![]() Most ring and band artifacts will require troubleshooting from a qualified field service engineer. Contact us for a list of recommended service providers. Contact MRI Repair Service Engineer (FE)Ĭall qualified Field Service Engineer for CT repair service. Restoring power to system resets all gantry subsystems and provides subsystem LED self tests. This will remove all power from system and provide enough time for any stored voltage to bleed off. Perform gantry reset by pushing the button with the blinking LED on the left or right gantry interface panels. Power back on using the green start button. ![]() Last Resort: Power down entire system from A1 main disconnect power that is supplying power to CT system from facility alternatively shut down gantry with gantry enable button on PDU. Issues with power supplies or faulty fans can prevent heat from being evacuated from CT Gantry. High gantry exhaust temperature relative to ambient temperature can be an indication that gantry cooling subsystem is not functioning properly.Īre fans not working? Check for radiant heat from gantry fan ports. Heat buildup inside of the CT Gantry can cause damage to sensitive electrical components and power supplies. Check the top of your CT gantry to make sure all fans are on. Pause scanning until CT scan room temperature has normalized and is within recommended scanning temperature. Rising temperatures in scan room can overheat internal components and cause CT artifacts. Scanning should not be performed above 83 degrees F. Ideal scan room temperature ranges from 68 degrees to 73 degrees Fahrenheit. 4 items to check before making a service call CT Scan Room Temperatureįirst, check your scan room temperature. Most causes of white ring artifact and dark ring artifact will likely be within the CT Gantry and will require a Field Engineer. Also try to choose different collimator setting by reducing detector coverage in an attempt to exclude bad channel during scan data acquisition.Ģ) If you cannot scan with a configuration that is free of ring artifacts or excludes bad data channel, you most likely have a Data Acquisition subsystem issue. If experiencing ring artifacts during scanning try:ġ) Choosing a different detector configuration ex. Ring artifacts occur as a result of data acquisition or detector issues. CT Scanner Ring Artifactĭescription: Clearly defined edges and usually localized to channel segmentation no more than 1mm in thickness. Perform daily calibrations again after identifying and clearing beam obstruction. Water mean value only passes specification if value is within -3 to +3. Additionally, CT daily QA scans may show elevated mean values. Avoid spilling any solution into CT gantry.įInally, after contrast has been cleaned, perform daily calibration and test scans using quality assurance phantom.īeam obstructions during daily calibrations cause image artifact. In this case, pour a small amount of solution on cloth and wipe with cloth to avoid excessive liquid. ![]() Then, use warm water and rubbing alcohol solution on a clean cloth to wipe off any visible contrast along beam path. Do not apply liquid solution if holes are visible in mylar window. ![]() How to remove contrast from CT mylar windowįirst, inspect mylar window for any small holes in the ring. Contrast present on mylar window around the CT bore or beam obstruction during daily calibration can be cause for artifact. Induced CT Artifactĭescription: Typically represented as band artifacts or ring artifact with blurred edges. Artifact descriptors will help in isolating cause of CT artifacts. Perform test scans using water phantom and examine the nature of the artifact.
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