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CSF Clearance Study


  • You have been referred for a CSF (Cerebrospinal Fluid) Clearance Study in which the rate of CSF clearance is observed over a period of time.

  • The test involves a small injection of  radioactive “tracer” into a Rickham's Reservoir (small tubing allowing CSF access into the ventricles of the brain).

  • The tracer we use is called 99mTc-DTPA (99m-Technetium diethylene-triamine-penta-acetic acid). There are rarely any side effects with this injection.

  • During the injection of tracer, we obtain a sample of CSF for analysis.

  • Initial images are done of the head/neck (with a standard), chest and abdomen using a Gamma Camera (1). This takes 20 minutes.

  • Once the initial images are complete, you will be asked to return in 3-hours for more images.

  • Ratios are obtained between the ventricles and the standard. These in turn are comparatively analysed  to assess the extent of clearance.

  • 6-hour and 24-hour images are also necessary "if" there has been delayed clearance from the ventricles.

  • You receive a slight radiation dose by having a CSF Clearance Study ~ up to 0.08 times your yearly background radiation (2).


Patient Preparation:

  • If you are pregnant, trying to fall pregnant or breast feeding, you must inform our staff.

  • If you have had prior imaging e.g. PET, Nuclear Scan, CT, MRI, X-Ray, Ultrasound, etc... please bring these with you.

  • Please also bring your referral and any blood results that you may have had done.

  • There is no preparation for a CSF Clearance Study i.e. eat and drink as normal.

  • If you are on any medications, please take these as normal.

  • Wear comfortable clothing and minimise the amount of metal jewellery you have on (all metal objects will need to be removed prior to imaging).

  • Important Note: You cannot have this test if you have had a PET or Nuclear Scan within 24 hours prior to this test. If you have had Iodine-131 therapy, allow 4-weeks before having this test. Please ring to discuss booking options.​


Breast-Feeding Mothers: Once you have been given the tracer, you need to stop breast-feeding for two feeds. During this time, you need to express and discard your breast milk. You will need to bottle-feed your child during this period.


(1) A Gamma Camera is a device that detects gamma-rays (gamma-rays are very similar to x-rays) and does not emit any radiation.

(2) We all receive a yearly background radiation dose ~ 2.4mSv. CSF Shunt Patency Study ~ 0.18mSv = 0.08 times yearly background dose.

value. quality care. convenience.

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