title: Calculations of dose distributions in the lungs of a rat model irradiated in the thermal column of the TRIGA reactor in Pavia.
abstract: To test the possibility to apply boron neutron capture therapy (BNCT) to lung tumors, some rats are planned to be irradiated in the thermal column of the TRIGA reactor of the University of Pavia. Before the irradiation, lung metastases will be induced in BDIX rats, which will be subsequently infused with boronophenylalanine (BPA). During the irradiation, the rats will be positioned in a box designed to shield the whole animal except the thorax area. In order to optimize the irradiation set-up and to design a suitable shielding box, a set of calculations were performed with the MCNP Monte Carlo transport code. A rat model was constructed using the MCNP geometry capabilities and was positioned in a box with walls filled with lithium carbonate. A window was opened in front of the lung region. Different shapes of the holder and of the window were tested and analyzed in terms of the dose distribution obtained in the lungs and of the dose absorbed by the radiosensitive organs in the rat. The best configuration of the holder ensures an almost uniform thermal neutron flux inside the lungs (Phi(max)/Phi(min)=1.5), an irradiation time about 10 min long, to deliver at least 40 Gy(w) to the tumor, a mean lung dose of 5.9+/-0.4 Gy(w), and doses absorbed by all the other healthy tissues below the tolerance limits.
authors.affiliation: Department of Nuclear and Theoretical Physics, University of Pavia, Via Bassi, 6, Pavia, Italy. nicoletta.protti@pv.infn.it
authors.forename: N
authors.initials: N
authors.lastname: Protti
authors.forename: S
authors.initials: S
authors.lastname: Bortolussi
authors.forename: S
authors.initials: S
authors.lastname: Stella
authors.forename: M A
authors.initials: MA
authors.lastname: Gadan
authors.forename: A
authors.initials: A
authors.lastname: De Bari
authors.forename: F
authors.initials: F
authors.lastname: Ballarini
authors.forename: P
authors.initials: P
authors.lastname: Bruschi
authors.forename: C
authors.initials: C
authors.lastname: Ferrari
authors.forename: A M
authors.initials: AM
authors.lastname: Clerici
authors.forename: C
authors.initials: C
authors.lastname: Zonta
authors.forename: J G
authors.initials: JG
authors.lastname: Bakeine
authors.forename: P
authors.initials: P
authors.lastname: Dionigi
authors.forename: A
authors.initials: A
authors.lastname: Zonta
authors.forename: S
authors.initials: S
authors.lastname: Altieri
mesh_terms: D000818:Animals; D016754:Boron Neutron Capture Therapy / Q000295:instrumentation* / Q000706:statistics & numerical data*; D007558:Italy; D008175:Lung Neoplasms / Q000532:radiotherapy* / Q000556:secondary; D023421:Models, Animal; D009010:Monte Carlo Method; D009688:Nuclear Reactors; D019047:Phantoms, Imaging; D011835:Radiation Protection / Q000295:instrumentation; D011880:Radiotherapy Planning, Computer-Assisted / Q000706:statistics & numerical data*; D051381:Rats; D012062:Relative Biological Effectiveness