دز غیرمنتظره و اثر بیولوژیکی ناشی از آلودگی نوترونی در شتاب‌دهنده‌های خطی

نویسندگان

دانشگاه آزاد اسلامی، واحد علوم و تحقیقات تهران، دانشکده فنی و مهندسی، گروه مهندسی پرتوپزشکی

چکیده

فوتون پرانرژی موجب تولید آلودگی نوترونی در شتاب‌دهنده‌های خطی پزشکی می‌شوند. اثر بیولوژیکی نسبی نوترون ۲۰ برابر فوتون است، بنابراین آسیب آن در بافت بیولوژیکی بسیار بیشتر و غیرقابل‌چشم‌پوشی هست. در این پژوهش بررسی دز معادل نوترون در شتاب‌دهنده خطی پزشکی توسط کد مونت‌کارلویی فلوکا انجام‌شده است. نتایج نشان می‌دهد استفاده از میدان‌های درمانی کوچک‌تر، تولید آلودگی نوترونی را در نواحی خارج میدان درمانی افزایش می‌دهد. همچنین نواحی خارج میدان درمانی چندین برابر فوتون، دز نوترونی دریافت می‌کنند. عمده‌ی توزیع دز معادل آلودگی نوترونی در سطح بدن هست که ریسک ایجاد سرطان ثانویه ازجمله سرطان پوست را افزایش می‌دهد.

کلیدواژه‌ها


عنوان مقاله [English]

Unexpected dose and the biological effect of neutron contamination in linear accelerators

نویسندگان [English]

  • Asghar Hadadi
  • Dariush Sardari
  • Elham Saeedzadeh
چکیده [English]

Employing High-energy photons in medical linear accelerators can lead to neutron contamination. The relative biological effect of neutrons is 20 times higher than photons. Consequently, its damage to the biological tissue is much higher and unobtrusive. In this study, we calculated neutron equivalent dose in a medical linear accelerator by the FLUKA Monte Carlo code system. The results show that using smaller treatment fields increases the neutron contamination dose in out-of-field areas. Furthermore, the areas outside the treatment field receive several times higher neutron dose than the photon dose. Most of the neutron dose distribution is at the surface of the human body. So it could increase the secondary cancer risk, including skin cancer.

کلیدواژه‌ها [English]

  • Relative biological effect
  • Neutron contamination
  • Linear accelerator
  • Photoneutron
  • Monte Carlo simulatio
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