When purchasing a CT scanner, the seller will likely give you the machine’s usage data in one of three formats. The usage of the machine is important to disclose so that the buyer can anticipate the maintenance costs and lifespan of their purchased equipment. When selling CT imaging equipment, it’s important to be able to know this data in order to pass that information on to the buyer for the same reasons, and in order to determine a fair selling price.
Some parts of CT scanners require periodic replacement, even with normal, responsible machine operation, based on the amount of usage. The x-ray tube is the most common part to require regular replacement, and its usage is typically measured in total patient exams, milliampere seconds (mAs), or scan seconds. Understanding these metrics and what they mean helps determine the investment value of the equipment as a whole.
What are Milliampere Seconds?
Milliampere seconds (mAs) are a very common metric in measuring x-ray tube usage. They represent an all-encompassing data metric, measuring the total amount of time power has been applied to a CT scan machine. This includes during scans, machine calibration, and testing. This metric is often used more specifically to determine the amount of power or “how hard” a scan tube has been used, by dividing the number of mAs by the total number of scan seconds.
Scan seconds measure more specific machine usage: how long a machine was powered and scanning a patient. This means that scan seconds do not account for the calibration time of the machine, unlike mAs, and are often used in describing the lifespan of an x-ray tube. X-ray tube lifespans are listed in millions of scan seconds, typically somewhere between 500,000 and 700,000 scan seconds. This usually translates to 2-3 years of usage, although the number of scan seconds/longevity of an x-ray tube varies widely, based on the model and the way the tube is used. Properly maintained ct scan equipment generally yields a greater life expectancy.
Patient Scan Metrics
The total number of patient scans is the metric least likely to be used in buying or selling CT scan equipment because it doesn’t describe the usage of the equipment in a very detailed way. Different scans are completed for different amounts of time and at different levels of intensity. Sometimes replacement equipment will offer a very broad range of potential patient scan numbers, but they’re meant to be considered in a general context, and not as definitive data.
Overall, combining these metrics is the most effective way to understand the lifespan potential of your CT scan machine or replacement parts. Looking at specifics as well as the overall view of the data should give you a good idea of what your equipment is capable of, and when to expect regular maintenance and repairs to occur.