MULTIPLE FRACTIONATION

different fractionation in whole brain irradiation for multiple brain metastases

background : this study compared the efficacy of two commonly used fractionation schedules for palliative whole brain irradiation in patients with brain metastases, and assessed the association of the radiotherapy therapy oncology group (rtog) recursive partitioning analysis for brain metastases (rpa) to survival with each schedule. methods : patients with multiple (more than three) brain metas...

Optimal fractionation in radiotherapy with multiple normal tissues.

The goal in radiotherapy is to maximize the biological effect (BE) of radiation on the tumour while limiting its toxic effects on healthy anatomies. Treatment is administered over several sessions to give the normal tissue time to recover as it has better damage-repair capabilities than tumour cells. This is termed fractionation. A key problem in radiotherapy involves finding an optimal number ...

Physiology of Multiple Sulfur Isotope Fractionation during Microbial Sulfate Reduction

Microbial sulfate reduction (MSR) utilizes sulfate as an electron acceptor and produces sulfide that is depleted in heavy isotopes of sulfur relative to starting sulfate. The fractionation of S-isotopes is commonly used to trace the biogeochemical cycling of sulfur in nature, but a mechanistic understanding of factors that control the range of isotope fractionation is still lacking. This thesis...

Tumour radiobiology beyond fractionation

Historically it has been shown repeatedly that single high doses of radiation do not allow a therapeutic differential between tumor and critical normal tissues but dose fractionation does. The purpose of conventional dose fractionation is to increase dose to the tumor while preserving normal tissue function. Tumors are generally irradiated with 2Gy dose per fraction delivered daily to a more or...

Plasma Fractionation in Malaysia