2. Processor sensitometry (CR , DR don’t have any standardized guidelines yet )
3. Darkroom and Screen cleanliness
4. Safelight testing, Film-screen contact
5. Viewboxes & viewing conditions
6. Repeat analysis (Reject analysis for CR,DR )
7. Other tests by needs or specific areas
( mammo, etc )
While the manufacturer will also normally do this testing on new equipment, the facility must do all QC tests independent of the manufacturer to be sure that they are being honest and the equipment meets all State/National legal requirements!
Sensitometer (greater consistency) vs Step-wedge/Penetrometer (requires use of same cassette, generator/tube, technique factors)
One box of film set aside for processor QC and used only for that purpose until finished
Daily Plotting of results (1) Fog/Background index (clear area of film) (2) Speed index (3) Contrast index
2) Speed Index
3) Contrast Index
Plots of film density (log of opacity) versus the log of exposure
B. Contrast Index
C. Base + Fog
Processing Chemicals –
Processor Cleaning –
If one doesn’t know why films are being repeated(faulty equipment, misunderstanding of dept exam protocols, sloppy positioning practices, etc…), there is less chance that improvements will be made or implemented.
While technique errors with digital systems will be relatively minimal, knowing what errors are leading to the majority of repeat radiographs will improve RT quality and decrease pt. exposure levels as well.
2. check x-ray field, light beam congruence
4. SID Indicators
5. Centuring Accuracy
Misalignment of the collimated light field with the actual x-ray field may result in missed 1. ________ or ________. Semi-annual 8 coin test may 2. __________________ which must not exceed 3. ________ of the SID utilized.
4. _________ must test accurate to plus or minus 2% of the SID being used and
5. ________ must be to within 1 % of the SID. Some States require PBL (positive beam limita-tion)(the x-ray beam can be no larger than the image receptor except in the override mode).
<0.8mm = ± 50%; 0.8-1.5 mm = ± 40%; > 1.5 mm = ± 30%
(50% commonly used as maximum value).
*What is Pinhole Camera?*
*What is Star Test Patter?*
*What is Multiple Bar Pattern?*
*What is Slit Camera?*
Annual testing of exposure timer accuracy must be within…?
Expensive, but provides digital readout and can be shown as time or pulses.
How is Newer testing done?
What is Spinning Top (Manual)
2. Pt. dose
Proper kVp calibration is important since this factor is set by the RT for every x-ray exam. Variations in kVp not only affect beam 1. ________ & ________ but also produce changes in 2. _______. Most physicists use filtered ion chambers or filtered photodiodes for kVp testing. 3. ________ can be used and are very accurate but require long set-up times.
*Older kVp test cassettes (Ardran-Crookes or Wisconsin test cassettes) are rarely used today. Accuracy: Mammo ± 1 kVp; Diagnostic ± 4-5 kVp or 10% of set kVp value*
3. 4 step-wedge
Also known as mA or mAs linearity. Annual test commonly uses a 1. _______ _______ to measure different mA stations at a constant time setting to check radiographic output. Must be accurate to ± 2. _______% among adjacent mA stations. Checked after time settings are found to be accurate.
Older method used 3. ___ _____-______ exposures on cassette at different mA stations & compensated time settings to produce the same mAs. Density of the same step on all 4 exposures checked for 4.__________.
*This test is really measuring mAs reciprocity – any mA & time that produce the same mAs, should produce the same density*
3. using an ionization chamber type meter or digital dosimeter
4. Erratic output
This test measures the x-ray machines ability to produce the same 1. _________ _______ using the same exposure factors after being reset from a prior exposure at the same setting.
This should be done annually and may vary by ± 2. __________. 3-10 exposure are made at a given technique setting 3. _____________________ to measure actual tube output in (R) or (mR/mAs or R/100mAs). Technique setting may be used that RT’s have reported as having 4.__________ if appropriate.
*This test requires great accuracy because it is measuring actual pt. exposure levels!*
Filtration/Beam Quality/ HVL