1. Division of Hematology/Oncology/Stem Cell Transplantation, Department of Pediatrics, Columbia University Medical Center, New York, New York
2. Unidad Nacional de Oncología Pediátrica, Guatemala City, Guatemala
3. International Agency for Research on Cancer, World Health Organization, Lyon, France
4. Tecniscan, Guatemala City, Guatemala
5. Department of Nuclear Medicine, McMaster University and Hamilton Health Sciences Corporation, Hamilton, Ontario, Canada
6. School of Medicine, Francisco Marroquín University, Guatemala
7. Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada