construction of a convenient head phantom for bnct experiments in tehran research reactor e....

Construction of a Construction of a convenient head phantom convenient head phantom for BNCT experiments in for BNCT experiments in Tehran research reactorTehran research reactorE. Bavarnegin,Yaser Kasesaz, H. Khalafi

Nuclear Science and Technology Research Institute, Iran

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BNCT – physical backgroundBNCT – physical background

Prof. Mauro Valente - CONICET & Universidad Nacional de Cordoba

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In air beam parametersIn air beam parameters

BNCT beam parametersBNCT beam parameters

910120100 13102 13102 910120100 13102 13102

BNCT with Thermal neutron beamBNCT with Thermal neutron beam

BNCT with epithermal neutron beamBNCT with epithermal neutron beam

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TRR irradiation facilities TRR irradiation facilities

- TRR is a 5 MW MTR (Material Test Reactor)- TRR is a 5 MW MTR (Material Test Reactor)

- The reactor core can operate in both parts of the pool - The reactor core can operate in both parts of the pool for different purposes. for different purposes.

- pool type research reactor- pool type research reactor

- Its fuel assemblies contain low enriched uranium fuel- Its fuel assemblies contain low enriched uranium fuel

- plates in the form of U3O8 Al alloy- plates in the form of U3O8 Al alloy

- The reactor pool has two major parts, a stall-end and - The reactor pool has two major parts, a stall-end and an open pool.an open pool.


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Thermal column of Tehran research reactor is feasible for BNCT.


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Dosimetry in BNCTDosimetry in BNCT

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In phantom parametersIn phantom parameters

BNCT beam parametersBNCT beam parameters

Advantage Depth (AD)Advantage Depth (AD)

Advantage Depth Dose Rate (ADDR)Advantage Depth Dose Rate (ADDR)

Therapeutic Time (TT) Therapeutic Time (TT)

Therapeutic Gain (TG)Therapeutic Gain (TG)

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.


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Main dose components in BNCTMain dose components in BNCT

Neutron reactions in tissue :Neutron reactions in tissue :

Thermal NeutronsThermal Neutrons::

Epithermal and fast neutrons:Epithermal and fast neutrons:

11H(n,H(n,))22HH Gamma doseGamma dose1414N(n,p)N(n,p)1414CC Nitrogen doseNitrogen dose

1010B(n,B(n,αα))77LiLi Boron doseBoron dose

Elastic scattering mainly with H Elastic scattering mainly with H ((backscattering backscattering pp++ ) )

Fast neutron doseFast neutron dose


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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 We have designed and constructed a head phantom for BNCT experiments of Tehran research reactor experiments of Tehran research reactor

BNCT phantom BNCT phantom


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Characteristics of our designed head phantom for Characteristics of our designed head phantom for TRR BNCT experimentsTRR 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 …

BNCT phantom BNCT phantom


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An ellipsoidal acrylic walled An ellipsoidal acrylic walled anthropomorphic head phantom. anthropomorphic head phantom.

Dimensions are close to the Snyder head model.Dimensions are close to the Snyder head model.

Design of TRR BNCT head phantomDesign of TRR BNCT head phantom


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In order to insertion of detectors into the phantom volume, 31 ports were assumed in the phantom base.

One port on the phantom center line and the others each on three concentric circles of 3.4, 6.2 and 9 cm diameter.

Acrylic baseAn acrylic base was attached to the shell of the phantom

ports


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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



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MCNP geometry of designed phantomMCNP 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.


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Thermal neutron beam of TRRThermal neutron beam of TRR


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Thermal column of TRRThermal column of TRR


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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.

TalliesDesigned head phantom in front of the simulated Designed head phantom in front of the simulated epithermal neutron beam of TRR epithermal neutron beam of TRR


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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 65:18

R2-0 67 9.7 20 65:18

TRR 49 7.5 25 65:18

In phantom parameters for simulated epithermal neutron beam of TRR


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THANKS FOR YOUR KIND ATTENTION!!!

construction of a convenient head phantom for bnct experiments in tehran research reactor e....

Documents

phantom base

phantom ports

designed head phantom

convenient head phantom

phantom volume

thermal neutron beam

bnct physical background

bnct neutron reactions