Each pixel has
a different gain and offset and must be calibrated out.
Line pairs per millimeter: Number of alternating lead and air pieces. For example 10 lp/mm
means => {air/lead} {air/lead} … 10 times in one millimeter.
Magnification: Moving the object away from the detector and towards the x-ray source to
magnify the image of the object on the detector.
MTF: Modulation Transfer Function. A measurement of the contrast and resolution of an
imaging system.
Read noise: RMS noise measurement in 0-second dark exposure (no signal).
ROI: Region Of Interest. Generally a specific sub-region of an image.
SID: Source-to-image distance; distance from the x-ray source to the detector.
Specimen Radiography: X-ray imaging of a piece of tissue after it is extracted from
the body.
8.6.0
Definitions
Periodic maintenance should be performed annually to ensure your Faxitron Path system
continues to perform optimally over time. This periodic maintenance includes verification of the
following:
 Safety Interlocks and Indicators, Section 8.8.0,
 ACR Phantom Test (verifies camera performance), Section 8.8.1, and
 Radiographic Survey, Section 8.8.2.
We recommend these procedures be performed annually, however government regulations
may require more frequent maintenance schedules.
8.7.0
Periodic
Maintenance