Linear Accelerator Operators

What Operators Do

Operators are the primary persons involved in the actual administration of radiation therapy. The treating doctor (usually called a Radiation Oncologist) is responsible for prescribing and planning the treatment and for weekly checkups on the health of the patient. The Linear Accelerator Operator is responsible primarily for seeing that the prescribed treatment is carried out appropriately when the patient shows up for a treatment.

Operators are thus, usually responsible for treatment done with one (or a small set of) machines. The schedule is maintained by others, and this places the operator in the position of a "production assistant" making sure that all those persons scheduled for treatment on a particular day get treated. In addition, they have a responsibility to the patient to operate the machine safely and to treat the patient kindly and with respect. This mix of goals is not unusual in medical practice.

The Therac-25 operator greets the patient on arrival, escorts them into the treatment room and sets up the patient on the treatment table using the field light to target the beam. This may involve marking the patient’s skin for the pattern of radiation that is required. The operator then enters treatment parameters into the machine directly in the treatment room. He or she then leaves the room and uses the computer console to confirm the treatment parameters (electron or X-ray mode, intensity, duration, etc.). The computer then makes the appropriate adjustments in the machine (moving the turntable, setting the scanning magnets, setting beam intensity etc.). This takes several seconds to do. If the operator notices an error in the input parameters, he or she can, during the setup, edit the parameters at the console without having to start all over again from inside the treatment room.

When the computer indicates that the setup has been done correctly, the operator presses the actuation switch. The computer turns the beam on and the treatment begins. When treatment is over, the operator checks with the patient, updates records on that patient and then admits the next patient into the treatment room.

One of the advantages of the significant computerization of the Therac-25 machine was that setup for treatment could be done much more quickly. This allowed the operator more time to speak with the patient and interact with them about their health concerns. In addition, this increased efficiency allowed more patients to be scheduled during a day. Thus, more patients could be treated, but the atmosphere was not reduced to that of a factory.

Dealing with difficulties

If a treatment resulted in a suspend or cancellation by the machine, the operator had several choices. For some machine errors, the operator could simply press the "retry" button and attempt the therapy over again. If only half the prescribed dose had been introduced (e.g. the beam was a lower intensity or cut off early) the rest of the dose might be applied in a second, immediate, treatment.

If the error was more significant, many hospitals and facilities would have a medical physicist on call. The physicist could be called in to look at the machine immediately. For facilities without a full time physicist, contract service was usually provided. This required scheduling (but usually within the same day as the problem).

All errors (whether by the machine or by the operator) were supposed to be logged and reported. Medical Linear Accelerators do age over time, and older machines often produce more errors. Five to ten years is a reasonable life span for a machine. Close tracking of these errors by operators allows the hospital or facility to know when to replace a machine that is generating more errors than is acceptable. Even if errors are not harmful to patients, when a treatment must be restarted several times, it may reduce patient confidence in the facility.

Pressures for Production

Production pressures are always present when an expensive medical technology is being used. Machines need to treat enough patients to pay for themselves over their lifetime. And in for-profit medical facilities the additional pressure of generating a profit is added to this production pressure. Another kind of production pressure is generated because of concern for the patient. Patient schedule requires treatments on certain days and it disrupts the patients’ lives and slows down their treatment to have to reschedule them for another day while the machine is being checked out.

These production pressures generate the desire to "push patients through." If a machine gives only a portion of the prescribed dose, an operator will often repeat the treatment with enough radiation to add up to the total prescribed dose. Sometime this repeat has been done up to twelve times to produce the appropriate treatment with a balky machine. At times, operators have been known to collaborate with medical physicists to use jumper cables to override a particular safety mechanism, if their judgment is that the override will not reduce safety.

Operators who feel that pressures for production have decreased safety can certainly report this to their supervisors (usually a supervising operator with additional training and experience). They also have been known to leave facilities because of concern over safety.

Training and Licensing

There is currently no industry-wide standard certification and education for medical linear accelerator operators. There are about 102 radiation schools in the country, ranging from certificate programs (about 12 months in length) to four-year bachelor's degrees. Licensing standards differ from state to state. In some states, operators are required to be licensed by the American Registry of Radiologic Technologists (ARRT). This licensing requires a certified educational program and regular updating of skills for re-registration of the license.

Other states, however, have designed their own tests to set minimal standards for operators, and some of these tests are much less involved that that required by ARRT. In addition, many of these states do not require continuing education of operators. There are no national standards for training or licensing.

Operators who are licensed have more professional standing to resist production pressures that they feel lead to unsafe treatment of patients. In addition, their training gives them better arguments to stand up to hospital administrations that attempt to put pressure on technicians to push large numbers of patients through treatment in spite of possible dangers.