TABLE 1.

α-Emitters for Radiotherapy, Together with Their Decay Progeny

Parent	Daughters		t½	α-decay	α-energy (MeV)	Other emission	Radiochemistry	Free isotope accumulation	Study
211At*			7.2 h	42%	5.87		Tin precursor, prosthetic group	Thyroid, stomach, spleen, lung	(15)
	211Po		0.52 s	100%	7.45	Kα x-rays (77–92 keV)
	207Bi		38 y			100% electron capture
	207Po		Stable
225Ac*			9.9 d	100%	5.94		DOTA, DO3A chelator	Liver, bone	(21,56)
	221Fr†		4.9 m	100%	6.45	218 keV γ		Kidneys, urine
	217At		32.3 ms	>99.9%	7.20
	213Bi*†		45.6 m	2.2%	5.87	492 keV β− (97.8%); 440 keV γ	CHX-A″-DTPA, DOTA, NETA	Kidneys, urine	(50)
		213Po	3.72 μs	100%	8.38
		209Tl	2.16 m			660 keV β− (100%)
		209Pb	3.23 h			198 keV β− (100%)
		209Bi	Stable
227Th*			18.7 d	100%	6.14	50 and 236 keV γ	DOTA, Me-3,2-HOPO	Bone surface	(25)
	223Ra*		11.4 d	100%	5.71	269 keV γ		Bone surface	(57)
		219Rn	3.96 s	100%	6.82	271 keV γ
		215Po	1.78 ms	>99.9%	7.39
		211Pb†	36.1 m			471 keV β− (100%); 404 keV γ		Blood, liver, skeleton, kidneys	(58)
		211Bi†	2.14 m	99.7%	6.62	172 keV β− (0.3%); 351 keV γ		Kidneys, urine	(58)
		207Tl	4.77 m			492 keV β− (100%)
		207Pb	Stable
224Ra*			3.63 d	100%	5.69	241 keV γ		Bone surface	(30)
	220Rn†		55.6 s	100%	6.29
	216Po		0.15 s	100%	6.78
	212Pb*†		10.6 h			93.5 keV β− (100%); 238 and 300 keV γ	TCMC	Blood, liver, skeleton, kidneys	(31,32)
	212Bi*†		60.6 m	36%	6.05	834 keV β− (64%); 727 and 1,620 keV γ	CHX-A″-DTPA, DOTA, NETA	Kidneys, urine	(32)
		212Po	0.30 μs	100%	8.78
		208Tl	3.1 m			342, 441, 535, and 649 keV β− (100%); 2,614 keV γ
		208Pb	Stable

^*α-emitters of interest.

^†Daughters with redistribution potency.

DO3A = 2,2′,2′′-(1,4,7,10-tetraazacyclododecane-1,4,7-triyl)triacetate.