Table 1.

Brachytherapy source spectra used for MC calculations. ¹²⁵I gamma ray spectral data for seed and bare sources are from Chen and Nath (2001) and Dillman and Von der Lage (1975), respectively. ¹⁶⁹Yb gamma ray spectral data are from Medich et al (2006).

125I (Seed) half-life: 59.4 days		125I (Bare) half-life: 59.4 days		169Yb half-life: 32.0 days
Energy (keV)	Relative intensity	Energy (keV)	Relative intensity	Energy (keV)	Relative intensity
22.1	0.25	3.7	0.2226	49.5	0.532
25.2	0.07	27.2	0.3906	50.7	0.940
27.4	1.00	27.4	0.7615	57.6	0.295
31.4	0.25	30.9	0.2056	59.1	0.082
35.5	0.06	31.8	0.0426	63.1	0.442
		35.4	0.0666	93.6	0.026
				109.8	0.175
				118.2	0.019
				130.5	0.113
				177.2	0.222
				198.0	0.358
				261.1	0.017
				307.7	0.101