Main Article Content
Introduction: We are a high volume referral center for cast treatment of early onset scoliosis. Assessing the progress of treatment and effectiveness of each cast requires frequent use of radiographs which increases the risk of malignancy in young patients over their lifetime. We felt that frequently omitting radiographs may lead to wasted anesthetics and sought to find another method to reduce the dose of radiation these patients receive over the course of treatment.
Methods: Spinal radiographs are typically performed before and after casting while under anesthesia. Spine radiograph technique dictates a grid be placed between the patient and cassette to absorb any radiation that had been deflected by the body and not travelling directly perpendicular to the cassette. Without the grid, a significantly lower dose may be used. The image quality is non-diagnostic and grainy but endplates are still discernable. We eliminated the use of a grid in our practice and adjusted the dose accordingly to optimize endplate visualization. To ensure that measurement accuracy was not severely decreased, inter and intra-rater variability was measured before and after this change by several observers.
Results: Obtaining spinal radiographs without the grid resulted in an 80% reduction in total radiation dose received at the skin while having no effect on inter and intra-rater reliability of Cobb angle measurements. These radiographs allow for monitoring of treatment progress and cast quality with each anesthetic without omitting potentially important information.
Conclusions: Omitting potentially important radiographs may not be the only option for the reduction of radiation exposure in children undergoing Mehta casting. This non-conventional technique reduces radiation dose by 5 fold while still allowing accurate measurement of Cobb angles and therefore the progress of treatment and quality of casting. We are currently investigating a similar technique for longitudinal follow up pelvis radiographs in the treatment of hip dysplasia and cerebral palsy.