Topic 5- Nuclear medicine diagnostics of the urinary tract. Dynamic renal scintigraphy with diuretic, radiopharmaceuticals, phases, renogram curves, clinical applications. Captopril renal scintigraphy. Cortical renal scintigraphy – clinical applications. Nuclear medicine diagnosis of testicles. Application of SPECT/CT.
Nuclear medicine evaluates the function of the kidneys rather than only their anatomy.
Types of Renal Scintigraphy
There are two main renal scans.
1. Dynamic Renal Scintigraphy
Evaluates:
- Renal perfusion
- Renal function
- Drainage
- Urinary obstruction
2. Cortical Renal Scintigraphy
Evaluates:
- Renal cortex
- Cortical scars
- Pyelonephritis
- Differential cortical function
Dynamic Renal Scintigraphy
Dynamic renal scintigraphy is a functional nuclear medicine study in which sequential images of the kidneys are obtained immediately after intravenous injection of a radiopharmaceutical.
It evaluates:
- Blood flow
- Tracer uptake
- Urine drainage
Principle
Radiopharmaceutical is injected intravenously.
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Travels through bloodstream.
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Kidneys receive blood.
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Tracer is filtered or secreted.
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Collected in collecting system.
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Excreted into ureter.
Gamma camera continuously records this process.
Radiopharmaceuticals
The syllabus does not specify individual tracers, but in routine nuclear medicine the commonly used tracers are:
Tc-99m DTPA- half life- 70 mins
- Filtered by glomeruli
- Measures GFR
Tc-99m MAG3
- Secreted by renal tubules via active tubular secr
- Better when renal function is impaired. With normaI renal function 70% of the administered activity of the radiopharmaceutical (RP) is excreted within 30 minutes after the application.
Procedure
Patient: usually in supine
- Well hydrated
- Asked to empty bladder
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IV injection
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Gamma camera starts imaging immediately
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Images obtained continuously for about 20–30 minutes
Phases of Dynamic Renal Scan
Phase 1 — Perfusion Phase
Immediately after injection.
Assesses: Renal blood flow.
Normal: Both kidneys enhance simultaneously.
Phase 2 — Functional Phase
Tracer enters renal cortex.
Measures: Renal uptake.
Reflects renal function.
Phase 3 — Excretory Phase
Tracer moves:
Kidney
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Pelvis
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Ureter
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Bladder
Assesses drainage.