CAMRT Radiography Practice Exam

How does increasing the patient size typically affect the radiation dose in CT imaging?

1. Reduces the dose

2. Increases the dose

3. No effect on the dose

4. Varies depending on the scanner

The correct answer is: Increases the dose

Increasing the patient size generally results in an increase in the radiation dose during CT imaging. This is primarily due to the need for the imaging system to provide a sufficient amount of radiation to penetrate the larger body tissues effectively. In CT, the amount of radiation delivered is often adjusted based on the patient’s size to ensure adequate image quality. Larger patients require more radiation to achieve images with the necessary contrast and resolution, primarily because the x-rays must pass through a greater volume of tissue. This translates to a higher dose to ensure that the diagnostic information is satisfactorily captured. Additionally, many modern CT scanning protocols incorporate automatic dose modulation based on the patient's size. However, basic principles dictate that as size increases, the required dose does typically increase in order to maintain image quality. This understanding is crucial for radiologic technologists as they must weigh the need for high-quality imaging against the principles of radiation safety and dose optimization, keeping in mind the ALARA (As Low As Reasonably Achievable) principle when working with larger patients.