NAC459.3235. Quality factors for converting absorbed dose to dose equivalent.

     1. Except as otherwise provided in subsection 2, the quality factors for converting an absorbed dose to a dose equivalent are as follows:

Quality Factors and Absorbed Dose Equivalencies
Type of Radiation	Quality Factor		Absorbed Dose Equal to a Unit Dose Equivalent
X, gamma, or beta radiation and high-speed electrons........................................................ 1		1
Alpha particles, multiple-charged particles, fission fragments and heavy particles of unknown charge........................................................... 20		0.05
Neutrons of unknown energy............................ 10		0.1
High-energy protons.......................................... 10		0.1

     2. If it is more convenient to measure the neutron fluence rate than to determine the neutron dose equivalent rate in rems per hour, as provided in subsection 1, 1 rem of neutron radiation of unknown energies may, for the purposes of NAC 459.010 to 459.950, inclusive, be assumed to result from a total fluence of 25,000,000 neutrons per square centimeter incident upon the body. If sufficient information exists to estimate the approximate energy distribution of the neutrons, the licensee or registrant may use the fluence rate per unit dose equivalent or the appropriate quality factor value from the following table to convert a measured tissue dose in rads to dose equivalent in rem:

Mean Quality Factors and Fluence per Unit Dose Equivalent for Monoenergetic Neutrons
	Neutron Energy	Quality Factor	Fluence per Unit Dose Equivalent
	(MeV)		(neutrons
			cm2 rem-1)
(thermal)	2.5E-8	2	980E+6
	1E-7	2	980E+6
	1E-6	2	810E+6
	1E-5	2	810E+6
	1E-4	2	840E+6
	1E-3	2	980E+6
	1E-2	2.5	1010E+6
	1E-1	7.5	170E+6
	5E-1	11	39E+6
	1	11	27E+6
	2.5	9	29E+6
	5	8	23E+6
	7	7	24E+6
	10	6.5	24E+6
	14	7.5	17E+6
	20	8	16E+6
	40	7	14E+6
	60	5.5	16E+6
	1E+2	4	20E+6
	2E+2	3.5	19E+6
	3E+2	3.5	16E+6
	4E+2	3.5	14E+6

     3. For the purposes of subsection 2, the quality factor must be measured at the point where the dose equivalent is maximum in a 30-centimeter diameter cylinder tissue-equivalent phantom.

     (Added to NAC by Bd. of Health, eff. 1-18-94; A by R084-98, 1-26-99; R085-06, 11-13-2006; R149-07, 1-30-2008)