How to measure the deterioration of a tube for a CT scanner (Updated 2021)

The humanity didn’t found perpetual motion machine yet. That is why every technology has limited resource. Some products are in commission for years (e.g laptop) and can complete different tasks very fast, if you use them according to instructions. But, some products can be used for clearly defined times. Hence, you are obliged to enumerate each usage and change such products at the right time.

CT scanner tube is one of such things that can be used limited number of times. X-ray tubes are expensive enough, so everyone tries to get as much as possible from them. However, it is a must to know when you have to use new X-ray tube.

That is why you are obliged to know how to adjust deterioration of a tube for a CT scanner.

Total patient exams

This method may be the easiest for measuring the run-out of ct tube. It shows how many times they were used to make an exam. You have to consider that this is the less compelling way to control the deterioration of ct x ray tube.

As you know, CT exams are carried out with different power level. Moreover, the deterioration mostly depends on time of using, not on the amount. Therefore, total patient exams is a very rough analysis for tube. You can use it only if you have no more data. 


The second indicator of deterioration is the total sum of extracts during one exam. This might give more accurate estimate for tube. Many producers point out to the acceptable number of clicks/counts for each ct scan tube.

Nevertheless, in some situations it is not enough to measure the run-out. The CT-scanner will not show you the volume of energy needed for each extract.

This method needs additional calculations. Thus, it is not comfortable. If you make wrong computation, you will found out that the tube is unsuitable or vice versa, you will change it earlier than it will be necessary.

Scan seconds

The most familiar way to measure the deterioration of a tube for a CT scanner is to cipher the scan time. With this approach you will be able to found out how long the tube was powered. Such computations are more detailed, then the previous. However, they are not the best.

In this situation, you are unable to calculate the energy that passed through the tube. That is why you have to consider the particular qualities of an exam to find out an approximate volume.

Milliampere seconds

This is the best method to calculate the lifespan of the tube. It gives necessary clues related to the continuance of each exposure, the amount of energy that passed through the tube and others. If you have a possibility to analyze mAs of, just do it. You will get the most correct data and will be able to found out “the moment of death” of the tube. The real usefulness of mAs is to determine the average mA a site has been running their tube at, that is to say- how "hard" they typically use it.

Final thoughts

Despite the effectiveness of various methods, it is a must to use all of them. It is very difficult to measure the deterioration of a tube, because its term of service is almost unpredictable. The more numbers you will have, the more scientific the verdict will be.