The X-ray tube is the single most expensive consumable part of a CT. It comes as no surprise, considering an X-Ray tube plays a vital role in ensuring images are clear and precise.
Because of this, it makes sense to gear one’s preventative maintenance toward extending tube life.
Below we will discuss preventative maintenance tips that can help extend the life of your Toshiba Aquilion CT tube, ensuring optimal performance and cost-effectiveness.
life expectancy of Toshiba Aquilion CT Tube
Generally, your Aquilion tube should easily reach a 500,000 slice count. Counts nearing 1,000,000 slices are not unheard of on the high end.
So why would a tube fail much earlier than that? There are a number of reasons, but the most common, especially for systems with replacement tubes, is that the cooling system has been compromised.
Temperature Is Key
The Toshiba Aquilion family of CTs uses a Varex tube design that has some exceptional engineering characteristics. In terms of X-ray tube life, the main feature is the efficient removal of heat from the tube. In a maintained system, this characteristic gives long tube life.
CT tube cooling is dependent upon the heat exchanger. Essentially all the tube’s heat dissipation is done by a series of coils in the exchanger. The transfer and dissipation of heat across these coils is via a water/glycol cooling fluid, which flows through the tube and back through the heat exchanger.
What Causes High Temperatures in CT Tubes?
Air in the heat exchanger pump- this will lead to a slowing or outright stoppage of coolant flow. This also means there is air in the tube, which will limit normal heat transfer.
If the tube is generating an X-ray, heat energy is being produced and absorbed in the tube. When problems in the exchanger pump slow or stop cooling, the heat continues to build rapidly.
The parts affected first tend to be the rotating components, which then affect other portions of the tube in a chain reaction. This chain reaction often proves to be of extremely annoying and wallet-harming proportions.
Luckily, as a safeguard against this, Toshiba CXB tubes are equipped with a thermal sensor. When the thermal sensor is tripped, it’s an indication that the cooling system is failing. It's important to note, that the heat already “in transit” will cause a temporary rise in temperature afterward.
The weakest link in the Aquilion tube cooling loop may be the cooling line quick disconnects. These tend to leak when separated, allowing fluid out and air in.
Keeping Your CT Tube Cool
The best help for cooling system health is to purge/recharge (P/R) the cooling system at each tube change. A heat exchanger P/R is an effective way to remove excess air from the exchanger coils.
This is not normally done, partly due to cost, time, and lack of awareness, but is an added measure that can yield great results for proper cooling.
Two P/R options:
- Varex will purge/recharge the heat exchanger for a relatively nominal sum, but you’ll need to send the unit out to them. There is a purge kit available from Varex that can be used on-site by service engineers. This measure is helpful, but will not yield the same quality results as a full P/R.
- If a P/R isn’t enough and a replacement is necessary, Block Imaging offers the option to buy a purged/recharged heat exchanger in exchange. When replacing a tube or heat exchanger we recommend a P/R of the component you aren’t replacing. If the tube is being replaced, P/R the heat exchanger, and vice-versa. When purchasing either of these components, be sure to ask if the cooling fluid has been recharged.
The Takeaway
In the future, monitor your system for thermal warnings from the tube or the heat exchanger.
If the worst happens and your tube fails outright, there are providers you can turn to for affordable CXB tube replacements. Block Imaging is one of those providers, and is ready to help!
With over 35,000+ parts in stock, same-day NFO shipping Mon-Fri from 7AM-5PM, we've got you covered. Browse our in-stock parts, and contact our parts team today.
Steve Rentz: April 18, 2024
