Journal

This week I have been on placement in the Western General hospital. This was my first time in this particular hospital so I was naturally a bit apprehensive, not knowing where to go, or knowing any of the staff. However these fears were soon
allayed and, in the end, I really enjoyed it. The staff were lovely, so friendly and helpful and it wasn’t long before I relaxed into my placement. This allowed me to concentrate on familiarising myself with the equipment and finding out how the department runs.

I was curious to see that they performed chest x-rays with the upright bucky. Previously I had only seen a chest x-ray performed with the cassette placed outside the bucky without the use of a grid. I wondered why they chose to perform the examination this way and also how they could be sure they were going to get the entire chest on the image.

After observing this technique a few times, I began to understand the difference between placing the cassette inside or outside of the bucky. The radiographer showed me how the cassette is centred to the bucky, so this gave the radiographer a reference with which to firstly position the patient and then collimate the beam. Once I performed a chest x-ray using this technique I found it quite straight forward.

After performing the examination, I noticed the exposure set on the console seemed very high. When using the bucky for the examination, there is then a need to increase the KVp, which I thought would increase patient dose. I couldn’t understand how this technique could conform to the ‘low as reasonably practicable’ rule regarding radiation, as set out by IRMER 2000 (Ionising Radiation (Medical Exposure) Regulations). However it was explained that this was the radiologists request as this would allow him to see behind the mediastinum and heart for any pathology.

I have since looked at two chest x-rays, one of which I performed using the high KVp and in the bucky, and one taken out of the bucky using the lower KVp from a previous hospital. On comparison, in my opinion, it was possible to see much more detail in the image using the higher KVp and the grid. There is better detail in the lungs and behind the heart as well as through the spine. I found this an interesting method and at some point would like to investigate this method further. I have done some research and since found out the technique used at the hospital can be used to reduce exposure error. An
iontomat is used in collaboration with a high KVp and a grid, while using the smallest possible mAs, therefore reducing patient dose. I have included a link for a website I found while researching the different exposures and techniques,
which gives examples of images at different exposures.

This entry was posted on Friday, February 13th, 2009 at 3:40 pm and is filed under Reflectives. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.