Career Episode 3
Title of Position
After I was trained in cardiac catheterization imaging system, I had undergone advanced training in vascular and cardiac image quality customization. This training was offered for experienced Engineers who would support the field engineers in image quality issues. After this training, our organization had given additional responsibility to support the entire south zone on technical issues and image quality problems. I had received image quality problem in one of our Biplane vascular catheterization imaging system. This imaging system had been dedicated for interventional neurological procedure such cerebral aneurysm, embolization and brain coiling. P.E.3.1
I visited the site and found that the system had an issue on radiation dose also. The customer had complained about frequent hair loss among the patients treated for the cerebral aneurysm. It was a challenge for me since this system had two set of image receptors (one was named frontal and the other as lateral)so I had to check both the planes and rectify the fault. I had visited the site to observe the work flow and the operational issue in the catheterization lab area. I observed many issues in the work flow and the radiation techniques applied during the procedures. The protocols used in the radiation techniques needed to be optimized for low dose and good image quality. Also I found that the radiographers had to be trained fully on various operating procedures of the system. P.E.3.2
Personal Workplace Activity
Before the calibration and troubleshooting, I conducted various checks on the system I found the issues in the following area
• The radiation dose protocols not optimized
• Radiation Dose limits are high
• Efficiency of the image intensifier (image receptor) low
• Poor Image resolution
• Low image contrast image
• Video chain issues
First I had optimized the techniques used in protocols. I had set the radiation parameters such as KV, MA, Pulse Width, and dose level to produce good image quality with less dose. Also I insisted the customer to implement correct operational procedures to reduce the patient skin dose to minimum level. I had suggested the following safety procedure during the radiation. P.E.3.4
• Keep the distance between patient to image intensifier minimal
• Maintain the source to image distance maximum
• Use the spectral filter to reduce the soft radiation which can cause image quality issue and excessive harmful soft radiation.
• Decrease the frame rate of the acquired cine image sequence. This will reduce the radiation dose significantly
• Optimized the fluoroscopic acquisition parameter to reduce the entrance dose.
• Advised the technicians and doctors to use the Hard Collimation to improve the image quality and reduce skin dose.
• Use small magnification mode
First I measured the fluoroscopic and cine entrance dose at the image intensifier input with the ion chamber dosimeter and found the dose level on the frontal plane image intensifier entrance dose level increased considerably. But at the same time the lateral plane image intensifier had showed normal entrance dose levels. So I suspected the problem in the frontal plane image intensifier. The efficiency of the image intensifier to convert the x ray photon to light had reduced considerably over the period of usage. P.E.3.5
The conversion factor is the recommended method to evaluate the efficiency of the image intensifier Tube. The conversion factor is defined as the output luminance level of an image intensifier divided by its entrance exposure rate....
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