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

Y. J. Tseng, W. C. Chu, W. Y. Chung, W. Y. Guo, Y. H. Kao, J. Wang, Sung Cheng Huang

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

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

Original languageEnglish
Pages (from-to)495-502
Number of pages8
JournalMagnetic Resonance Imaging
Volume20
Issue number6
DOIs
StatePublished - Jul 2002

Keywords

  • Ferric ion diffusion
  • Gamma knife radiosurgery
  • MRI-Fricke-infused gel dosimetry
  • Radiation dosimetry
  • Stereotactic radiosurgery

Fingerprint

Dive into the research topics of 'The role of dose distribution gradient in the observed ferric ion diffusion time scale in MRI-Fricke-infused gel dosimetry'. Together they form a unique fingerprint.

Cite this