Quality Control

QUALITY CONTROL(QC) AND QUALITY ASSUARANCE(QA) OF X-RAY MACHINE

TOOLS REQUIRED

Beam alignment test tool: This tool is used to test central beam alignment consists of a typically a plastic cylinder with a small metal ball(stainless-steel; lead) embedded at each end and placed on the center of collimator test tool.

When exposed and processed, it should produce an image where the top ball merges(overlap) perfectly with the bottom ball if the beam alignment is correct and vice versa indicated misalignment of the beam.

Quality Control

Allowing technicians to visually verify if the X-ray beam is centered and perpendicular to the image receptor by ensuring the ball images appear as one when properly aligned.

The deviation of the beam from the perpendicular is determined from the location of the image of the top ball in the circle of the radiograph.

Quality Control

Focal spot test tool: This tool consists of a hollow cylinder with an acrylic circular disc containing 12 groups of bar patterns, Each group consists of 6 lines-sub group.

Tool is placed on a non-screen cassette loaded with film.

Film is exposed and processed and bar pattern on a radiograph is observed -the smallest group of 6 bars clearly resolved indicates the focal spot size.

Note: Regular checks ensure the focal spot size remains within acceptable limits.

Tube Voltage Test

Kvp meter is the tool used to test tube voltage, Uses two solid state detectors with different beam hardening filters to measure peak tube voltage.

when exposed to radiation the ratio of signals produced by these detectors will be proportional to peak tube voltage.

• Corrections may be needed for beam filtration

Note: Consistent kVp settings are necessary for maintaining proper image quality.

Importance of Kvp meter

• The kVp meter ensures that the voltage applied to the X-ray tube is correct.
• The kVp meter helps to control the amount of radiation exposure to the patient.

The kVp meter helps to control the quality of the X-ray image.

Time checker

Spinning top test tool is the tool used to check the exposure time.

Consists of rotating brass plate with a rectangular hole which produces equally spaced density patterns on film when exposed for a set time.

• Tool is placed on cassette loaded with film.
• Equal density patterns are produced to check exposure time accuracy

Note: Regular timer checks help maintain optimal exposure times.

Tube Housing Leakage Test

Radiation survey meter is the tool used to Measures radiation leakage from the tube housing at different locations and distances.

Collimator of tube housing is fully closed and tube energized at maximum rated potential and current Acceptable tolerance limit is typically >115 mR/hour at 1m from focus.

Periodic tests are essential to ensure radiation safety.

Note:

• These tests help ensure proper functioning and safety of x-ray machines.

Acceptable tolerances and testing frequencies should be established.

Regular quality control tests are important for maintaining equipment performance and patient safety.