DISEASE CHARACTERISTICS:

• Histologically or cytologically confirmed malignant neoplasm

  • Not amenable to standard therapy or has failed existing first- and second-line therapies
• Tumor positive for somatostatin receptors by OctreoScan within the past 4 weeks

• At least 1 measurable lesion

  • Lesions that have been previously irradiated must demonstrate progression since radiation
  • At least 1 measurable somatostatin receptor-positive lesion that has not been irradiated within the past 4 weeks AND has not had full craniospinal radiation within the past 3 months
• Bone marrow with at least 40% cellularity OR at least 20% cellularity with one million CD34+ stem cells/kg stored
• No diffuse bone marrow involvement by OctreoScan scintigraphy

PATIENT CHARACTERISTICS:

Age

• 2 to 25

Performance status

• COG 0-2 OR
• Karnofsky 60-100% OR
• Lansky 60-100%

Life expectancy

• 2-12 months

Hematopoietic

• See Disease Characteristics
• Absolute neutrophil count at least 1,000/mm^3
• Platelet count at least 100,000/mm^3

Hepatic

• Bilirubin less than 1.5 times normal
• AST and ALT less than 2.5 times upper limit of normal

Renal

• Creatinine no greater than 1 mg/dL (children less than 5 years of age)
• Creatinine less than 1.2 mg/dL (children 5 to 10 years of age)
• Creatinine less than 1.7 mg/dL (children over 10 years of age) AND
• Glomerular filtration rate at least 80 mL/min/m^2

Cardiovascular

• Shortening fraction at least 28% by echocardiogram
• Ejection fraction at least 50% by bi-plane method of echocardiogram
• No prior congestive heart failure unless ejection fraction at least 40%
• No unstable angina pectoris
• No cardiac arrhythmia
• No symptomatic congestive heart failure

Other

• No other concurrent malignancy
• No other significant uncontrolled medical, psychiatric, or surgical condition that would preclude study compliance
• No antibodies to yttrium Y 90-DOTA-tyr3-octreotide or octreotide
• No prior allergic reactions to compounds of similar chemical or biologic composition to yttrium Y 90-DOTA-tyr3-octreotide
• No ongoing or active infection
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception during and for 6 months after study participation

PRIOR CONCURRENT THERAPY:

Biologic therapy

• Not specified

Chemotherapy

• At least 4 weeks since prior chemotherapy (6 weeks for nitrosoureas or mitomycin)

Endocrine therapy

• More than 28 days since prior long-acting somatostatin analogues
• No concurrent somatostatin analogues 12 hours before or 12 hours after study drug administration
• Concurrent hormonal therapy (other than somatostatin analogue) allowed provided patient received hormonal therapy for at least 2 months and has stable disease or progressive disease

Radiotherapy

• See Disease Characteristics
• At least 4 weeks since prior radiotherapy
• No prior radiotherapy to 25% or more of bone marrow
• No prior external beam radiotherapy to both kidneys (scatter doses of less than 500 cGy to a single kidney or radiation to less than 50% of a single kidney is allowed)

Surgery

• At least 4 weeks since prior surgery

Other

• Recovered from prior therapy
• At least 4 weeks since prior investigational drugs
• No other concurrent approved or investigational anti-neoplastic therapies except for bisphosphonates
• No concurrent combination antiretroviral therapy for HIV-positive patients