Suboptimal patient positioning with panoramic and CBCT imaging: effects on dose

Area of Science:

• Radiology
• Medical Imaging
• Radiation Dosimetry

Background:

• Patient positioning is crucial for diagnostic image quality and radiation safety in dental radiography.
• Understanding the impact of positioning variations on radiation dose is essential for optimizing exposure protocols.

Purpose of the Study:

• To evaluate the effect of suboptimal patient positioning on effective dose (E) and equivalent doses during panoramic and cone beam computed tomography (CBCT) examinations.
• To identify specific positioning errors that influence radiation exposure levels.

Main Methods:

• Simulated radiographic examinations were performed on a tissue-equivalent phantom using a RAYSCAN Alpha Plus 160 X-ray unit.
• Various suboptimal positioning scenarios were tested, including anterior/posterior shifts, chin tilt, rotation, and lateral shifts.
• Optically-stimulated luminescent dosimeters were used to measure effective dose (E) and equivalent doses to specific organs.

Main Results:

• Most suboptimal positioning variations did not significantly increase effective dose (E) for panoramic radiography, with rotation being an exception.
• Chin elevation during CBCT imaging led to significant reductions in E for both 10x10 cm and 16x10 cm fields of view.
• Chin elevation also notably decreased equivalent dose to the thyroid gland in CBCT procedures.

Conclusions:

• Suboptimal patient positioning does not generally increase radiation exposure in panoramic and CBCT radiography.
• Chin elevation is an effective strategy for reducing radiation dose, particularly to the thyroid gland, during CBCT imaging.