RadteraGI Bleeding Scan (Tc-99m Labeled RBC)
NM+ ContrastAbdomen & Pelvis
Indications
- Localization of active lower GI bleeding
- Intermittent / obscure GI hemorrhage
- Detection of bleeding too slow for angiography (>0.1-0.2 mL/min)
Patient prep
- No fasting required (study is often urgent)
- Patient should be actively bleeding for positive study
- IV access; obtain blood for in vitro/modified in vivo RBC labeling
Contrast
AgentTc-99m labeled autologous red blood cells (in vitro UltraTag preferred)
RouteIV
Dose20-25 mCi (740-925 MBq)
TimingDynamic imaging begins immediately; delayed/intermittent imaging up to 24 h for intermittent bleeds
Technique
- LEHR collimator, 140 keV, anterior abdomen/pelvis in FOV
- Flow phase 1-5 sec/frame for 60 sec, then dynamic 1-2 min/frame for 60-90 min
- Cine review to detect appearance and antegrade/retrograde movement of activity
- Delayed images if no early bleed; re-image when symptoms recur
Series / Sequences
| # | Series / Sequence | Plane | Notes |
|---|---|---|---|
| 1 | Flow phase | Anterior | Vascular/blood pool baseline |
| 2 | Dynamic blood pool | Anterior | 1-2 min/frame x 60-90 min; watch for focus that moves with bowel |
| 3 | Delayed images | Anterior | Up to 24 h for intermittent bleeding |
Key points
- Bleeding identified as a focus of activity appearing on serial images that conforms to and moves within bowel lumen
- Cine review is essential to localize and distinguish bowel from fixed blood-pool structures (vessels, kidneys, bladder)
- More sensitive than angiography for slow/intermittent bleeding
- Good RBC labeling efficiency critical; free pertechnetate causes gastric/GU/thyroid activity (false interpretation)
References
• SNMMI Procedure Guideline for Gastrointestinal Bleeding Scintigraphy
• Radiopaedia: GI bleeding scintigraphy link
• Radiopaedia: GI bleeding scintigraphy link
Source: Researched — verify against your institution
‹ PreviousGastric Emptying Study (Tc-99m Sulfur Colloid Solid Meal)Next ›Hepatobiliary Scan (HIDA, Tc-99m Mebrofenin +/- CCK/Morphine)
Reference template — verify and adapt to your scanner, vendor and institution before clinical use. Not a substitute for clinical judgment.