Rituximab, Yttrium Y 90 Ibritumomab Tiuxetan in Patients W/Relapsed Stage II, III, or IV Follicular NHL

250 mg/m2/day IV over 1 hour days 1,2,3,4 every 28 days for 2 cycles. If bone marrow \<25% involved and expected biodistribution after 2 cycles yttrium-90-ibritumomab tiuxetan (Zevalin) to be administered.

40 mg/day IV over 1 hour days 1,2,3,4 every 28 days for 2 cycles. If bone marrow \<25% involved and expected biodistribution after 2 cycles yttrium-90-ibritumomab tiuxetan (Zevalin) to be administered.

2000 mg/m2 IV over 2 hours days 4 every 28 days for 2 cycles. If bone marrow \<25% involved and expected biodistribution after 2 cycles yttrium-90-ibritumomab tiuxetan (Zevalin) to be administered.

25 mg/m2/day IV at 1mg/min days 1,2,3,4 every 28 days for 2 cycles. If bone marrow \<25% involved and expected biodistribution after 2 cycles yttrium-90-ibritumomab tiuxetan (Zevalin) to be administered.

250 mg/m2 slow IV over days 1, then 7,8 or 9 prior to In Zevalin. Rituximab + Zevalin regimen is given 4-6 weeks after completion of 2 cycles of ESHAP. Treatment can be completed within 7-9 days in an outpatient setting.

5 mCi slow IV push over 10 minutes days 1. Given within 4 hours after Rituximab.

Platelet counts from 100,000/mm3 to 149,000/mm3 will receive 0.3 mCi/kg. Platelet counts from \>/= 150,000/mm3 will receive 0.4 mCi/kg, not to exceed 32 mCi Y Zevalin. Slow IV push over 10 minutes, days 7,8 or 9 given within 4 hours after Rituximab.