Linear accelerator maintenance cost analysis

Abstract

Purpose: Medical linear accelerators are the most costly standard equipment used in radiation oncology, however the service costs for these machines are not well understood. With an increasing demand for linear accelerators due to a global increase in cancer incidence, it is important to understand the expected maintenance costs of a larger global installed base so that these costs can be incorporated into budgeting. The purpose of this investigation is to analyze the costs for medical linear accelerator service and maintenance at our institution, in order to estimate the service cost ratio.

Methods: We collected the costs of parts used for all service work done on 32 medical linear accelerators over a two year period. The data was segregated by center, machine, linear accelerator type, and failure area in the machine.

Results: We found the service cost ratio (excluding software support expenses) to be 3.13% [2.74%, 3.52%,]. We observed a variability of parts costs, and overall variability of the service cost ratio to be between 2.14% and 5.25%. This result is lower than other estimates for service costs for medical equipment in general and medical linear accelerators specifically. Two-thirds of the service costs were due to labor costs, which indicate the importance of a well-trained service technician workforce.

Conclusions: We estimated the service cost ratio for medical linear accelerators to be 3.13% [3.52%, 2.74%] of the initial capital cost. This result was lower than other estimates of the service cost ratio.

Keywords: linear accelerator; linear accelerator components; linear accelerator maintenance cost analysis; maintenance costs; service cost ratio.

FIGURE 1

Adaptation of Figure 1A from reference (van der Giessen). The Y‐axis are costs in ECU, or European Council Units, which was the precursor to the Euro. The exchange rate was about 1.25 USD per UCU.

FIGURE 2

Total parts costs for each center, averaged over a 1 year period. Costs are in Canadian dollars.

FIGURE 3

Parts costs for each center, separated into categories for machine type or spare parts, averaged over a 1 year period. Costs are in Canadian dollars. Centre 6 had 2 TrueBeam accelerators and 3 Clinac accelerators. These two TrueBeam accelerators had large parts costs, higher than the average of the 5 units at that center shown in Figure 2.

FIGURE 4

The total parts costs for each linear accelerator included in the study, separating Clinac units from TrueBeam units. The linear accelerator in the study were assigned a study number, which is plotted on the x‐axis. Costs are in Canadian dollars.

FIGURE 5

Parts costs, expressed as a percentage of the total parts costs, plotted from largest to smallest on a cumulative plot. From this plot we can see that 80% of the parts costs were attributed to 14 of the 33 linear accelerators.

FIGURE 6

Parts costs, plotted against the median age of the linear accelerator at the time of the study. On the x‐axis, the median age is newest to oldest going from left to right. The older linear accelerators were Clinac style machines, while the newer machine (purchased from about 2009 onward) were TrueBeam style accelerators.

FIGURE 7

Plots of component cost for all machine types (top), Clinac only machine types (middle) and TrueBeam only machine types (bottom). A demarcation is added to mark the component areas that contribute 80% of the machine costs. The areas that are present in the top 80% of the costs for all three plots are kV, MV, Thyratron, ion chamber, MLC and PCB (printed circuit board).

FIGURE 7

Plots of component cost for all machine types (top), Clinac only machine types (middle) and TrueBeam only machine types (bottom). A demarcation is added to mark the component areas that contribute 80% of the machine costs. The areas that are present in the top 80% of the costs for all three plots are kV, MV, Thyratron, ion chamber, MLC and PCB (printed circuit board).