This is a pilot study with the primary aim being to identify the minimum number of scans and measurements necessary to determine accurately the absorbed radiation doses delivered from internal sources of radiation administered for diagnostic nuclear medicine procedures.

A study to develop practical methods of accurate low radiation absorbed dose measurement in patients referred for nuclear medicine scans.

There is currently very little information on and therefore understanding of the effects of exposure to low levels of radiation on patients or radiation workers. Assumptions are largely based on evidence from high radiation doses following nuclear incidents which may not be applicable to medical procedures. Underestimation of the radiation effects incurs greater risk to patients than is currently assumed, while overestimation can prevent more informative scans that would be obtained from higher administered activities. This research study answers an invitation from the Department of Health Policy research programme to improve our understanding of those low radiation dose risks.

Over 600,000 patients have nuclear medicine scans in the UK each year, presenting an opportunity to accurately measure low radiation doses and follow up the effects on a large number of patients. This study will develop practical methods to measure accurately the radiation doses delivered to patients referred for nuclear medicine positron emission tomography (PET) and single photon emission computed tomography (SPECT) scans.

Five patients referred for each of 7 diagnostic nuclear medicine procedures will undergo up to 7 quantitative PET/SPECT scans and up to 10 whole body radiation retention measurements over the course of 1-2 days to enable the absorbed radiation doses to be calculated accurately. Analysis of subsets of these measurements will be performed to identify the timing and minimum number of measurements necessary for accurate dose estimates.

The longer term aim is that these methods and results will subsequently be used to inform a national epidemiological (epidemiology is the study of factors affecting the health and illness of populations) study on the effects of low doses of radiation.

Inclusion Criteria:

* All patients able to undergo the procedures necessary to acquire sufficient data for dosimetry, consisting of up 7 nuclear medicine scans and 10 external radiation retention measurements over a time period of up to 24 hours

Exclusion Criteria:

• Patients unable or unwilling to undergo further procedures that may include scans and external retention measurements.
• Paediatric patients 18 years of age and under.
• Pregnant patients.

Royal Marsden Hospital patients undergoing diagnostic nuclear medicine procedures to assess bone marrow involvement, kidney function, thyroid function, staging of adult malignancies and glucose metabolism.