How often is it safe to have a CT scan for kidney stones?

Can kidney stones be picked up on a CT scan ?

• Which is more accurate CT scan or ultrasound, or both in conjunction with each other.

• Answer:

  A non-contrast abdomen and pelvis CT scan is the most commonly used imaging test for kidney stones. "Ultrasound This test uses high-frequency sound waves to produce pictures of internal structures (e.g., organs, kidney stones). Ultrasound can detect a dilated (stretched) upper urinary tract and kidney caused by a stone lodged in the ureter, but usually cannot detect small stones, especially those located outside the kidney. It is the preferred imaging method for kidney stone patients who are pregnant." AND: "Computerized tomography (CT Scan) This test uses a scanner and a computer to create images of the urinary system. It is performed quickly but may have difficulty detecting small stones located near the bladder. CT scan can also help identify medical conditions (e.g., ruptured appendix, bowel obstruction) that cause symptoms similar to kidney stones. Newer scanners do not require a contrast agent. The non-contrast CT scan is the most common imaging test used to evaluate a possible kidney stone attack. If any stones are found, a plain abdominal x-ray is also taken to determine their size, shape, and orientation. X-rays are used for follow-up studies to monitor the stones' progress." http://www.urologychannel.com/kidneystones/diagnosis.shtml So CT has advantages (finding other pathology, better at seeing stones outside of the kidney, like in the uterer etc) and risks (radiation).