We want to change from grid to air gap-technique, to hopefully reduce dose and maintain, or even increase, image quality.
The Lateral hip air gap technique has been described by Tim Barrall, Senior I Radiographer, the Royal Brampton Hospital, London in Imaging & Therapy Practice, January 1, 2004. The full text of this article is said to be available on highbeam.com with a subscription
In the past couple of years, we have experimented on using the air gap technique for lateral horizontal beam hips with our digital equipment (our particular equipment is known to require lower doses than CR in formost general bucky work). Because the patients we perform these on are immobile and on trolleys or beds, there is naturally an air-gap anyway. All we did was remove the grid, and refine our exposure and technique. We still try and position the patient as close to the edge of the bed/trolley on the side that the wall bucky will be on.
In our experience, it works well with mid and small sized patients. Overalll, we found with good collimation, lower exposures are required and I personally feel it provides appreciable if not better image quality. It can work with larger patients, but the collimation has to be tight enough for it to be successful. Depending on the gap between patient and bucky, we frequently leave the grid in for these patients.
However, I cannot formally comment on patient dose but given everything else we do remains the same yet a lower exposure is required without the grid, I can only surmise there is lower patient dose.
Hope this helps.
There are two good articles on the subject:
Barrall, T. (2004). Lateral hip air gap technique. Synergy, 20–23.
Flintham, K. (2006). Horizontal beam lateral view of the hip. Synergy, 15–17.
Due to their age good PDF copies aren't available,but I found them on Proquest database.
The Flintham article is available on mine or Kevin's researchgate publications
We have recently had a student complete a Masters dissertation on optimising HBL hip radiography when using DR. We can forward you some of the results/conclusions if this would be helpful. Sorry for the late reply.
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