Arguably the most important objectives of an imaging engineer’s job are about safety; making sure the equipment is safe for use, and ensuring our personal safety on the job. Virtually all of us face threats to our health on the job every day and some of those risks can be life threatening. The types of risks and their severity varies depending on the modality of the scanner. As we gain experience and confidence it is human nature to get a little lax, and sometimes we even make jokes about safety. When I was in school, I remember a sign in the laser lab that said, “Do not look into laser with good eye.” Unfortunately, I have experienced some wake-up calls about the importance of safety during my career. The worst was at Technicare in the mid-1980s, when a rookie CT engineer was killed during a PM because he didn’t properly bleed off the voltage in the transformer tank.
In the USA and most countries, your employer is responsible for providing information, tools and equipment regarding your personal safety on the job. The manufacturers of the equipment (OEMs) also have a responsibility, to publish user and service documents that warn of potential risks and dangers, and explain how to mitigate them. Ultimately though, we are each responsible for our own safety.
The risks to personal safety vary, of course, with the type of scanner on which you are working. MRI scanners may have the most personal safety factors. There is the magnetic field, which can accelerate metal objects toward the gantry with deadly speed and force. The RF amplifiers have such high voltages that you don’t even need to touch the anode of the RF tube, it will come out and get you! There is also risk of a helium quench when working on MRI systems, and of a magnet explosion when filling the cryogenic chamber of the magnet.
CT scanners and X-ray systems have dangerous high voltages in the generators and tubes as the major risk. There are mechanical risks, as well, especially with the spinning gantries of CT. Ionizing radiation does not cause immediate effects and once was thought to be safe even for fetuses. Now, we wear those detectors because we know the cumulative effect can cause cancer.
Nuclear medicine has some shock hazards and some scanners have serious mechanical risks. There are also risks from the radioactive isotopes that are used. And if you are working on PET scanners, you have the combined risks of CT and nuclear scanners.
Ultrasound systems probably have the least risk to personal safety of any scanners, but there are still ways you can get hurt. Some ultrasound units have user interfaces that raise and lower and other pinching risks. The electrical shock risks in ultrasound systems are relatively low (especially now that CRTs have almost disappeared). There are some dangerous voltages found in the switching and transmitter power supplies, which are called “high voltage” in ultrasound systems. These high voltages are typically from 200 to 400 VDC with ripple. I sometimes make light of the term high voltage when it is used in ultrasound; X-ray and MRI systems have thousands of times more energy. However, in school we were taught those voltages can be the most lethal, so they really shouldn’t be taken lightly.
There are some on-the-job risks that are universal to imaging engineers. All AC mains voltages can be dangerous and we should always follow the Lock-Out, Tag-Out (LOTO) procedure appropriate for the scanner. Other omnipresent risks are the dangerous microbes, both bloodborne and otherwise, that have become a part of our world. Wearing personal protective equipment (PPE), properly disinfecting equipment prior to servicing (and sometimes during), and the simple but important act of washing and sanitizing your hands should become routine.
And perhaps the most dangerous part of many jobs is driving from one site to another, while all the time people are calling or sending you text messages. Let’s all pledge to not succumb to the distractions of our smartphones and endanger ourselves and the lives of others.
At this time of year we often give thanks for our lives, and wish others good health in the coming year. It is a good time to resolve to not become complacent, to heed warnings in service manuals, glove up and scrub, use LOTO techniques, discharge those anodes and check your work. To quote a line from an old TV show: “Let’s be careful out there!” ICE
Jim Carr is Director of Service and International Operations for AUE. He may be contacted via email at JCarr@auetulsa.com.