Table 1.

Dose Escalation Schema

Toxicity Level	Red Marrow Index (Gy)*	MIBG Dose (mCi/kg)
		1	2	Cumulative
1	4.0	12	†	∼24
2	6.0	15	†	∼30
3	8.0	18	†	∼36
4	8.0	21	≤ 21	∼42

Abbreviation: MIBG, metaiodobenzylguanidine.

^*Red marrow index was calculated from the whole body dose.

^†All second doses were adjusted such that the desired cumulative whole body dose was delivered, but an amendment for level 4 mandated by the US Food and Drug Administration restricted dose 2 so that it would not exceed dose 1.