Purpose: To reduce the radiation exposure of plain radiographs of the entire spine depending on specific indications, since these are frequently performed examinations of children and young adults with scoliosis and to determine objective quality control criteria to ensure accurate assessment.
Materials and methods: In this prospective randomized study 323 patients underwent plain-radiography of the entire spine with standard and 50 % reduced dose. In an experimental pilot-study this target-dose was determined using an Alderson-Phantom. The evaluation of the experimental radiographs, as well as, the randomized plain-radiographs was conducted using the following criteria: endplates (Cobb-angle), spinal process and pedicel (rotation), lateral margin of the vertebral body (lateral alignment), identification of C7 / S1 (perpendicular). Two radiologists evaluated these criteria using a score ranging from 1 (definitely assessable) to 4 (not assessable). If one single criteria was evaluated with a score of 3 or more points or more than 2 criteria with 2 points, the radiograph was scored as "not assessable". The statistical analysis was conducted as a non-inferiority-trial.
Results: Seven (2.4 %) of the 290 examined x-rays were scored as not assessable. There was no statistic inferiority between the examinations with standard or reduced dose, while singular assessment of the defined criteria was likewise dose-independent.
Conclusion: Plain-radiography of the total spine in patients with scoliosis can be performed with a dose reduction of 50% without a loss of validity. The obtained quality control criteria were clinically applicable.
© Georg Thieme Verlag KG Stuttgart · New York.