The Average Lifespan of Elekta Linear Accelerator Parts
In recent years, manufacturers of linear accelerators have been making their equipment service/maintenance business a major profit center. As a percentage of company sales, service contract revenues have grown year after year for the major linear accelerator manufacturers. While this makes investors in these companies very happy, the impact on the owners of the equipment is quite different.
As the costs of OEM maintenance contracts have increased, many hospitals and clinics are now exploring other options to maintain and repair of their linear accelerators. This article is to assist those centers seeking to do their own maintenance, hence lowering their costs of ownership. The big unknown is the cost of the parts. Having a sense of which parts may fail over time, can help the service engineers with better planning.
In the chart below, we have provided the average lifespan of various parts, based on feedback provided by facilities with differing levels of patient loads.
|Part||High use system
|Moderate use system
|Low use system
|Magnetron||2 yrs||5–6 yrs||5-6 yrs|
|X-ray tube||18 months||3 yrs||4+ yrs|
|XVI detector||5 yrs||7 yrs||10+ yrs|
|iView detector||2 yrs||4 yrs||4 yrs|
|Electron gun||1 yr||N/A||N/A|
|Thyratron tube||3 yrs||5 yrs||5+ yrs|
|Ion chamber||3–4 yrs||3–4 yrs||N/A|
|Reflectors||2–3 yrs||2–3 yrs||N/A|
|MLC camera||2–3 yrs (old type); much longer now||2–3 yrs (old type); much longer now||N/A|
The magnetron has significantly different expectations for lifespan depending on the model year of your Elekta linear accelerator. Many newer machines do not use a feedback system (generally those operating at or below 18 MV, like the Elekta Compact) and thus may need the magnetron replaced within 3-4 years. Older machines and those operating above 18 MV typically have a feedback system with a magnetron that can last up to 10 years.
The electron gun on a high-use linear accelerator can be replaced after a year, but can last over six years on a very low-use linac.
The thyatron tube, which delivers the pulses to the electron gun, has a consistent lifespan regardless of usage; feedback indicates a baseline expectation of three years, with five years as a reasonable upper bound.
Elekta linear accelerators’ ion chamber is a part that can be especially affected by local climate. High humidity can shorten its lifespan by two-thirds, with an average ion chamber needing replaced within four years and one in a high humidity location possibly as soon as one year from first use.
We’ve talked previously about the costs of replacing X-ray tubes in CT Simulators, but some of the same points apply here. Patient load widely affects the lifespan of the X-ray tube: at lower usage levels, your tube may last several years before needing replaced (one facility has used the same tube for over six years), but a higher daily patient load drops the number significantly.
Newer models in the Elekta linear accelerator line include the Versa and the Infinity/Axesse. Particularly with the VersaHD (in production since 2013), some of the upper bounds on part lifespan are yet to be determined. However, looking at some of the lifespan figures on earlier models can help frame expectations. High usage rates will always affect parts like the X-ray tube and the electron gun, but the MLC camera has a consistent lifespan.
Hopefully we were able to provide some insight when trying to determine the most appropriate service agreement for your Elekta linear accelerator. As usual, many factors can affect the lifespan of the parts, including but not limited to climate and humidity levels, patient load, and dose rates. For more information on Elekta linacs, parts, service agreements, or anything else related to radiation oncology, please contact info@OncologySystems.com.