Gudowska Irena, Sobolevsky Nikolai
Department of Medical Radiation Physics, Karolinska Institutet and Stockholm University, Box 260, S-171-76 Stockholm, Sweden.
Radiat Prot Dosimetry. 2005;116(1-4 Pt 2):301-6. doi: 10.1093/rpd/nci023.
During radiation therapy with an ion beam, the production of secondary particles like neutrons, protons and heavier ions contribute to the dose delivered to tumour and healthy tissues outside the treated volume. Also, the secondary particles leaving the patient are of interest for radiation background around the ion-therapy facility. Calculations of secondary particle production and the dose absorbed by water, soft tissue and a multi-material phantom simulating the heterogeneous media of the patient body were performed for protons, helium, lithium and carbon ions in the energy range up to 400 MeV u(-1). The Monte Carlo code SHIELD-HIT for transport of protons and light ions in tissue-like media was used in these studies. The neutron ambient dose-equivalent, H*(10), was determined for neutrons leaving the water phantom irradiated with different light ion beams. The comparison of calculated secondary particle production in the water and PMMA phantoms irradiated with helium and carbon ions shows satisfactory agreement with experimental data.
在离子束放射治疗期间，诸如中子、质子和重离子等次级粒子的产生会对传递到肿瘤以及治疗体积之外的健康组织的剂量产生影响。此外，离开患者身体的次级粒子对于离子治疗设施周围的辐射本底而言也是值得关注的。针对能量高达400 MeV u(-1) 的质子、氦离子、锂离子和碳离子，进行了次级粒子产生以及水、软组织和模拟患者身体异质介质的多材料体模所吸收剂量的计算。这些研究中使用了用于在类组织介质中传输质子和轻离子的蒙特卡罗代码SHIELD-HIT。针对用不同轻离子束辐照的水体模所产生的中子，确定了中子周围剂量当量H*(10)。对用氦离子和碳离子辐照的水体模和聚甲基丙烯酸甲酯体模中计算出的次级粒子产生情况进行比较，结果表明与实验数据吻合良好。
