The intricacies of the linear accelerator, itself, combined with those of the patient positioning couch, the laser system and the treatment procedure’s computerized system, easily qualifies the linac as one of the most Byzantine pieces of medical equipment to ever cross a biomed’s path. Can you handle it in-house or must you opt for the service contract?

An experienced BMET would be hard-pressed to identify a piece of medical equipment more complex than a linear accelerator (linac). Or one where preventive maintenance and service procedures assume such a critical role with a tolerance for error set close to nil. Since many institutions have seen a rise in the number of radiation therapy patients, a demanding schedule of treating a different patient every 15 minutes throughout the day and evening is not unusual. More than half of all cancer patients receive radiation therapy.

Tim Waldron, M.S., a medical physicist at M.D. Anderson Cancer Center (Houston), explains that today’s high-energy linacs involve high-vacuum systems, large-scale water temperature controls, sophisticated electronics and motor action required for the precise motion of rather massive components, as well as extremely high voltages in a radiation environment.

These days, IMRT (intensity modulated radiation therapy) involves closely conforming the radiation beam to the tumor target while sparing normal tissue through the use of a multileaf collimator (MLC) with as many as 120 moving leaves that shape the beam in specific ways. Treatment planning, accomplished on a simulator, uses computed tomography (CT) digital images to direct the specifics of a treatment field.

Couple the intricacies of the linac itself with those of the patient couch used for positioning, the laser system that ensures proper alignment of the treatment area and the computerized system that encompasses the entire treatment procedure, and it becomes clear just how complicated this system is to maintain and service. It could be an untrained service technician’s worst nightmare.

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