6804

6346

كارشناسي ارشد

فيزيك هسته اي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده فيزيك

1390

يازده،114ص.: مصور﴿رنگي﴾،جدول،نمودار

ص.ع.به فارسي و انگليسي

احمد شيراني

محمدحسن علامت ساز

12/4/91

اكبر پروازيان،ظفرا... كلانتري

فيزيك

ID6346

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

AbstractProton therapy is one of the efficient methods in both control and treatment of patients withcancerous tumors Protons like other heavy charged particles lose almost all their energy nearthe end of their range Therefore it is possible to cover tumor s volume with high radiation dosewithout any side effects in healthy surrounded tissues In proton therapy calculations it isimportant to investigate nuclear interactions by proton beams with the atomic nuclei of thestopping materials specially human body In this project using MCNPX 2 6 0 code we haveinvestigated nuclear interactions of proton beams of energies of 250 300 and 500 MeV withusing f8 tally and adding ft8 res special treatment tally in human body and have determinatedboth type and amount of many various isotops which are produced as a result of nuclearinteractions of protons with elemental components of soft and hard tissues Our results arecompared with previous works in which semiemprical cross sections for nuclear interactions ofprotons have been used In addition it has been found that about 20 of the incident protons inthese energy ranges are absorbed by the human body via non elastic nuclear interactions andthe rest of protons pass through the body while losing a fraction of their energy via ionizationand excitation the atomic target nuclei In this work we report results of computer simulation andcalculation of nuclear interactions by protons In MCNPX 2 6 0 code library files of protoninteraction LA150H and ENDF70 prot include nuclear cross section data in low energies Alsotumors are treated with protons in 60 250MeV energy ranges So proton nuclear interactionswith 60 200MeV energy with elemental components of soft and hard tissues are investigated forbeams wich compeletely stop through human body and both type and amount of many variousproduced isotops have been determinate One important feature of proton therapy is that itproduces a small amount of positron emitting radioisotopes along the beam path through thenon elastic nuclear interaction of protons with target nuclei such as 12C 14N and 16O present inbody tissues These radioisotopes mainly 11C 13N and 15O allow imaging the therapy dosedistribution using positron emission tomography PET technique In this project we useMCNPX 2 6 0 simulations to predict the yield of positron emitters produced by a 250 MeVproton beam in soft tissue and our results in comparision with some previous works withdifferent cross section data resources show fairly good agreement Proton beams with differentenergies have different sharp narrow bragg peak and ranges On the other hand tumor treatmentneeds a spread out bragg peak SOBP to cover tumor volume completely So it is possible tocreat a flat wide bragg peak in result of using a native narrow bragg curve and adding someweighted other ones In this project we produce a spread out bragg peak in 4 cm width using 250MeV proton beam bragg curve and adding eight weighted other bragg curves in different energyand ranges with MCNPX code Key words Proton therapy nuclear interactions positron emitters MCNPX bragg curve

احمد شيراني

محمدحسن علامت ساز

اكبر پروازيان،ظفرا... كلانتري