Basic anatomy Views -importance and positioning Interpretation Skull radiography
Basic quality control tests in medical radiography
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Transcript of Basic quality control tests in medical radiography
Basic quality control tests in medical radiography
Finals Topics
-DARKROOM QUALITY CONTROL
-QUALITY CONTROL FOR X-RAY EQUIPMENT AND ACCESSORIES
DARKROOM QUALITY CONTROL
FilmsDetermination of the Optimum Developing
TimeCheck for the consistency of the
generator outputCheck for mAs linearityCheck for Timer Accuracy
QUALITY CONTROL FOR X-RAY EQUIPMENT AND ACCESSORIES
Collimator CheckCheck for Alignment of the X-ray Tube
Column and the X-ray TableTest for GridsTest for Bucky MovementTest for Lead Rubber Aprons and Gloves
DARKROOM QC
FILMS
Checking for: - Expiry date * “FIFO” method should be observed
- Storage conditions * temperature at about 20-25 C * away from sources of heat and where chemical vapors may leak and fog the film * boxes of films should not be stored on the floor; should be stacked vertically to avoid pressure marks
DARKROOM QC
DETERMINATION OF THE OPTIMUM DEVELOPING TIME
Objective - To determine the developing time that will give the film’s
maximum density without an increase in base + fog.Procedure - Expose the loaded cassette in strips (6 strips) using the lowest
kVp and mAs setting at 100cm SID. The exposure factors may be adjusted until we are able to produce a density of 1.0 on the middle strip. The last strip is not exposed to radiation.
5 exposures
4 exposures
3 exposures
2 exposures
1 exposure
No exposure
PRODUCTION OF SENSITOMETRIC STRIPSX-ray film
Lead sheet
Cut into a number of strips
DARKROOM QC
DETERMINATION OF THE OPTIMUM DEVELOPING TIMEProcedure - Inside the darkroom, cut the film into strips and process them
using different developing times, e.g. 30s, 60s, 90s, 120s, 150s & 180s.
DARKROOM QC
DETERMINATION OF THE OPTIMUM DEVELOPING TIME
Evaluation - Examine the film strips, look at the middle step and determine which strip exhibit the maximum density at an acceptable basic fog. The time used to develop this strip is considered the optimum developing time.
1(30s)
2(60s)
3(90s)
4(120s)
5(150s)
6(180s)
QC FOR X-RAY EQUIPMENT AND ACCESSORIES
CHECK FOR THE CONSISTENCY OF THE GENERATOR OUTPUT
Objective - To determine whether the generator produces the same
density every time the same exposure factors are selected.Procedure - Position the water phantom on the loaded cassette and expose
the film with set factors. Process the film the usual way.
QC FOR X-RAY EQUIPMENT AND ACCESSORIES
CHECK FOR THE CONSISTENCY OF THE GENERATOR OUTPUT
10cm H2O
Exposure 1
10cm H2O
Exposure 2
10cm H2O 10cm H2O
Exposure 1 Exposure 2A. Consistent generator output B. Inconsistent generator output
QC FOR X-RAY EQUIPMENT AND ACCESSORIES
CHECK FOR mAs LINEARITY
Objective - To determine any differences in photographic density when
different mA settings are used for equal mAs value.Procedure - Position the water phantom on the loaded cassette and expose
the film with set factors. Process the film the usual way.
QC FOR X-RAY EQUIPMENT AND ACCESSORIES
CHECK FOR mAs LINEARITY
10cm H2O
Exposure 150mA & 0.2s
10cm H2O 10cm H2O
Exposure 3200mA & 0.05s
Exposure 2100mA & 0.1s
GoodLinearity
QC FOR X-RAY EQUIPMENT AND ACCESSORIES
CHECK FOR mAs LINEARITY
10cm H2O
Exposure 150mA & 0.2s
10cm H2O 10cm H2O
Exposure 3200mA & 0.05s
Exposure 2100mA & 0.1s
PoorLinearity
QC FOR X-RAY EQUIPMENT AND ACCESSORIES
CHECK FOR TIMER ACCURACY
Objective - To determine the accuracy of the x-ray timer.Procedure - Position the spinning top on the loaded cassette and expose
the film using the clinically used exposure times. Process the film the usual way.
QC FOR X-RAY EQUIPMENT AND ACCESSORIES
CHECK FOR TIMER ACCURACY
QC FOR X-RAY EQUIPMENT AND ACCESSORIES
CHECK FOR TIMER ACCURACY For mains supply with 60Hz frequency:
1. One-pulse (self rectified) unit Set time (sec) No. of dots 0.05 3 0.10 6 0.50 30 1.00 602. Two-pulse (full wave rectified) unit Set time (sec) No. of dots 0.05 6 0.10 12 0.50 60 1.00 120
QC FOR X-RAY EQUIPMENT AND ACCESSORIES
COLLIMATOR CHECK
Objective - To check if the radiation field is the same as the area illuminated by the light from the collimator.Procedure - Center the loaded cassette in the useful beam at a commonly
used SID. Collimate the field to approximately half the film’s size and place a metal marker at the center of the illuminated area and mark the inside edges with lead wires. Make an exposure using appropriate technique factors. Make a second exposure with the collimator fully opened. Process the film the usual way.
QC FOR X-RAY EQUIPMENT AND ACCESSORIES
COLLIMATOR CHECK
1st exposure
2nd exposure
QC FOR X-RAY EQUIPMENT AND ACCESSORIES
COLLIMATOR CHECK
Radiation field
Light field
The misalignment should not exceed 2% of the SID
QC FOR X-RAY EQUIPMENT AND ACCESSORIES
CHECK FOR THE ALIGNMENT OF THE X-RAY TUBE COLUMN AND THE X-RAY TABLE• Check for table alignment with the x-ray beam
QC FOR X-RAY EQUIPMENT AND ACCESSORIES
CHECK FOR THE ALIGNMENT OF THE X-RAY TUBE COLUMN AND THE X-RAY TABLE
• Check whether the column is vertical - Using a plumb bob, hold the string’s end against the tube column making sure that the string hangs unobstructed. If the column is parallel to the string, the column is vertical.• Check whether the table top is horizontal - Place a bowl of water on top of the table at different locations and measure the depth of water around the edge of the bowl. If the table is horizontal, the depth of the water will not vary across the bowl.• Check whether the horizontal arm is still horizontal - Measure the distance between the cross-arm and the table top in front of the cross-arm and from the back. The arm is horizontal if the distance is the same from both ends.
QC FOR X-RAY EQUIPMENT AND ACCESSORIES
TEST FOR GRIDS
Objective - To check whether the grid gives a uniform density over its area.Procedure - Place the loaded cassette on the cassette tray or under the
loose stationary grid. Place metal markers on the cassette to indicate the position of the grid on the film. Expose the film using the recommended SID and process the film the usual way.
QC FOR X-RAY EQUIPMENT AND ACCESSORIES
TEST FOR BUCKY MOVEMENT
Objective - To check whether the grid bucky is moving throughout the whole exposure.Procedure - Place the loaded cassette on the cassette tray. Place metal
markers on the cassette to indicate the position of the grid on the film. Expose the film in the bucky mode and process the film the usual way. Check for presence of grid lines on the radiograph.
QC FOR X-RAY EQUIPMENT AND ACCESSORIES
LEAD RUBBER APRONS AND GLOVESCare -clean with soap and water, weekly or as necessary -should not be stored near a heat source -aprons should be hung up using hangers; should not be fold -gloves should be stored flat or upright on a custom holder
Checking for damage -to surface covering, seams and fasteners of aprons (if any) -check for flexibility, feeling for cracks
QC FOR X-RAY EQUIPMENT AND ACCESSORIES
LEAD RUBBER APRONS AND GLOVESTest to detect cracks on aprons and gloves Method -place the apron or gloves to be tested on the table top -use fluoroscopy system to examine the whole article *if radiography is to be used, placed cassettes under test articles and make separate exposures, ensuring that the whole article is examined
Evaluation -Look for cracks or other abnormal variations of density in the image