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Radiographic Technique Still Matters For Image Quality and Patient Dose
Posted on Saturday, March 23rd, 2013, under Radiography
Shirley Bartley, M.B.A., RT (R)(N)
The new technologist at the hospital radiology department went to do a portable in the ICU. The patient looked average size. She looked for the technique chart to set the correct exposure factors. There was no chart to be found. She guessed at the technique based on what she could remember from the last place she worked. When the new tech returned to the department the supervisor was reviewing the image. “You are going to have to repeat this portable chest. There is an image quality problem. You didn’t penetrate the mediastinum.” The supervisor told the new tech.
If the kVp is too low the anatomy will not be properly penetrated. The fine detail in dense areas of the body will just not be there. This will jeopardize the radiologist ability to make a correct interpretation of the patient’s condition.
A few minutes later the new tech was working in room 2 with a seasoned employee. The new tech selected the radiographic technique from the anatomic programing feature on the operator’s consol. “Don’t use that. It doesn’t work. I have my own technique.” The new technologist made a mental note to try to remember the technique.
Without standard technique systems that are used by everyone image quality will be inconsistent. It is difficult for the radiologist to see changes in the patient’s condition when totally different radiographic technique is used. Technologist that just “remember” their own techniques are frequently wrong.
After lunch the new tech was working with a radiology student. They did an abdomen using automatic exposure control (AEC). Viewing the image, the new tech pointed out that the exposure indicator value was well above the acceptable range. The students said, “They don’t pay any attention to the number here.”
With digital systems the image that is over exposed no longer comes out black. The only way we can determine that the patient was over exposed is with the exposure indicator value. The AEC unit that is not properly calibrated will not produce the correct quantity of radiation for the image. When the exposure indicator value is ignored the patients may be overexposed unnecessarily.
These three situations describe common problems for image quality and patient dose. ISS, Inc. can assist you in maximizing image quality while keeping patient dose as low as reasonably achievable (ALARA). For more information access our recent white paper.