Bor nötron yakalama terapisinde oluşan yüksek lineer enerji transferli parçacıkların hücreiçi dozimetrisi
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Dosyalar
Tarih
2017
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Ege Üniversitesi, Fen Bilimleri Enstitüsü
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Bor Nötron Yakalama Terapisi (BNCT), beyin tümörleri, malin melanom ve baş-boyun kanser tedavisinde kullanılabilen iki bileşenli bir radyoterapi tekniğidir. Bu bileşenler, biyokimyasal olarak hedeflenen tümör hücrelerinde biriken 10B izotopu ve düşük enerjili nötronlardır. Düşük enerjili nötronlarla bombardıman edilen tümör hücrelerinde bulunan 10B izotopu, 10B(n,α)7Li reaksiyonuyla yüksek lineer enerji transferli kısa menzilli alfa ve lityum-7 parçacıkları yayarak yüksek dozlar oluşturup tümör hücrelerini tercihli olarak yok etmektedir. Bor Nötron Yakalama Terapisinin avantajı, radyasyon etkisinin sadece tümör hücrelerinde sınırlı kalabilmesidir. Alfa ve lityum-7 parçacıklarının etkinliği, kısa menzillerinden ve yüksek lineer enerji transferlerinden dolayı hücresel boyutlardadır ve stokastiktir. Dolayısıyla, bu parçacıkların hücresel seviyede olasılıksal enerji depozisyonunu incelemek için mikrodozimetri uygun bir tekniktir. Bu çalışmada, BNCT'nde oluşan alfa ve lityum-7 parçacıklarının hücreiçi seviyelerde etki ve davranışlarını değerlendirmek için menzilleri, durdurma güçleri, teorik olarak, MATLAB programıyla ve GAMOS Monte Carlo simülasyon programıyla, doz ve enerji dağılımları ise farklı BNCT ajanları için GAMOS Monte Carlo simülasyon programıyla hesaplanmıştır. Doz ve enerji dağılımlarını hesaplamak için tekli ve çoklu hücre modelleri oluşturulmuştur. Hücrenin kimyasal kompozisyonu için iki farklı bileşik kullanılmıştır. Hücre dört farklı küresel bölgeye ayrılarak, BNCT ajanlarının farklı hücreiçi bölgelerde biriktiği düşünülerek, 10B dağılımının ve geometri faktörünün doz ve enerji değerlerine etkisi incelenmiştir. Ayrıca iki farklı radyasyon simülasyon modeli kullanılarak sonuçlar birbiriyle karşılaştırılmıştır. Alfa ve lityum-7 parçacıklarının hücreiçi davranışları incelenmiştir. İki hücre modeli için de, 10B birikimi hücre merkezine yaklaştıkça, birim 10B(n,α)7Li reaksiyonuyla hücreye verilen doz ve enerji değerleri artmıştır. Ayrıca, çoklu hücre modeli, tekli hücre modeline göre çevre hücrelerin etkisiyle daha fazla doz ve enerjiye maruz kalmıştır. Bunun yanı sıra, doğru sonuçlar elde etmek için simüle edilen sistem, mümkün olduğu kadar gerçekçi modellenmiştir.
Boron Neutron Capture Therapy (BNCT), a binary radiotherapy technique that can be used to treat brain tumors, malign melanoma and head-neck cancer. These components are the 10B isotope that accumulates in biochemically targeted tumor cells and low-energy neutrons. The 10B isotope in tumor cells bombarded by low-energy neutrons releases high linear energy transfered alpha and lithium-7 particles with short range by means of 10B(n,α)7Li reaction to occur high localized dose to preferentially destroy tumor cells. The advantage of the Boron Neutron Capture Therapy is that the radiation effect could be limited only in tumor cells. The effectiveness of alpha and lithium-7 particles is in cellular dimensions due to their short ranges and high linear energy transfers, and is stochastic. Accordingly, microdosimetry is a suitable technique to investigate the stochastic energy deposition of these particles at cellular level. In the present study, ranges and stopping powers of alpha and lithium-7 particles were calculated by using theoretical approach, MATLAB program and GAMOS Monte Carlo simulation program, while dose and energy distributions were calculated for different BNCT agents by using GAMOS Monte Carlo simulation program in order to evaluate the effects and behaviors of alpha and lithium-7 particles induced by BNCT at subcellular level. Single and multi cell models were developed to calculate dose and energy distributions. Two different compounds were used for the chemical composition of the cell. By dividing the cell into four different spherical regions, considering the accumulation of BNCT agents in different intracellular regions, the effect of 10B distribution and geometry factor on dose and energy values was investigated. In addition, two different radiation simulation models were used to compare their results. The intracellular behavior of alpha and lithium-7 particles was investigated. As 10B accumulated closer to the cell center, the total dose and energy imparted by per 10B(n,α)7Li reaction to the cell increased for both cell models. Also, the multi cell model was exposed to more dose and energy than the single cell model due to the influence of the surrounding cells. Besides, the simulated system was modeled as realistic as possible to obtain accurate results.
Boron Neutron Capture Therapy (BNCT), a binary radiotherapy technique that can be used to treat brain tumors, malign melanoma and head-neck cancer. These components are the 10B isotope that accumulates in biochemically targeted tumor cells and low-energy neutrons. The 10B isotope in tumor cells bombarded by low-energy neutrons releases high linear energy transfered alpha and lithium-7 particles with short range by means of 10B(n,α)7Li reaction to occur high localized dose to preferentially destroy tumor cells. The advantage of the Boron Neutron Capture Therapy is that the radiation effect could be limited only in tumor cells. The effectiveness of alpha and lithium-7 particles is in cellular dimensions due to their short ranges and high linear energy transfers, and is stochastic. Accordingly, microdosimetry is a suitable technique to investigate the stochastic energy deposition of these particles at cellular level. In the present study, ranges and stopping powers of alpha and lithium-7 particles were calculated by using theoretical approach, MATLAB program and GAMOS Monte Carlo simulation program, while dose and energy distributions were calculated for different BNCT agents by using GAMOS Monte Carlo simulation program in order to evaluate the effects and behaviors of alpha and lithium-7 particles induced by BNCT at subcellular level. Single and multi cell models were developed to calculate dose and energy distributions. Two different compounds were used for the chemical composition of the cell. By dividing the cell into four different spherical regions, considering the accumulation of BNCT agents in different intracellular regions, the effect of 10B distribution and geometry factor on dose and energy values was investigated. In addition, two different radiation simulation models were used to compare their results. The intracellular behavior of alpha and lithium-7 particles was investigated. As 10B accumulated closer to the cell center, the total dose and energy imparted by per 10B(n,α)7Li reaction to the cell increased for both cell models. Also, the multi cell model was exposed to more dose and energy than the single cell model due to the influence of the surrounding cells. Besides, the simulated system was modeled as realistic as possible to obtain accurate results.
Açıklama
Anahtar Kelimeler
Bor Nötron Yakalama Terapisi, Boron-10, Alfa Parçacıkları, Lityum-7 Parçacıkları, GAMOS, Hücre, Mikrodozimetri, Doz Dağılımı, Boron Neutron Capture Therapy, Boron-10, Alpha Particles, Lithium-7 Particles, Cell, Microdosimetry, Dose Distribution
