Technical Issues Regarding Quality Assurance

11.    How do I set up a Quality Assurance program?
12.    Who performs what tests in a Quality Assurance program?
13.    How much time does it take to perform the Quality Control tests?
14.    How can I find a qualified Medical Physicist who is certified?
15.    How do I  check cassettes?
16.    How often do I need to replace screens and cassettes?
17.    What do I do if the processor is not used daily?
18.    How do I do the Sensitometry/Densitometry tests?
19.    Why do I need to do the Sensitometry/Densitometry Test daily? Why not weekly?
20.    I have equipment over 20 years old. Do I have to replace the equipment?
21.    Why do I need a yearly physicist QC survey?
22.    How do I find out what my average entrance skin exposure (ESE) is?
23.    Why is it important for me to know the entrance skin exposure (ESE)?
24.    Why are technique charts necessary?
25.    Do I need technique charts available for all exams or only the exams done in my office?


11.    How do I set up a Quality Assurance program?

There are several ways to set up a quality assurance program. For larger more complex facilities it may be appropriate to hire a qualified medical physicist to set up the quality assurance program for the office.  Please note:  now that the new rule is adopted, only those qualified medical physicists who are certified by the Department, may perform the annual quality control (qc) survey.   For a list of qualified medical physicists who are certified, click here for download.

For smaller facilities (and larger facilities if they choose) the Department has developed Compliance Guidance Documents on how to set up and carry out a quality assurance program. These guidance documents  include lists of equipment that may be needed, step-by-step suggested guidance, sample forms, manuals, procedures, and test methodologies. Please note:  the Compliance Guidance Documents are not regulatory standards.  They are developed as tools to assist the regulated community develop and implement their Quality Assurance Program. The Department has developed workshops to coincide with the implementation schedule as stated in the quality assurance new rules.

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12.    Who performs what tests in a Quality Assurance program?

The doctor, chiropractor, technologist, or other appropriately trained person may perform all of the daily, weekly, and monthly radiographic quality control tests. A certified medical physicist must perform the annual medical physicist's qc survey for radiographic, fluoroscopic or CT scan equipment.

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13.    How much time does it take to perform the Quality Control tests?

Many of the tests are simple observations. For example, are the view box light bulbs working or are the films and processor chemicals being stored properly? Other tests involve a little more time such as performing sensitometry and densitometry on a daily basis. These tests take an average of 3 to 5 minutes. If a quality assurance program is well designed and organized, the quality control tests should not be burdensome.

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14.    How can I find a qualified Medical Physicist who is certified?

For a list of qualified medical physicists who are certified, click here for download.

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15.    How do I  check cassettes?

You check cassettes by doing a visual check looking for dents and warping. Check to see that the cassette locks are functioning. You look at films to see if there are light leaks. Light leaks from the cassette will appear as dark areas in the same spot on most films. You look at the screens for artifacts and you do a screen/film contact test.   For the details of these procedures, click here to download the Radiographic Compliance Guidance Document.

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16.    How often do I need to replace screens and cassettes?

They should be replaced when they are no longer functioning properly and do not meet the QC tests listed above.

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17.    What do I do if the processor is not used daily?

Processor QC tests must be performed on every day radiographs are taken. If no radiographs are taken, even if the office is open, QC tests do not have to be performed.

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18.    How do I do the Sensitometry/Densitometry tests?

PROCESSOR SENSITOMETRY/DENSITOMETRY

The quality control procedure that monitors the processor is a key procedure and has been written with much detail.  For a complete and detailed procedure on sensitometry/densitometry and film processor quality control as delineated in the Radiographic Compliance Guidance Document, click here to download.

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19.    Why do I need to do the Sensitometry/Densitometry Test daily? Why not weekly?

Sensitometry/Densitometry must be done every day that x-rays are performed. Processing is known to be the weak link in the production of radiographs. It is the area of quality control that requires the most attention. The photographic film is very sensitive to processing changes. A processor that is out of control can negate the quality control efforts in other areas.

A study performed by Suleiman et al of the U.S. Food and Drug Administration (FDA) on 479 film-chemistry-processor systems in New Jersey documents these problems. The range of the relative speed of the processor using the same film ranged from 35 to 210 (100 is the norm). Over 50% of the facilities produced speeds from 35 to 100. The consequence of under processing is higher radiation exposure and film contrast degradation.

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20.    I have equipment over 20 years old. Do I have to replace the equipment?

No, you do not need to replace the x-ray equipment as long as it meets the current regulations and standards, produces quality radiographs and maintains low radiation exposure to patients.

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21.    Why do I need a yearly physicist QC survey?

The settings on the x-ray equipment tend to drift or go out of calibration over time. This survey is a means of ensuring that your equipment is operating properly and that your patients are receiving the best radiographs at the lowest radiation dose and entrance skin exposure possible. An annual medical physicist QC survey is required in the new QA rules.

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22.    How do I find out what my average entrance skin exposure (ESE) is?

A qualified medical physicist can determine the entrance skin exposure. This involves complex calculations and should be done only by an appropriately qualified individual.  

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23.    Why is it important for me to know the entrance skin exposure (ESE)?

You need to know the entrance skin exposure (ESE) to be assured you are taking films that are consistent with the average ESE for that type of exam. The National Evaluation of X-ray Trends (NEXT) study shows trends for various radiographic examinations nation wide. The NEXT studies have been performed by the Conference of Radiation Control Program Directors (CRCPD) in conjunction with the Food and Drug Administration for many years and have produced studies that document downward trends in the amount of radiation exposure to patients by examination type.  the NEXT data for chest, abdomen, and spine are in the radiographic Compliance Guidance Document.

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24.    Why are technique charts necessary?

By using technique charts properly, you can standardize the technique so the films will be consistent even if several technologists or doctors are taking x-rays on the same machine.

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25.    Do I need technique charts available for all exams or only the exams done in my office?

You need to develop technique charts only for the exams done in your office.

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