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Thallium-201 Study


  • You have been referred for a Thallium Study in which imaging is 

  • A Thallium Scan is effective in evaluating myocardial perfusion (looking at blood supply to the heart muscle).

  • Thallium can also be used to visualise certain tumours such as Glioma, Myeloma, Glioblastoma, Osteosarcoma and Lymphoma.

  • PET imaging is now considered the modality of choice when attempting to differentiate these tumours.

  • The test involves a small injection of Thallium-201 into a vein in the arm (like having a blood test).

  • There are rarely any side effects with this injection.

  • If we are assessing your hearts blood supply, then you will undergo a Cardiac Stress Test (see Cardiac Sestamibi Study for details). Your heart will be imaged whilst in a Stressed state and 3 hours later at a Rest state.

  • All images are done whilst lying on a bed and a Gamma Camera (1) rotates around your chest (SPECT/CT) (2). This takes 20 minutes.

  • For imaging of tumour sites, you receive a small injection of Thallium-201, wait 20 minutes, then have Total Body Images using a Gamma Camera (1).

  • You are then asked to return after 2 hours for a repeat Total Body Image. This takes 20 minutes.

  • Often, we require to image your body in 3D (SPECT/CT imaging) 'after' the total body image.

  • With SPECT/CT imaging, the same Gamma Camera simply rotates around your body, taking images all the time. This can take 15-30 minutes.

  • You receive a slight radiation dose by having a Thallium Scan with SPECT/CT ~ up to 8.75 times your yearly background radiation (3).


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.

  • If you are having the Thallium Scan for imaging tumours, then there is no preparation i.e. eat and drink as normal. If you are on any medications, please take these as normal.

  • If you are having the Thallium Scan for your heart, then there is some preparation. It is similar to that of the Cardiac Sestamibi preparation. Please click here to be re-directed to those instructions....

  • 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 32-hours. During this time, you need to express and discard your breast milk as often as required. 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) SPECT/CT imaging (Single Photon Emission Computer Tomography / Computer Tomography). CT does emit radiation

(3) We all receive a yearly background radiation dose ~ 2.4mSv. Thallium Scan with SPECT/CT ~ 21mSv =  8.75 times yearly background dose.

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