Effective Dose Equivalent and Effective Dose
Historically, the whole-body dose or total body dose was used to evaluate
the relative radiation risks of different procedures involving radiations. This
quantity is calculated according to the MIRD method by using the Sfactor
for the whole body as the source organ as well as the target organ. This
value does not take into consideration the effect of tissue sensitivity to
radiation.
In 1977 the ICRP introduced the concept of effective dose equivalent
(EDE) to take into account the different sensitivity of tissues to radiation
(ICRP 26). The tissues weighting factor (WT) for an organ was defined as
the ratio of the whole-body dose, which would cause a certain probability
of cancer induction to the absorbed dose in that organ which would cause
220 14. Internal Radiation Dosimetry
Table14.4.Continued
Dose
Radiopharmaceuticals Organ rad/mCi mGy/GBq
Kidneys 0.065 17.6
Ovaries 0.032 8.6
Liver 0.019 5.1(^89) Sr-strontium chloride (Metastron) Bone surfaces 63.0 17000.0
Red marrow 40.7 11000.0
Lower bowel 17.4 4700.0
Bladder wall 4.8 1300.0
Ovaries 2.9 800.0
Kidneys 2.9 800.0
(^90) Y-ibritumomab tiuxetan (Zevalin)† Spleen 27.2 7350.0
Liver 16.0 4320.0
Lungs 7.6 2050.0
Bladder wall 3.3 890.0
Red marrow 2.2 590.0
Kidneys 0.8 220.0
Other organs 1.5 400.0
(^123) I-tositumomab (Bexxar) Thyroid 10.027 2710.0
Kidneys 7.252 1960.0
Upper large intestine 4.958 1340.0
Heart wall 4.625 1250.0
Red marrow 2.405 650.0
Bladder wall 2.368 640.0
Ovaries 0.925 250.0
Brain 0.481 130.0
Total Body 0.888 240.0
(^133) Xe-xenon Lungs 0.008 2.2
- From Stabin MG, Stubbs JB, Toohey RE. Radiation dose estimates for radiopharmaceuti-
cals. Radiation Internal Dose Information Center, Oak Ridge Institute for Science and Foun-
dation, 1996.
†From Wiseman GA, Kormehl E, Leigh B, et al. Radiation dosimetry results and safety cor-
relations from^90 Y-ibritumomab tiuexetan radioimmunotherapy for relapsed or refractory non-
Hodgkin’s lymphoma. Combined data from four (4) clinical trials.J Nucl Med2003; 44:465.