This page gives advice for those wanting to refer patients for nuclear medicine investigations at University College London Hospitals NHS Foundation Trust. Given at the end of this page are appropriate referral guidelines for the tests we perform.

All medically qualified doctors with GMC registration can make a referral for a nuclear medicine test. If you are a junior doctor, the consultant in charge of the patient should be identified as being the referrer. GPs can also make referrals for certain nuclear medicine investigations.

Non-medical referrals can be made by Nuclear Medicine approved registered healthcare professionals from within UCLH. Non-medical referrals from outside UCLH are not possible currently. If you want to become a non-medical referrer, please email

For all referrals, please ensure that the patient is informed that they will be sent for a test before sending in the referral request. For many tests, a dose will be ordered in advance for each patient. Where patients cancel at short notice, we are unable to use the dose for another patient. All efforts will be made to process requests as soon as possible upon receipt.


Internal referrals within UCLH

All referrals should be made through EPIC. Please use the generic NM provisional codes when making your request. The Nuclear Medicine consultant will ensure that the correct test is arranged for you.


External referrals from outside UCLH

If you are working in a hospital and are wanting to refer a patient, please use this proforma. For GPs, please use this form instead.



Please inform us at the earliest opportunity if you wish to cancel the nuclear medicine investigation. Wherever possible this should be done via telephone to confirm that the message has been received, and that the patient does not continue to have the test. Furthermore, all our investigations require pre-ordered radiopharmaceuticals which will be wasted if we are not informed about a cancellation.



In alignment with UCLH policy, patients will be allowed two non-attendances before the request is cancelled. If you intend to re-refer the patient after non-attendance, please inform them how it important it is for them to attend their appointment.

Under the IR(ME)R 2017 regulations, certain information should be provided by the referrer. The table below taken from RCR guidance gives details of Essential, Expected and Desirable Information to be given with the referral.

Essential information

Accurate, up-to-date patient identification information

Requested Exam
Relevant clinical history Clinical diagnosis

Information related to research trials (where relevant)

Information related to pregnancy and breastfeeding (where appropriate)
Signature or e-signature Name and contact details of referrer for results, reports and any potential escalation
Expected Information
Clinical findings on examination Mobility status (e.g., requires a hoist)
Co-morbidities (where relevant) Medication
Desirable Information

Carer or comforter requirements or other relevant radiation protection information


Patients referred internally within UCLH will have images on PACS and reports available on EPIC once they are finalised.

External reports and images will be sent via Image Exchange Portal (IEP). Reports to GPs will be sent via DocMan.

A weekly check of data sends is performed by the nuclear medicine booking team in UCLH.

If you are concerned that reports or images have not been made available, please contact the booking team using the contacts given below.

Team Telephone Email
Booking 020 3447 0565
Duty Doctor
Duty Consultant

Referral guidelines for specific tests 

Please refer to the latest RCR referral guidelines for PET-CT imaging studies. The radiation exposure for common PET investigations is given in the table below.

Please note that whole-body PET-CT investigations also have an additional 8.4 mSv associated with the CT, where brain and heart imaging typically add a further 1 mSv of radiation exposure.

Radiopharmaceutical and Investigation Effective Dose Radiopharmaceutical and Investigation Effective Dose

Fluorodeoxyglucose (FDG) Whole body tumour imaging

7.6 mSv Fluorodeoxyglucose (FDG) Infection Imaging 7.6 mSv

Fluorodeoxyglucose (FDG) Dementia/Epilepsy Imaging

4.8 mSv Florbetaben Cerebral Amyloid Assessment 5.8 mSv

Fluoride (NaF) Bone Imaging

4.3 mSv Fluorodopa Congenital Hyperinsulinism 7 mSv

Rubidium Myocardial Perfusion Imaging

2.2 mSv Gallium Dotatate Somatostatin receptor Imaging 6.4 mSv

Gallium PSMA Prostate Imaging

4.6 mSv Fluorine PSMA Prostate Imaging 4.0 mSv

Referral to PET-MRI can be made through the same processes described above. For many indications listed for PET-CT, PET-MRI provides an alternative with lower radiation exposures because of the lack of CT irradiation – the PET radiation exposures are the same as those listed above.

PET-MRI may therefore be preferred where radiation exposure is particularly sensitive, such as in paediatric patients. Additional synergism between PET and more detailed MRI exists for some indications such as problem solving in neuro-oncology, head and neck cancer, multiple myeloma, hepatopancreatico-biliary and pelvic malignancies. These may be accommodated. Please leave contact details on referral and a member of our team would be in contact.

Please be aware however, that as with standard MR, safety screening for metal and electronic implants will be necessary. The device may also not be appropriate for patients who are claustrophobic.

Investigation Indications Patient Preparation Dose

Glomerular Filtration Rate (GFR)

  • Serial Monitoring of renal function
  • Pre and post chemotherapy
  • Pre and post renal transplant
  • Renal impairment
  • SLE
  • Diabetes melitus
  • None
0.05 mSv

Investigation Indications  Patient Preparation  Dose 
Bone scan 
  • Primary or metastatic tumours 

  • Trauma 

  • Sports injuries 

  • Avascular necrosis 

  • Infection 

  • Arthritis/facet joint disease 

  • Metabolic disorder 

  • Assessment of joint prosthesis 

  • Complex spine surgery 

  • Good hydration
2.9 mSv – 3.9 mSv + CT dose if SPECT-CT 
  • Differential diagnosis of movement disorders 

  • Differential diagnosis of dementia 

  • Assessment of PD disease severity 

  • Thyroid blockade >1 hour prior to injection 

  • List of medications needs to be provided 

4.6 mSv – 5.4 mSv 
DMSA (Kidney scan) 
  • Assessment of cortical scarring 

  • Divided renal function 

  • Detection of ectopic kidney 

  • Evaluation of renal transplant 

  • None 
0.7 mSv 
Gastric Emptying 
  • Suspected gastroparesis in diabetic patients 

  • After gastric surgery 

  • When taking medication that affects gastric motility 

  • Nil by mouth for 4 hours (inc. smoking) 

  • Certain drugs stopped two days prior to scan: 
    • Opiates 

    • Prokinetic agents 

    • Atropine, Nifedipine, Progesterone, Octreotide, Theopyline, Benzodiazepine, Phentolamine 

0.9 mSv 
Gastrointestinal bleed 
  • Evaluation of upper and lower gastrointestinal bleeding 
  • Contraindicated in patients receiving blood products 
4 mSv 
Hepatobiliary (HIDA) 
  • Acute cholecystitis 

  • Obstructive jaundice 

  • Detection of biliary leak after surgery or trauma 

  • Biliary atresia 

  • Duodeno-gastic reflux 

  • Nil by mouth for 6 hours 
2 mSv 
Lung V/Q scan 
  • Diagnosis of pulmonary embolism 

  • Assessment of regional ventilation and perfusion 

  • None 

  • A recent chest X-Ray (within 7 days) must be made available. 

1.5 mSv – 2.8 mSv 
MAG3 Kidney scan 
  • Divided renal function 

  • Assessment of outflow obstruction 

  • Urinary tract infection 

  • Renovascular disorders 

  • Evaluation of renal failure 

  • Renal transplant evaluation 

  • Captopril test in suspected renovascular hypotension 

  • Assessment of urinary bladder 

  • Good hydration 

  • For reflux studies, patient should be toilet trained 

  • For captopril studies, please contact the department 

0.7 mSv 
  • Meckel’s diverticulum 

  • Suspected ectopic gastric mucosa in children with bowel duplication 

  • Nil by mouth for 4-6 hours 

  • Infants may require sedation and nursing support 

  • A recent barium examination within 24 hours may obscure a small bleeding site so delay meckels scans until after this. 

5 mSv 
MIBG Scan 
  • Suspected neuroendocrine tumour 

  • Assessment of adrenal masses 

  • As a prelude to MIBG therapy 

  • Cardiac innervation 

  • Thyroid blockade >1 hour prior to injection 
5.2 mSv 
MUGA scan 
  • Assessment of left ventricular function before chemotherapy 

  • Monitoring cardiac effects of chemotherapy 

  • Evaluation of patients with dyspnoea who are poor echocardiography subjects 

  • None 
5.6 mSv 
  • Suspected parathyroid adenoma 
  • None 
8.1 mSv 
Sentinel Lymph Node 
  • Pre-operative localisation of the sentinel node 
  • Surgical team must discuss directly with department 
0.02 mSv – 
0.08 mSv 
  • Goitre and evaluation of palpable nodules 

  • Hyperthyroidism 

  • Thyroiditis 

  • Differential diagnosis of anterior neck masses 

  • Previous neck radiation 

  • As a prelude to radio-iodine therapy in thyrotoxic patients 

  • Thyroid medication should be stopped prior to tracer injection: 
    • Carbimazole: 2 weeks 

    • Propylthiouracil: 2 weeks 

    • T3: 2 weeks 

    • T4/thyroxine: 2 weeks 

  • No shellfish on day of an prior to test 

  • CT scans within 6/8 weeks

1.0 mSv 

Please note if patient is having a CT scan with contrast same day as this may affect the Bone Density images; in this case, the Bone Density must be done first.

Bone density cannot be done within 7 days of CT with contrast.

Investigation  Indications  Patient Preparation  Dose 
Hip and Lumbar Spine 
  • Diagnosis and serial assessment of osteoporosis 

  • Treatment Response 

  • 0.013 mSv (Spine) 
  • 0.009 mSv (Hip) 
Total Body Composition 
  • Evaluation of tissue, fat and bone mass 
None  0.004 mSv 

The department performs the following therapies: 

  • Iodine-131 therapy for benign thyroid conditions such as hyperthyroidism and euthyroid goitre 

  • Iodine-131 MIBG therapy for the treatment of MIBG avid neuroendocrine tumours and neuroblastoma 

  • Lutetium-177 therapy for somatostatin receptor positive neuroendocrine tumours and neuroblastoma 

  • Radium-223 treatment targeting bone metastases in castration-resistant prostate cancer 

  • Lutetium-177 therapy for metastatic castration-resistant prostate cancer (mCRPC) 

Referrals for all therapies should be made via discussion with the nuclear medicine department and be presented through the UCLH Molecular Radiotherapy MDT. 

Referral guidelines for other tests and radionuclide therapies, and specific referral information on the tests mentioned above are given in British Nuclear Medicine Society and European Association of Nuclear Medicine procedure guidelines.

These guidelines also provide information on radiation exposure associated with tests, which is also available from the UKHSAs ARSAC notes for guidance.