Construction of a convenient head phantom for BNCT experiments in Tehran research reactor E. Bavarnegin,Yaser Kasesaz, H. Khalafi Nuclear Science and Technology Research Institute, Iran I due argomenti trattati in questa tesina sono un breve review sulle motivazioni fisiche e la storia dell’adroterapia e una presentazione dei recenti progressi e delle nuove prospettive soprattutto in Italia.

BNCT – physical background Per capire cos’è l’adroterapia bisogna illustrare cos’è la radioterapia: essa consiste nell’irraggiare con radiazioni o particelle ionizzanti individui colpiti da tumore per inattivare o distruggere le cellule neoplastiche risparmiando per quanto possibile il tessuto sano circostante. Praticamente fino allo scorso decennio la terapia radiante era effettuata prevalentemente con fotoni (raggi X o raggi gamma) e più limitatamente con elettroni.

Prof. Mauro Valente - CONICET & Universidad Nacional de Cordoba BNCT beam parameters BNCT with epithermal neutron beam In air beam parameters BNCT with Thermal neutron beam Prof. Mauro Valente - CONICET & Universidad Nacional de Cordoba

TRR irradiation facilities - TRR is a 5 MW MTR (Material Test Reactor) - pool type research reactor - Its fuel assemblies contain low enriched uranium fuel - plates in the form of U3O8 Al alloy - The reactor pool has two major parts, a stall-end and an open pool. - The reactor core can operate in both parts of the pool for different purposes.

Prof. Mauro Valente - CONICET & Universidad Nacional de Cordoba Thermal column of Tehran research reactor is feasible for BNCT. Prof. Mauro Valente - CONICET & Universidad Nacional de Cordoba

Prof. Mauro Valente - CONICET & Universidad Nacional de Cordoba Dosimetry in BNCT BNCT beam parameters In phantom parameters The main purpose of phantom dosimetry is to measure the neutron and gamma fluence rate and absorbed dose distributions. Phantom dosimetry provides information, which can be used to verify a neutron beam. Advantage Depth (AD) Advantage Depth Dose Rate (ADDR) Therapeutic Time (TT) Therapeutic Gain (TG) Prof. Mauro Valente - CONICET & Universidad Nacional de Cordoba 6

Main dose components in BNCT Neutron reactions in tissue : Thermal Neutrons:   Epithermal and fast neutrons: 1H(n,)2H Gamma dose 14N(n,p)14C Nitrogen dose 10B(n,α)7Li Boron dose Elastic scattering mainly with H (backscattering p+ ) Per capire cos’è l’adroterapia bisogna illustrare cos’è la radioterapia: essa consiste nell’irraggiare con radiazioni o particelle ionizzanti individui colpiti da tumore per inattivare o distruggere le cellule neoplastiche risparmiando per quanto possibile il tessuto sano circostante. Praticamente fino allo scorso decennio la terapia radiante era effettuata prevalentemente con fotoni (raggi X o raggi gamma) e più limitatamente con elettroni. Fast neutron dose Prof. Mauro Valente - CONICET & Universidad Nacional de Cordoba

Prof. Mauro Valente - CONICET & Universidad Nacional de Cordoba BNCT phantom One of the requirements for BNCT at a nuclear research reactor is construction of a phantom and measurements of physical dose distribution, Off-axis profiles, etc. Therefore: We have designed and constructed a head phantom for BNCT experiments of Tehran research reactor Prof. Mauro Valente - CONICET & Universidad Nacional de Cordoba

Prof. Mauro Valente - CONICET & Universidad Nacional de Cordoba BNCT phantom Characteristics of our designed head phantom for TRR BNCT experiments The shape and dimension is close to a standard head model ( Snyder head model). The materials are neurotically similar to the tissue The design permits us the determination of all relevant doses at many location inside of the phantom. So the 3D dose- map can obtain. There are places for dosimetric devices like gold foils, TLD and … Prof. Mauro Valente - CONICET & Universidad Nacional de Cordoba

Design of TRR BNCT head phantom An ellipsoidal acrylic walled anthropomorphic head phantom. Dimensions are close to the Snyder head model. Prof. Mauro Valente - CONICET & Universidad Nacional de Cordoba

Design of TRR BNCT head phantom Acrylic base An acrylic base was attached to the shell of the phantom In order to insertion of detectors into the phantom volume, 31 ports were assumed in the phantom base. ports One port on the phantom center line and the others each on three concentric circles of 3.4, 6.2 and 9 cm diameter. Prof. Mauro Valente - CONICET & Universidad Nacional de Cordoba

Design of TRR BNCT head phantom point dose measurement devices, like ion chambers and gold foils can be held in position with an acrylic spacer at the end of tubes which can be inserted from the ports into the phantom volume. Water was chosen for the interior of the phantom. Place of TLDs and gold foils. Side view of the phantom Prof. Mauro Valente - CONICET & Universidad Nacional de Cordoba

Design of TRR BNCT head phantom Prof. Mauro Valente - CONICET & Universidad Nacional de Cordoba

MCNP geometry of designed phantom The thermal column of Tehran research reactor can be also a favorable facility for providing an epithermal neutron beam for BNCT.

Thermal neutron beam of TRR Prof. Mauro Valente - CONICET & Universidad Nacional de Cordoba

Prof. Mauro Valente - CONICET & Universidad Nacional de Cordoba

Prof. Mauro Valente - CONICET & Universidad Nacional de Cordoba

Prof. Mauro Valente - CONICET & Universidad Nacional de Cordoba Thermal column of TRR Prof. Mauro Valente - CONICET & Universidad Nacional de Cordoba

Prof. Mauro Valente - CONICET & Universidad Nacional de Cordoba

Prof. Mauro Valente - CONICET & Universidad Nacional de Cordoba

Prof. Mauro Valente - CONICET & Universidad Nacional de Cordoba

Prof. Mauro Valente - CONICET & Universidad Nacional de Cordoba Designed head phantom in front of the simulated epithermal neutron beam of TRR Tallies MCNP geometry, (1) Core, (2) Pb block, (3) Al-caned graphite box, (4) Moderator, (5) air filled collimator, (6) Pb Reflector, (7) Bi gamma shield, (8) Cd filter, (9) Designed phantom,(10) water,(11) acrylic. Prof. Mauro Valente - CONICET & Universidad Nacional de Cordoba

Prof. Mauro Valente - CONICET & Universidad Nacional de Cordoba In phantom parameters for simulated epithermal neutron beam of TRR Facility ADDR (cGy/min) AD (cm) TT (min) Tumor: normal tissue 10B concentration (ppm) THOR 50 8.9 25 65:18 FiR-1 45 9 30 R2-0 67 9.7 20 TRR 49 7.5 Prof. Mauro Valente - CONICET & Universidad Nacional de Cordoba

THANKS FOR YOUR KIND ATTENTION!!! Per capire cos’è l’adroterapia bisogna illustrare cos’è la radioterapia: essa consiste nell’irraggiare con radiazioni o particelle ionizzanti individui colpiti da tumore per inattivare o distruggere le cellule neoplastiche risparmiando per quanto possibile il tessuto sano circostante. Praticamente fino allo scorso decennio la terapia radiante era effettuata prevalentemente con fotoni (raggi X o raggi gamma) e più limitatamente con elettroni. Prof. Mauro Valente - CONICET & Universidad Nacional de Cordoba 24