Tagged RBC Scan

General

• For active bleeding of mid to lower GI system

• Tc-99m-RBC

• Dose

  • Adult = 15-30 mCi

  • Children = 0.3 mCi/kg (minimum 2, max 20)

• Detection of 0.1 ml/min

• Images typically obtained for 60-90 min

• Image rate not to exceed 1 min (too slow)

• Bilateral photopenic areas with central hazy area of increased uptake = ascites with centrally located bowel

Technical Points

• Look at the first pictures and follow normal course, do not just skip to the end. If you skip to the end and there is a bleed you will definitely see blood but you will think the bleed is in the distal colon because that is what the last pictures are taken of. However you can have a bleed in the more proximal bowel which will be seen on the earlier studies and because of normal bowel peristalsis it will carry blood to the distal bowel and you will be fooled into thinking the bleed is more distal than it actually is.

• Need to be able to identify the vascular distribution and what portion of bowel the bleed is from

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