Mamografi Çekimlerinde Absorbe Doz Hesaplamaları için MCNPX Monte Carlo Kodunun Değerlendirilmesi

Giriş: Bu çalışma; mamografi çekiminde, meme fantomunda absorbe edilen ortalama doz hesaplamaları için MCNPX Monte Carlo kodunun özelliklerini araştırmayı amaçlamıştır. Ayrıca, tüp voltajı ve meme kalınlığının absorbe olan doza etkisi, Monte Carlo yöntemi kullanılarak belirlenmiştir. Gereç ve Yöntem: Bu çalışmada; absorbe edilen ortalama doz değerleri MCNPX (versiyon 2.4.0) Monte Carlo kodu kullanılarak araştırıldı. Modellenmiş simülasyon düzeneğinin doğrulanması, Al zayıflatıcı maddesinin farklı tüp voltajı (26 ila 32 kV arası) için HVL değerlerinin hesaplanmasıyla elde edilmiştir. Elde edilen HVL değerleri, deneysel sonuçlar ve mevcut Monte Carlo sonuçları ile karşılaştırılmıştır ve literatürle uyumlu bulunmuştur. Bu nedenle, doğrulanmış simülasyon düzeneği, %50-%50 glandular-adipose meme fantomunda absorbe edilen ortalama araştırmak için kullanılmıştır.Bulgular: Elde edilen sonuçlar, literatürdeki çalışmalar ile uyumlu olarak bulunmuştur. Sonuçlar, tüp voltajının 26 dan 32 kV'a çıkarılmasının memedeki dozda 4 kat artış sağladığını göstermiştir. Meme kalınlığında 2 cm den 5 cm kadar olan artışta ise memeye 1.6 kat daha yüksek oranda doz verildiği görülmüştür. Absorbe edilen dozun şiddetinin demet kalitesi ve meme kalınlığına bağlı olduğu sonucuna varılabilir. Sonuç: MCNPX kullanarak yapılan bu modelleme, gelecekteki dozimetrik çalışmalarda, mamografik çekimlerde meme dozu araştırmalarına yardımcı olabilir

Assessment of MCNPX Monte Carlo Code for Absorbed Dose Calculations in Mammogarphy Examination

Introduction: This study aimed to investigate capabities of MCNPX monte carlo code for calculations of average absorbed dose in a breast phantom during mammography examination. Also, the effect of tube voltage and breast thickness on absorbed dose was determined by using Monte carlo method. Materials & Methods: In this study, the average absorbed dose values were investigated by using MCNPX (version 2.4.0) Monte Carlo code. Validation of modeled simulation setup has been obtained by calculating the HVL values of Al attenuator material for different tube voltage (26 to 32 kV ). Obtained HVL values were found to be comparable with experimental results and available Monte Carlo results. Thus, validated simulation setup has been used for investigation of average absorbed dose in a %50-%50 grandular-adipose breast phantom. Results: Our calculated results was consistent with the previous studies and our MC model was validated. The results showed that changing tube voltage from 26 to 32 kV leads to about 4 times increase in breast dose. While increasing breast thick ness from 2 to 5 cm results in 1.6 times higer dose to breast. Conclusion: It can concluded that the breast recieved dose depends strongly beam quality and breast thickness. Our modeling using MCNPX can be used future dosimteric studies concering breast dose investigations in mamograpgy examinations

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