Nuclear Genitourinary Exam

Measurement of relative renal function

Evaluation of a renal transplant

Evaluation of acute renal failure

Assess for renal artery stenosis

Assess split renal function for native kidneys

Assess for UPJ obstruction

bolus of 10-20 mCi Tc99m DTPA or Tc99m-MAG3

preferred over Tc99m-DTPA

primarily excreted via tubular excretion

high first-pass extraction

able to see perfusion and function even in a failing kidney that would not be as easily seen in DTPA

functional radiopharmaceuticals

tubular agents

clearance by 89% by active tubular secretion

recommend to use of patients with decreased renal function and infants

90% of the dose is excreted into the urine by glomerular filtration within 2 hours

used to assess renal blood flow, function,
and drainage of the pelvicalyceal systems ureters

most commonly used to measure GFR

no need to be NPO
light meal and adequate hydration
urinary catheters should be put in for patients who cannot void

Technologist should start an IV on patient

Patient Position

supine

Use dose to mark sternal notch in top one third
of image and bladder in bottom one third of image.
Use dose to ensure that patient's left and right sides are in FOV

Post void can be acquired in supine position for 2 minutes

Instrumentation

single or dual head gamma camera

LEAP

Matrix: 128x128
Energy: 140 keV
Window: 20%

Flow: dynamic acquisition
30 frames x2 s/frame
Function: dynamic acquisition 19 minutes of
20s/frame, compressed to 1min/frame
Total: 22 minutes

Data processing

ROI's drawn around both kidneys, abdominal
aorta, and background

Time-activity curves are generated that tell physician
the half-time.

Normal study

The activity of radiopharmaceuticals should arrive
in each renal area at the same time and with equal
intensity.

Activity will be seen in the renal collecting system,
ureters, and bladder.

Abnormal study

Areas of relative decreased activity resulting from cysts
or avascular tumors may also be seen in the flow sequence.

Evaluation and detection of vesicoureteral reflux

Commonly perform in children

Ask patient to void before catheterization

establish an indwelling Foley catheter

1 mCi of Tc99m-sulfur colloid or DTPA

ROA: into the Foley catheter
by injection port

Camera type: LFOV gamma camera
Camera position: Posterior

Data acquisition

Energy: 140 keV

Window: 20%

Collimator: LEHR
Matrix: 128x128

Patient position:
Supine

Additional views: full bladder
RAO/left anterior
oblique postinfusion
postvoid

Time/view:
dynamic: 10-15 s/frame
static: 120 seconds

Total bladder volume of residual postvoid volume
and bladder volume at initiation of reflux can be measured.

Normal study:
Increasing activity in the bladder without
reflux into the ureters

Abnormal study:
show ureteral reflux, especially during urination
Reflux bladder volume and the volume of reflux into the kidney can also be calculated

Detection of pyelonephritis

Differentiation of renal mass from normal variant
Confirmation of suspected column of Bertin

Identification of functioning renal tissue in patients
with congenital abnormalities

Evaluation of renal cortex

detection of the presence of absence of small renal infarctions

Well hydrated

Void prior to imaging

Subtopic

5 mCi of Tc99m-DMSA

15-20 mCi of Tc99m-GH

Pediatric patient: 50 uCi/kg

Camera type: LFOV gamma camera
Energy: 140 keV
Window: 20%
Collimators: LEHR
Matrix: 128x128

Patient position: supine
camera position: posterior

Injection to imaging time:
immediate and 2-4 hours after injection
24 hour delay is optional

Time/view:
Dynamic: 2-4s / frame for 60-120 seconds
Static: 500k to 1 M counts
SPECT: 2-4 hours post injection. 25-30 s/projections

Normal study:
show smooth renal contour
Both kidneys should have equal amount of
radioactivity and uniform tracer distribution

Abnormal study:
congenital abnormalities: horseshoe kidney,
ectopic kidney, and the absence of kidney.

Evaluation of renal obstructive nephropathy

Evaluation of hydronephrosis

Distinguish between obstructive hydronephrosis
and nonobstructive collecting system dilation

Pregnant/ breast-feeding:
pregnant must be excluded for this exam
breast-feeding patient use the appropriate
radiation safety

Furosemide is contraindicated in anuric/
or dehydrated patients

Patient does not to need to be NPO
Light meal and adequate hydration
Technologists need to start an IV

Technologist need to start an IV on patient

Patient should be well hydrated
drink 10 to 16 oz of water over 30 min

Best with 10 mCi of Tc99m-MAG3

5 mCi Tc99m-DTPA may also be used

MOL: MAG3 is tubular secretion/
DTPA is glomerular filtration

ROA: IV bolus

Furosemide:
20-40 mg for adults
0.5-1 mg/kg for pediatrics
injected slowly over 1-2 min
image is continued for 20 min

Supine

Use dose to mark sternal notch in top one third of image and bladder in bottom one third of image. Use dose to ensure that patient's left and right sides are in the FOV.

Detector system

camera: LFOV Gamma Camera

Collimator: LEHR

Data acquisition

Dynamic/flow

Energy: 140 keV
Window: 20%
Matrix: 128x128

If a urodynamically significant outflow obstruction is present,
the affected kidney is unable to increase its urine flow rate
in response to the furosemide injection.

Have high sensitivity for the detection of urodynamically
significant ureteral narrowings.

Differentiate of renal vascular hypertension (RVH)
from renal artery stenosis

Diagnosis or exclusion of RVH

Pregnant must be excluded for this exam

Breast-feeding should be provided with
appropriate radiation safety

any recent nuclear medicine study

Only liquids for 4 hr before procedures
well hydrated

Diuretics should be discontinued for 3 days

ACE inhibitors and angiotensin II
receptor blocking agents should be
discontinued for 4-7 days

Obtain patient baseline of BP

Captopril
50 mg pill, PO 1 hr before procedure

Enalaprilat:
40 ug/kg IV over 3-5 min
wait 15 min then inject Rph

5-10 mCi of Tc99m-MAG3 via IV

Detector system

LFOV gamma camera

Energy: 140 keV
Window: 20%
Matrix: 128x128

Views: posterior

Flow study:
2 sec/ frame for 1 min
then stats every 30 sec for 20 min

Subtopic

Subtopic

Subtopic

Processing

Draw region of interest around each
kidney and the aorta

Draw 2 bg regions of interest
(one for each kidney)

Generate time-activity renogram curves

If abnormal, will need a follow-up study without
Captopril for comparison