title: Dynamic metabolic changes during the first 3 months after 90Y-ibritumomab tiuxetan radioimmunotherapy.
abstract: OBJECTIVE
  To elucidate the time course of tumor metabolism during the first 3 months after (90)Y-ibritumomab tiuxetan radioimmunotherapy (RIT) in patients with refractory malignant lymphoma.
  
  
  METHODS
  Seven patients with recurrent follicular lymphoma underwent FDG-PET imaging before and after 1-, 4-, and 12-week RIT with (90)Y-ibritumomab tiuxetan. Tumor metabolic activity on FDG-PET scans was assessed as the maximum standard uptake value (SUVmax).
  
  
  RESULTS
  Decrease in metabolism was detected 1 week after RIT. In the most decreased lesion, SUVmax decreased to 20% of the baseline value during the first week. Most lesions continued to decrease for up to 4 weeks. Some lesions showed increased metabolism from 4 to 12 weeks, while the level of FDG accumulations at 12 weeks was still lower than the baseline.
  
  
  CONCLUSIONS
  Tumor response to RIT could be observed as early as 1 week after the administration of RIT. After tumor activity decreases, the metabolism may increase at least between 4 and 12 weeks. It suggests that the metabolic changes should be carefully evaluated during this period.
authors: Department of Radiology, Graduate School of Medicine, The University of Tokyo, 3-1 Hongo 7-Chome, Bunkyo-ku, Tokyo 113-8655, Japan.
authors: Miwako
authors: 0000-0002-3325-8601
authors: M
authors: Takahashi
authors: Department of Radiology, Graduate School of Medicine, The University of Tokyo, 3-1 Hongo 7-Chome, Bunkyo-ku, Tokyo 113-8655, Japan.
authors: Toshimitsu
authors: 0000-0002-7566-400X
authors: T
authors: Momose
authors: Department of Radiology, Graduate School of Medicine, The University of Tokyo, 3-1 Hongo 7-Chome, Bunkyo-ku, Tokyo 113-8655, Japan.
authors: Keitaro
authors: K
authors: Koyama
authors: Department of Hematology and Oncology, Graduate School of Medicine, The University of Tokyo, 3-1 Hongo 7-Chome, Bunkyo-ku, Tokyo 113-8655, Japan.
authors: Motoshi
authors: 0000-0001-6497-0848
authors: M
authors: Ichikawa
authors: Department of Hematology and Oncology, Graduate School of Medicine, The University of Tokyo, 3-1 Hongo 7-Chome, Bunkyo-ku, Tokyo 113-8655, Japan.
authors: Mineo
authors: M
authors: Kurokawa
authors: Department of Radiology, Graduate School of Medicine, The University of Tokyo, 3-1 Hongo 7-Chome, Bunkyo-ku, Tokyo 113-8655, Japan.
authors: Kuni
authors: K
authors: Ohtomo
mesh_terms: D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal / Q000008:administration & dosage*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D009369:Neoplasms / Q000175:diagnosis / Q000378:metabolism* / Q000532:radiotherapy*; D049268:Positron-Emission Tomography; D016499:Radioimmunotherapy; D013997:Time Factors
chemical_list: D000911:Antibodies, Monoclonal; D019788:Fluorodeoxyglucose F18; C422802:ibritumomab tiuxetan