title: Measurements of secondary neutron dose from 15 MV and 18 MV IMRT.
abstract: Secondary neutron dose-equivalents were determined for conventional and intensity modulated radiation therapy (IMRT) prostate treatments for 15 and 18 MV X-ray beams. Conventional and IMRT treatment plans were generated to deliver 45 Gy to the prostate, seminal vessicles and external and internal iliac lymph nodes. Neutron spectra were determined by unfolding measurements from a TLD-based Bonner sphere system. Treatments using 18 MV IMRT and conventional plans result in neutron ambient dose-equivalents of 687 and 112 mSv, respectively. Delivery of the 15 MV IMRT and conventional plans results in neutron ambient dose-equivalents of 327 and 52 mSv, respectively. The data illustrate that using lower photon energies for IMRT reduces the secondary neutron dose, while still achieving comparable treatment volume coverage and sparing critical normal tissue.
authors.affiliation: Department of Radiation Oncology, Emory University, 1365 Clifton Road, NE, Atlanta, GA 30322, USA. Rebecca@radonc.emory.org
authors.forename: Rebecca M
authors.initials: RM
authors.lastname: Howell
authors.forename: Michele S
authors.initials: MS
authors.lastname: Ferenci
authors.forename: Nolan E
authors.initials: NE
authors.lastname: Hertel
authors.forename: Gary D
authors.initials: GD
authors.lastname: Fullerton
authors.forename: Timothy
authors.initials: T
authors.lastname: Fox
authors.forename: Lawrence W
authors.initials: LW
authors.lastname: Davis
mesh_terms: D001822:Body Burden; D003198:Computer Simulation; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D018499:Linear Energy Transfer; D008954:Models, Biological; D009502:Neutrons; D011832:Radiation Injuries / Q000209:etiology / Q000517:prevention & control*; D011835:Radiation Protection / Q000379:methods*; D011874:Radiometry / Q000379:methods*; D011879:Radiotherapy Dosage; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects* / Q000379:methods*; D012062:Relative Biological Effectiveness; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors