Medical Imaging Preventive Maintenance Tips for Siemens CT Systems

Posted April 25, 2019 by Jeremy Probst

Computed tomography (CT) is considered one of the most important medical developments of the last 50 years. Godfrey Hounsfield, the engineer who helped develop the technology, was awarded a Nobel Prize for his work in 1979. Today, CT systems are among the most valuable equipment inside any healthcare facility.

Medical imaging engineers are charged with making sure the CT scan stays up and running so patients get important diagnoses and receive the care they need. Of course, one of the best ways to avoid system downtime and needless service calls is to make sure to conduct regular preventive maintenance (PM) cycles on the equipment.

Below are some insights and advice for medical imaging professionals who are tasked with conducting PM procedures for Siemens CT systems.

When and Why Should CT System Preventive Maintenance Take Place?

Preventive maintenance on CT systems should take place twice per year. Many engineers, however, choose to split up the process, completing one set of steps first and then another six months later.

The entire PM cycle takes around six hours to complete and, for many Siemens CT systems, the OEM instructions include more than 200 pages full of things for imaging engineers to check off.

While the PM cycle may seem like tedious, uninteresting work, we do it for the same reasons we change the oil in our cars every 3,000 miles. We are trying to prevent problems with expensive equipment from occurring in the first place while ensuring it operates effectively and lasts for its expected usefulness.

Limiting system downtime is the name of the game in medical imaging. Conducting a thorough PM shows you’re the kind of proactive engineer who pays attention to the smallest details and understands that what you’re doing impacts both hospitals and the patients they serve when the moment of truth arrives.

Common PM Replacement Parts for CT Systems

Siemens PM documentation dictates that certain parts should be replaced every two years. That includes batteries, uninterrupted power supplies (UPS devices), and computer tower BIOS batteries. So, make sure you check and keep records accordingly.

Other parts that commonly need replacement before or after PM include fans, air filters, overvoltage protection in the power cabinet, and brushes.

If you know you need to order Siemens CT system replacement parts before you begin PM, you can get them from Technical Prospects and take advantage of one of the lowest DOA rates in the industry.

Cleaning the Siemens CT System

CT systems with carbon brushes can have a lot of dirty build-up in them. You’ll need a good pair of gloves, not only to keep you clean during PM, but also to protect your hands from sharp metal edges and to protect the CT’s brushes and slip ring from the oils on your skin.

Some of the newer systems, such as the Siemens Definition AS, have bristle brushes rather than carbon. Even though there won’t be as much visible black dirt to clean, imaging engineers should still clean the gantry, inspect brush blocks, and check the slip ring for damage.

CT equipment can produce excess conductive carbon material throughout the system, especially when regular PM cycles fail to take place. This can lead to data communication errors, which are notoriously tough to troubleshoot. So, keeping the system clean will prevent headaches in the long run.

You can use a small vacuum to clean out electronic assemblies and other areas of the system, but make sure it is an ESD safe vacuum with a HEPA filter. Do not use compressed air during cleaning because it is an electrostatic generator that could cause damage to components.

There are many different air filters and fan assemblies in Siemens CT systems. You’ll need to clean them all and make sure the fans are working. Siemens suggests checking fan operability by simply sticking a zip tie between hard-to-see fan blades so you know they’re spinning.

Use a lint-free towel and an alcohol-based cleaner to wipe down the unit’s detector window, which can also collect contrast and matter buildup over time, causing issues.

Overall, good cleaning during preventive maintenance ensures longevity of the system. To help you get the job done, Technical Prospects offers CT Preventive Maintenance Kits with all the supplies you’ll need. Watch the video below to learn more.

Inspecting the Siemens CT System

Perhaps the most important part of the PM cycle is when you inspect the CT system’s brushes and slip ring. Pull the blocks off and look for excessive wear on the data, high voltage, and low voltage brushes.

The OEM says there should be at least 8 mm of brush remaining from the tip of the brush to the arrow or maximum wear point. Anything less than that and replacement CT brushes should be ordered. Make sure each brush is put back in the same spot and orientation as when you removed it for inspection.

See the brush inspection process for yourself and get additional advice for this portion of the CT PM cycle in the video below.

When you inspect the slip ring, you’ll be physically feeling for ridges, grooves, and burs – any imperfection that indicates wear around the circumference. Imperfections on the slip ring will decrease the life of the CT system’s contact brushes because they damage the tips. It also creates more dust in the machine, which can negatively affect functionality.

When you find imperfections, use an abrasive cleaner pad to smooth out the surface of the slip ring. These pads, which are specifically made for slip rings, are provided with our CT Preventive Maintenance Kits. Get more advice on slip ring inspection and fixing imperfections in the video below.

Yet another factor to examine is the water cooler pressure, which you’ll need to do on systems such as the Siemens Sensation 64. If you get a low pressure reading, you should fill the gantry with water, which will allow excess air to escape and properly pressurize the system. See more about how to do this in the video below.

Lubricating the Siemens CT System

The lubrication of bearings and other moving components in a CT system is essential, but too much grease can be just as detrimental as using too little. Don’t overlook the functionality of the patient table. Check all movements of the patient handling system (PHS) to be sure everything operates smoothly.

Imaging engineers who want to be extremely accurate can use a kitchen scale to weigh and measure precise pumps of grease. An improper amount could cause the system to seize up, which is something you don’t want happening when a patient is being scanned.

You’ll get the grease you need and a gun for applying it when you order a CT Preventive Maintenance Kit from Technical Prospects.

Finishing Up Preventive Maintenance on a CT System

There are a few steps to complete as you wrap up PM on a Siemens CT scanner and turn the system back over to the site.

Run system backups: The end of preventive maintenance is a good time to set restore points and run backups for critical data, hardware, and software as well as any updates to the operating system and antivirus protection.

Quality control (QC) test: Follow OEM guidelines and use manufacturer-provided phantoms for conducting test scans and fine tuning before handing the system over. This is also an important safety step to ensure proper doses of radiation.

Field service report (FSR): A comprehensive report detailing what you did to the system shows you were following OEM guidelines and lets others know about things that should be addressed to keep the CT in working order, including identification of failing parts.

If you have questions or run into problems while going through the PM cycle for a Siemens CT system, Technical Prospects is here to help in the moment of truth. Our 24-hour technical support is always available to engineers working on Siemens medical imaging equipment.

You can also get preventive maintenance tips for other modalities on our website.

From commonly replaced medical imaging parts to hard-to-find parts for systems that have surpassed end of life (EOL). Technical Prospects is dedicated to being a reliable partner offering parts, training, and support to the imaging engineers working hard behind the scenes. Contact us for a parts quote or to find out more about our company.

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