title: 3'-deoxy-3'-[¹⁸F]fluorothymidine PET quantification of bone marrow response to radiation dose.
abstract: OBJECTIVE
  The purpose of this study was to quantify the relationship of bone marrow response to radiation dose, using 3'-deoxy-3'-[(18)F]fluorothymidine ([(18)F]FLT)-labeled uptake quantified in positron-emission tomography (PET) scans.
  
  
  METHODS
  Pre- and post-Week 1 treatment [(18)F]FLT PET images were registered to the CT images used to create the radiation treatment plan. Changes in [(18)F]FLT uptake values were measured using profile data of standardized uptake values (SUVs) and doses along the vertebral bodies located at a field border where a range of radiation doses were present for 10 patients. Data from the profile measurements were grouped into 1 Gy dose bins from 1 to 9 Gy to compare SUV changes for all patients. Additionally, the maximum pretreatment, the post-Week 1 treatment, and the dose values located within the C6-T7 vertebrae that straddled the field edge were measured for all patients.
  
  
  RESULTS
  Both the profile and the individual vertebral data showed a strong correlation between SUV change and radiation dose. Relative differences in SUVs between bins >1 Gy and <7 Gy were statistically significant (p < 0.01, two-sample t test). The reduction in SUV was approximately linear until it reached a reduction threshold of 75%-80% in SUV for doses greater than 6 Gy/week for both the dose-binned data and the vertebral maximum SUVs.
  
  
  CONCLUSIONS
  The change in SUV observed in head and neck cancer patients treated with chemoradiation shows the potential for using [(18)F]FLT PET images for identifying active bone marrow and monitoring changes due to radiation dose. Additionally, the change in [(18)F]FLT uptake observed in bone marrow for different weekly doses suggests potential dose thresholds for reducing bone marrow toxicity.
authors.affiliation: Department of Radiation Oncology, University of Iowa Hospitals and Clinics, Iowa City, Iowa 52242, USA. sarah-mcguire@uiowa.edu
authors.forename: Sarah M
authors.initials: SM
authors.lastname: McGuire
authors.forename: Yusuf
authors.initials: Y
authors.lastname: Menda
authors.forename: Laura L
authors.initials: LL
authors.lastname: Boles Ponto
authors.forename: Brandie
authors.initials: B
authors.lastname: Gross
authors.forename: John
authors.initials: J
authors.lastname: Buatti
authors.forename: John E
authors.initials: JE
authors.lastname: Bayouth
mesh_terms: D001853:Bone Marrow / Q000000981:diagnostic imaging* / Q000528:radiation effects*; D001854:Bone Marrow Cells / Q000166:cytology / Q000000981:diagnostic imaging / Q000528:radiation effects; D049109:Cell Proliferation / Q000528:radiation effects; D015224:Dideoxynucleosides; D004307:Dose-Response Relationship, Radiation; D005462:Fluorine Radioisotopes; D006258:Head and Neck Neoplasms / Q000532:radiotherapy*; D006801:Humans; D049268:Positron-Emission Tomography / Q000379:methods*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D014057:Tomography, X-Ray Computed
chemical_list: D015224:Dideoxynucleosides; D005462:Fluorine Radioisotopes; C002854:alovudine