Radiation doses of indirect and direct digital cephalometric radiography

Aim The aim of this study was to measure organ doses and calculate the effective dose for indirect and direct digital cephalometric exposures. Material and methods Indirect digital cephalometric exposures were made of a Rando(R) phantom head using a Cranex Tome(R) multipurpose unit with storage phosphor plates from Agfa and the direct digital ( Charge Coupled Device, CCD) exposures were made with a Proline Ceph CM(R) unit. Exposure settings were 70 kV and 4 mAs for indirect digital exposures. Direct digital exposures were made with 70 kV, 10 mA and a total scanning time of 23 s. TLD700(R) dosemeters were used to measure organ doses, and the effective doses were calculated with ( effective dosesal) and without inclusion of the salivary glands. A pilot study was carried out to compare diagnostic image quality of both imaging modalities. Results Effective doses were 1.7 muSv for direct digital and 1.6 muSv for indirect digital cephalometric imaging. When salivary glands were included in the calculation, effective doses(sa)/ were 3.4 muSv and 2.2 muSv respectively. Organ doses were higher for direct digital imaging, except for the thyroid gland, where the organ doses were comparable. Diagnostic image quality of indirect and direct digital cephalometric images seemed comparable. Conclusion Effective dose and effective dosesal were higher for direct digital cephalometric exposure compared with indirect digital exposure. Organ doses were higher for direct digital cephalography. From preliminary data, it may be presumed that diagnostic image quality of indirect and direct digital cephalometric images are comparable.