RNI common imaging techniques Flashcards

1
Q

2 methods used for renal RNI

A

renal cortical imaging

dynamic renal imaging

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2
Q

renal cortical imaging

A

99mTc dimercaptosuccinic acid (DMSA)

  • adult dose is 80M
  • dose is scaled down for paeds - minimum of 15 MBq
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3
Q

dynamic renal scanning

A
99mTc mercaptoacetyltriglycine (MAG3) is mainly used - 100MBq
99mTc diethylenediamine penta-acetic acid (DTPA) also commonly used - 300MBq
  • scale down dose for children - minimum dose of 15MBq
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4
Q

indications of static DMSA scan

A
  • recurrent UTI
  • horseshoe kidney
  • ectopic kidney - grown in the wrong place
  • assessment of reflux
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5
Q

renal cortex DMSA adult prep

A

80MBq is injected 2 hours prior to the scan- to allow effective uptake

at 2-3 hrs it gives the best binding for imaging

  • patient must avoid pregnant women and public transport after injection for next 24 hrs
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6
Q

renal cortex DSMA scan paediatric prep

A
  • booked onto children’s ward
  • cannulated on ward and dose is administered
  • injection is given 2 hrs prior to scan, to allow effective uptake
  • 2-3 hours - best binding for imaging
  • patient returns back to ward
  • radioactive nappies are stored
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7
Q

renal cortex DMSA technique (adults)

A
  • patient sits erect in between the gamma camera heads on rni imaging chair
  • Posterior view
  • LPO
  • RPO
  • 300 second images
  • patient should avoid movement
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8
Q

renal cortex DSMA scan - paeds

A
  • patient lies on the scanning table with the gamma camera above and below patient
  • sponge pad is provided for support and reduce movement
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9
Q

renal cortex DSMA scan - paeds views

A
  • posterior view
  • LPO
  • RPO
  • 300 second images
  • patient must avoid movement - can cause blurring
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10
Q

renal cortex DSMA scan - after care adults

A
  • keep hydrated and flush twice after urination

- they can go home as normal, however avoid women and public transport

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11
Q

renal cortex DSMA scan - after care paeds

A
  • paed nappies need storing for 1 week and then disposed off in 14 days in normal waste bin
  • keep eating and drinking normally
  • if sedation is used, paed must be admitted to children’s ward and monitored - radiation sheet attached to their notes
  • cannula is removed and placed in sharp bin if no longer needed
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12
Q

Advantages of DSMA imaging

A
  • relatively low dose
  • demonstrates physiology rather than anatomy
  • assesses differential uptake/function of renal cortex
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13
Q

disadvantages of DSMA imaging

A
  • does not show anatomy
  • invasive and paeds may require sedation
  • more costly if child is admitted onto the ward
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14
Q

Dynamic renogram

A

assesses renal function and excretion

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15
Q

Dynamic renogram indications

A
  • evaluation of obstruction
  • assessment of differential renal functions
  • assessment of perfusion
  • renal trauma assessment
  • diagnosis of renal artery stenosis
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16
Q

Dynamic renogram patient prep

A
  • patient well hydrated prior to scan
  • document all medications that can affect study e.g. blood pressure medication
  • ## they must empty bladder before scan
17
Q

Dynamic renogram patient positioning

A
  • either supine or erect with gamma camera posterior - so that kidneys are closest to the camera
  • make sure patient is cannulated and is patent (flushed with saline)
18
Q

Dynamic renogram technique

A
  • inject patient
  • imaging starts immediately
  • 1-3 seconds per frame for 60 seconds - assess renal perfusion
  • measure syringe post injection to calculate absolute dose
19
Q

advantages of MAG3 imaging

A
  • relatively low dose
  • demonstrates physiology - assesses differential function
  • can distinguish between calculi and physiological obstruction
  • doesn’t require contrast
  • can also assess reflux
20
Q

Disadvantages of MAG3 imaging

A
  • doesnt show anatomy
  • invasive - may require sedation in paeds - can alterresults
  • may need rebooking, if child is non-compliant
21
Q

RNI Imaging of the endocrine

A
  • can assess parathyroids, thyroid and adrenal glands
22
Q

reasons to scan thyroid glands

A
  • assess thyroid function - usually after abnormal blood test
  • assess treatment post ablation dose
23
Q

if thyroid carcinoma is suspected, which radionuclide is preferred

A

iodine 131

24
Q

Thyroid RNI - patient prep

A
  • patients should not have CM in previous week to scan
  • they must discontinue their thyroid interfering medication
  • nil by mouth 4 hrs before scan
  • patient should wear loose clothing
  • empty bladder before scn