The purpose of this study is to develop blood tests and urine tests that can tell doctors how much radiation a person has been exposed to. Doctors know how much radiation patients are exposed to in certain medical situations. An example of this would be radiation treatment for cancer. Radiation treatment machines are programmed to give exact doses of radiation.

MSKCC patients undergoing TBI as part of a hematopoietic stem cell transplant (HSCT) will have blood drawn and urine collected for use in the validation and refinement of new methods for rapid high-throughput radiation biodosimetry. These blood and urine samples will be collected before, and at defined times after TBI. Blood sampling will occur in the same manner that it does during routine patient care during HSCT.

Inclusion Criteria:

• Patients greater than 4 years of age at Memorial Sloan-Kettering Cancer Center
• Must be undergoing hematopoietic stem cell transplantation (either autologous or allogenic) in conjunction with a conditioning regimen that includes TBI (single or multiple fraction)
• Functional central venous catheter

Exclusion Criteria:

• No subjects will be excluded from the proposed research study for demographic reasons. Treatment with growth factors, such as keratinocyte growth factor (KGF), will not be grounds for exclusion.
• Subjects who will receive radiation therapy within 5 days prior to TBI will be excluded.
• Subjects who will receive systemic antineoplastic chemotherapy within 7 days prior to TBI not have research bloods collected. Only urine will be collected from these patients.
• Based on current knowledge, we will not a priori exclude patients based on disease status (ie, patients in or out of remission will be included in this study), type of disease(ie, chromosomal breakage syndromes), or previous therapies (unless exclusion criteria is met).

Potential research subjects will be identified by the primary Radiation Oncologist whom the patient is referred to by the Adult or Pediatric Bone Marrow Transplant Service.