The role of dose distribution gradient in the observed ferric ion diffusion time scale in MRI-Fricke-infused gel dosimetry

摘要: Abstract Ferric ion diffusion is a detrimental factor in MRI-Fricke-infused gel dosimetry. In this study, novel approach involving MR image subtraction and fast image-based dosimetry technique to study ferric effects presented. The allows studying dose profile degradation within minutes post-irradiation. relationship between the rate of deterioration distribution gradients can be elucidated with improved imaging temporal resolution also. Our results showed that for gradient 4 Gy/mm or higher, causes apparent 0.5–1 h For gradual change 2.1 smaller, appears insignificant two-hour elapsed time. These observations agree well theoretical analysis square dependence gradient. Because all stereotactic radiosurgery procedures produce steep distributions because ideal “snapshot” scanning cannot achieved, knowledge time scale important experimental designs order avoid potential measurement errors MRI-Fricke-agarose