When it comes to removing and installing linear accelerators, speed is of utmost importance. A linear accelerator replacement is a huge logistical undertaking that can cause a lot of stress for both doctors and patients in radiation oncology centers. The physical process, from start to finish, can take as long as six weeks. While this may not have a huge impact on a hospital or larger facility that has multiple machines, for a smaller, free-standing clinic that is replacing its only machine, the effect it has on revenue and treatment schedules can be very severe. Doctors have to refer their patients out until the new machine is ready, which can potentially lead to loss of revenue for the facility and potentially harmful inconvenience for the patient.
When buying a used or refurbished linear accelerator, how important are the HV hours, also known as “beam hours?”
Beam hours for linear accelerator are like the mileage on a car. They reflect the amount of time that beam has been on, and therefore are a good indication of the “wear and tear” on a particular machine.
Generally speaking, machines with higher beam hours will sell for less than those with lower beam hours, all other things being equal. Of course, there are dozens of other variables that influence the price of a linear accelerator, like the age, technologies and upgrades.
Linear accelerators have two different components that allow for images of the patient to be made while the patient is on the linear accelerator:
1. MV Imaging Devices. These devices, also referred to as EPIDs (Electronic Portal Imaging Devices), produce an image of the patient by the use of the mega voltage (MV) beam of radiation that the linear accelerator emits to treat the tumor(s).
2. KV Imaging Devices. These devices produce clearer, x-ray images of the patient through the use of an x-ray tube that is mounted onto the linear accelerator.
Is your facility considering selling or replacing diagnostic imaging or radiation therapy equipment? There are several options to choose from. We have highlighted the “pros” and “cons” of each.
In 2013, a survey was conducted among medical physicists and published on the Global Medical Physics list server. The survey asked physicists which higher photon energy is preferred, primarily between 10MV, 12MV, 15MV and 18MV.
All linear accelerators manufactured today include the 6MV photon energy, which is the most widely used energy for performing IMRT. However, higher photon energy options exist, and the selection can often be confusing.
Who better to ask than the medical physics community? The results, we found, were surprising. Given the choice to alter the energy pairs on their linear accelerators, physicists chose 10MV as the preferred second energy.