Which of the following is cited as the largest contribution to unnecessary patient radiation dose?

• A. failure to communicate
• B. failure to collimate
• C. excessive kvp
• D. excessive mas

Answer: (B)

Limiting the X‑ray beam to the area of interest through proper collimation dramatically reduces the amount of tissue irradiated. When the field isn’t well collimated, a larger area is exposed, and more scatter is produced inside the patient. That scatter adds to the patient’s dose and can reach tissues outside the diagnostic area. Compared with adjusting kvp or mA, which change dose within the same field, expanding the field size affects the total volume exposed and the resulting scatter far more, making it the biggest, most preventable contributor to unnecessary dose. Communication is important for safety and exam success, but it doesn’t directly change the dose delivered.