Inclusion Criteria:

- Recipient, or recipient's parents, or recipient's legal guardians must have signed a
voluntary, informed consent in accordance with institutional and federal guidelines

- Must have histopathologically confirmed diagnosis in one of the followed categories:

- AML

- MDS with intermediate or high-risk disease

- ALL

- Children and adults at any age with significant morbidity, as determined by the
primary bone marrow transplant (BMT) doctor (MD), and approved by the principal
investigator (PI)

- Able to lie supine in a full body cast for approximately 30 minutes, the anticipated
duration of each treatment session; for younger patients deep conscious sedation may
be required

- Performance status evaluated by Zubrod or Karnofsky (KPS) Performance Scales in
patients > 16 years or Lanksy Performance Scale in children =< 16 years must have a
score >= 70%

- Adequate cardiac function: cardiac ejection fraction > 50% by multi gated acquisition
scan (MUGA) scan and/or by echocardiogram

- Adequate pulmonary function: adults (older than 16 years): diffusing capacity of
carbon monoxide (DLCO) > 50%; for young children in whom pulmonary function tests
(PFT) are not applicable: assessment by a pediatrician or pulmonary consult

- Adequate renal function as demonstrated by: creatinine clearance or glomerular
filtration rate (GFR) > 60 cc/min (24 hour urine collection)

- Serum glutamic oxaloacetic transaminase (SGOT) and serum glutamic pyruvic
transaminase (SGPT) =< 5.0 times the institutional upper limits of normal

- Patients must have less than 15% peripheral blasts

- Pre-treatment tests must have been preformed within 30 days prior to initiation of
high-dose chemotherapy

- No other medical and/or psychosocial problems, which in the opinion of the primary
physician or principle investigator would place the patient at unacceptable risk from
this regimen

Exclusion Criteria:

- Patients with Acute Undifferentiated Leukemia (AUL), i.e. no lymphoid or myeloid
markers

- Previous radiation therapy to more than 20% of bone marrow containing areas, or to
any area exceeding 2000 cGy

- Patients with Fanconi Anemia

- Major medical or psychiatric disorders that would seriously compromise patient
tolerance of this regimen

- Human immunodeficiency virus (HIV) infection

- Evidence of Hepatitis B or C infection or evidence of cirrhosis

- Uncontrolled viral, bacterial or fungal infection

- Patients with recent (within 4 weeks) serious viral, fungal, or bacterial infection
are excluded

- Patients with radiographic changes indicating pulmonary disease, including but not
limited to: pulmonary nodules, infiltrates, pleural effusion are excluded unless
cleared by pulmonary biopsy showing no evidence for active pulmonary disease