Why are rectangular collimators preferred over circular ones?

Rectangular collimators are preferred over circular ones primarily because they effectively reduce the amount of unnecessary radiation exposure to surrounding tissues. By limiting the x-ray beam to the area of interest—such as the dental structures being imaged—rectangular collimators minimize the exposure of adjacent tissues, which is crucial for patient safety and adherence to the principle of ALARA (As Low As Reasonably Achievable). This targeted approach not only protects the patient's health but also potentially reduces the overall radiation dose received during dental imaging procedures, enhancing the safety profile of radiographic examinations. The design of rectangular collimators aligns with optimizing radiation use while ensuring that the necessary diagnostic information is still captured.