When our imaging department,
Community Hospital of the Monterey Peninsula (CHOMP), transitioned
from film to digital radiography in 2002, we slowly discovered that
the training we received was not adequate. Although we learned
the basics of how to take and post process exposures, we weren't
taught how we could save a significant amount of dose to the patient
or how to properly critique the images. It wasn’t until early
2006, when I heard Barry Burns give numerous talks at the Atlanta
Society Conference, that I learned that digital radiography can
inherently use higher kV with lower mAs.
Working together with colleagues and two of our radiologists, we set out to test the limits of image processing and to re-educate ourselves in the art and function of diagnostic medical imaging. We wrote a proposal and got approval from our hospital administration for the purchase of a head and neck, upper extremity and thorax phantoms to go along with our abdomen phantom. We also purchased a DUKE phantom and a digital dosimeter to conduct experiments with different processing parameters. Our goal was to lower the patient absorbed dose by increasing the kV by 15% and cutting the mAs in half, while keeping digital noise to a minimum and image quality in the diagnostic range per our radiologist' preferences. We succeeded beyond our expectations and discovered that we were actually able to half the mAs again, thereby cutting the dose to the patient by 66%!
During this time, I also did numerous experiments concerning Exposure Index (EI) numbers and what it takes to corrupt them. It became readily apparent that if the centering and collimation are good, the EI numbers are very reliable. I also studied how much over-exposure can occur and still have a presentable and passable image which has led to the “Dose Creep” crisis that is plaguing the entire U.S.
I’ve been an active radiographer for over 35 years and employed as a Clinical Instructor/Staff Radiographer at CHOMP in Monterey, California since 1990. I’ve also been associated with the Cabrillo College Radiology Program as Clinical Instructor since 1991. Since 2006 I have traveled extensively throughout the U.S. and Canada lecturing on how best to put into practices:
As a shooting tech, I fully understand the problems radiographers encounter and through my seminars and consultations I’m able to help solve these problems. The goal of my easy to understand talks is not to teach you how the equipment works, but how to work the equipment safely and effectively.