Artifacts Caused by Collimator Grease (RT)

1 Process Overview

Image Artifacts have been generated and reported on some CT systems due to the contamination of the bowtie and the primary copper filter. This contamination is from the lubricating grease used on the filter positioning drive screw assembly.

The following information may apply in general to all 46-296300G5, 2214768, 2214768-2 and 2214768-3 Collimators.

The inspection takes less than 5 minutes. It consists of simply examining the Copper primary filter.

2 Required Tool

Bright Flashlight

3 Procedure

1. Remove Mylar Scan Window

2. Launch Diagnostic Data Collection, DDC, from the Service Desktop.

   1. Select DIAGNOSTICS.

   2. Select DIAGNOSTIC DATA COLLECTION.

   3. Select POSITION TUBE.

   4. Enter 180 and execute.

   5. Select STATIC X-RAY OFF.

      1. Filter AIR.

      2. Slice Collimation Largest Aperture, 4 x 5.00 for example.

   6. Select ACCEPT RX.

3. Using a flashlight, inspect the primary copper filter by looking down into the collimator output port. See Figure 1.

   note:

   The copper filter should be clean, dent and scratch free. Discoloration is acceptable.

   If contamination is visible Figure 2, proceed to Collimator Cleaning Procedure (RT)

Figure 1. Collimator Output Port

Figure 2. Extremely Contaminated Copper Filter