Thesis

55 The EANM practice guideline for Bone Scintigraphy metaphyseal growth zones and this can give rise to absorbed doses in these areas which are larger than the average skeletal dose. In pathological cases with higher uptake in bone and with severely impaired or without renal clearance the absorbed doses to bone surfaces and bone marrow can increase by a factor of 2, resulting in an increase of the effective dose with approximately 12%. The effective dose for an adult is in the order of 3-4 mSv and in children 2.5 mSv (table 1). The additional dose by the CT is not taken into account in these figures. The effective dose by the CT depends strongly on the machine used: for a diagnostic scan of the hips and spine the effective dose can range between 4 and 10 mSv [57, 58]. The much lower mAs used for localization or attenuation correction CTs results in effective doses of maximally 3 mSv. The effective doses for both types of CT-scans to the extremities are all less than 0.1 mSv. Table 6. Absorbed dose to various organs in healthy subjects following administration of 99mTclabelled phosphates and phosphonates according to ICRP Publication 80. Absorbed dose per unit activity administered (mGy/MBq) Organ Adult 15 years 5 years Adrenals 0.0021 0.0027 0.0058 Bladder 0.048 0.060 0.073 Bone surfaces 0.063 0.082 0.22 Brain 0.0017 0.0021 0.0043 Breast 0.00071 0.00089 0.0022 Gall bladder 0.0014 0.0019 0.0042 Stomach 0.0012 0.0015 0.0035 Small intestine 0.0023 0.0029 0.0053 Colon 0.0027 0.0034 0.0061 Heart 0.0012 0.0016 0.0034 Kidneys 0.0073 0.0088 0.018 Liver 0.0012 0.0016 0.0036 Lungs 0.0013 0.0016 0.0036 Muscles 0.0019 0.0023 0.0044 Oesophagus 0.0010 0.0013 0.0030 Ovaries 0.0036 0.0046 0.0070 Pancreas 0.0016 0.0020 0.0045 Red marrow 0.0092 0.010 0.033 Skin 0.0010 0.0013 0.0029 Spleen 0.0014 0.0018 0.0045 2

RkJQdWJsaXNoZXIy MjY0ODMw