title: 131I-tositumomab myeloablative radioimmunotherapy for non-Hodgkin's lymphoma:  radiation dose to the testes.
abstract: OBJECTIVE
  To investigate radiation doses to the testes delivered by a radiolabeled anti-CD20 antibody and its effects on male sex hormone levels.
  
  
  METHODS
  Testicular uptake and retention of (131)I-tositumomab were measured, and testicular absorbed doses were calculated for 67 male patients (54 ± 11 years of age) with non-Hodgkin's lymphoma who had undergone myeloablative radioimmunotherapy (RIT) using (131)I-tositumomab. Time-activity curves for the major organs, testes, and whole body were generated from planar imaging studies. In a subset of patients, male sex hormones were measured before and 1 year after the therapy.
  
  
  RESULTS
  The absorbed dose to the testes showed considerable variability (range = 4.4-70.2 Gy). Pretherapy levels of total testosterone were below the lower limit of the reference range, and post-therapy evaluation demonstrated further reduction [4.6 ± 1.8 nmol/l (pre-RIT) vs. 3.8 ± 2.9 nmol/l (post-RIT), P<0.05]. Patients receiving higher radiation doses to the testes (≥ 25 Gy) showed a greater reduction [4.7 ± 1.6 nmol/l (pre-RIT) vs. 3.3 ± 2.7 nmol/l (post-RIT), P<0.05] compared with patients receiving lower doses (<25 Gy), who showed no significant change in total testosterone levels.
  
  
  CONCLUSIONS
  The testicular radiation absorbed dose varied highly among individual patients. Patients receiving higher doses to the testes were more likely to show post-RIT suppression of testosterone levels.
authors.affiliation: aDepartment of Radiology, Division of Nuclear Medicine, University of Washington bFred Hutchinson Cancer Research Center, Seattle cPacific Northwest National Laboratory, Richland, Washington, USA.
authors.forename: Naoya
authors.initials: N
authors.lastname: Hattori
authors.forename: Ajay K
authors.initials: AK
authors.lastname: Gopal
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Shields
authors.forename: Darrell R
authors.initials: DR
authors.lastname: Fisher
authors.forename: Ted
authors.initials: T
authors.lastname: Gooley
authors.forename: John M
authors.initials: JM
authors.lastname: Pagel
authors.forename: Oliver W
authors.initials: OW
authors.lastname: Press
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Rajendran
mesh_terms: D055011:Ablation Techniques / Q000009:adverse effects*; D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal / Q000009:adverse effects* / Q000493:pharmacokinetics / Q000627:therapeutic use; D001853:Bone Marrow / Q000528:radiation effects*; D012739:Gonadal Steroid Hormones / Q000378:metabolism; D006801:Humans; D008228:Lymphoma, Non-Hodgkin / Q000378:metabolism / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D058958:Organs at Risk / Q000528:radiation effects; D011829:Radiation Dosage; D016499:Radioimmunotherapy / Q000009:adverse effects*; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D013737:Testis / Q000378:metabolism / Q000528:radiation effects*
chemical_list: D000911:Antibodies, Monoclonal; D012739:Gonadal Steroid Hormones; C119496:tositumomab I-131