Table 4.

Approximate Radiation Effective Dose Associated with Selected SPECT, PET and CT Measures

Modality	Measurement	Compound	Approximate effective radiation dose (mSv)	Refs
SPECT	Ventilation	99mTc-DTPA	0.2	(216, 287)
SPECT	Ventilation	99mTc-Technegas	0.6	(287)
SPECT	Ventilation	133Xe	0.5	(216)
SPECT	Perfusion	99mTc-MAA	2.0	(216)
SPECT	Perfusion	81mKr	0.16	(255)
SPECT	${\dot{V}}_{\text{A}}/\dot{Q}$	133Xe	1.1	(287)
Dual isotope SPECT	${\dot{V}}_{\text{A}}/\dot{Q}$	99mTc-Technegas/113In	3.3	(285)
PET	Ventilation	68Ga-Galligas	1.1	(23)
PET	Perfusion	68Ga-MAA	3.6	(23)
PET	VA/Q	13N	0.2	(225)
CT	Attenuation	-	2.5	(23)
Dual energy CT	Ventilation	Xe	4.1–4.8	(146)
4DCT	Perfusion	Iodinated contrast	4.2	(95)
Dual energy CT	Perfused blood volume	Iodinated contrast	3.5	(95)

The approximate effective radiation dose for some types of imaging procedures. The effective radiation dose takes into account the sum of organ doses of a particular type of radiation exposure, which is a function of the type of radiation, and the duration of exposure. In the case of tracers, the half-life and rate of clearance, are also important. The effective radiation dose will vary with the individual and the exact imaging conducted.