Urology>>>>>Paediatric Urology Question 1#
Which of the following investigations has the lowest radiation dose?
A. Magnetic resonance urography (MRU)
B. Plain abdominal X-ray
C. MAG3 renogram
D. DMSA renogram
E. CT KUB
Correct Answer is BComment:
The approximate radiation burden for these investigations:
- MRU involves no radiation. However, the need to lie still during the investigation limits the test without general anaesthesia to those who infants less than 3 months old (‘feed and wrap’) and children above about 11 years.
- MAG3: 0.20–0.38 mSv (mSv = milli Sievert)
- DMSA: This is approximately 1 mSv/examination regardless of the age of the child (providing that the dose is adapted according to body surface). The radioactive tracer is taken up and binds to the proximal convoluted tubules and retained there with the image taken after 2–3 hours.
- Plain abdominal x-ray dose in a child 1.0 mSv.
- CT KUB: abdomen/pelvis child 10 mSv. Low-dose CT can achieve doses of less than 3.5 mSv, and ultra-low-dose CT of less than 1.9 mSv.