Organ doses and subjective image quality of indirect digital panoramic radiography

Objectives To determine if slight variations in exposure will affect diagno stic image quality and absorbed radiation doses for digital and analogue pa noramic radiography. Methods: Thermoluminescent dosemeters were placed in the thyroid gland, eye s, submandibular glands, parotid glands and skin of two human cadaver heads . Three different exposure settings were used: 70 kV, 120 mAs; 77 kV, 75 mA s; and 81 kV, 60 mAs. Subjective image quality was assessed using a phantom head. Storage phosphor (SP) images were printed on film and both analogue and SP images were assessed for their subjective image quality on a five-po int rating scale. The results were statistically analysed using logistic re gression analysis and chi (2) tests. Results: Highest organ doses were measured for the submandibular glands, fo llowed by the parotid glands. Salivary gland doses tended to be higher at l ower kV settings. Image quality was not statistically different for the dif ferent exposure settings. Imaging technique did not seem to influence diagn ostic image quality, except for the periapical status of upper premolars wh ere SP was better. The main reason for any differences appeared to be inter observer variation. Conclusions: Analogue and SP panoramic radiography performed equally well f or subjective diagnostic image quality. No significant differences could be found at the exposure settings used in this study. Radiation doses were hi ghest for the salivary glands, especially at lower kV settings.