The oxygen effect and fractionated radiotherapy

2009 ◽  
pp. 215-231
Keyword(s):  
Oxygen Effect ◽  
Fractionated Radiotherapy

scholarly journals Optimization of Dose Fractionation for Radiotherapy of a Solid Tumor with Account of Oxygen Effect and Proliferative Heterogeneity

Mathematics ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 1204
Author(s):  
Maxim Kuznetsov ◽  
Andrey Kolobov
Keyword(s):  
Tumor Cells ◽  
Solid Tumor ◽  
Tissue Damage ◽  
Normal Tissue ◽  
Dose Fractionation ◽  
Oxygen Effect ◽  
Model Parameters ◽  
Time And Space ◽  
Fractionated Radiotherapy ◽  
Normal Tissue Damage

A spatially-distributed continuous mathematical model of solid tumor growth and treatment by fractionated radiotherapy is presented. The model explicitly accounts for three time and space-dependent factors that influence the efficiency of radiotherapy fractionation schemes—tumor cell repopulation, reoxygenation and redistribution of proliferative states. A special algorithm is developed, aimed at finding the fractionation schemes that provide increased tumor cure probability under the constraints of maximum normal tissue damage and maximum fractional dose. The optimization procedure is performed for varied radiosensitivity of tumor cells under the values of model parameters, corresponding to different degrees of tumor malignancy. The resulting optimized schemes consist of two stages. The first stages are aimed to increase the radiosensitivity of the tumor cells, remaining after their end, sparing the caused normal tissue damage. This allows to increase the doses during the second stages and thus take advantage of the obtained increased radiosensitivity. Such method leads to significant expansions in the curative ranges of the values of tumor radiosensitivity parameters. Overall, the results of this study represent the theoretical proof of concept that non-uniform radiotherapy fractionation schemes may be considerably more effective that uniform ones, due to the time and space-dependent effects.

The oxygen effect and fractionated radiotherapy

2009 ◽  
pp. 207-216 ◽  
Author(s):  
Michael Horsman ◽  
Bradly Wouters ◽  
Michael Joiner ◽  
Jens Overgaard
Keyword(s):  
Oxygen Effect ◽  
Fractionated Radiotherapy

In vivo Monitoring of Oxygen Levels in Human Brain Tumor Between Fractionated Radiotherapy Using Oxygen-enhanced MR Imaging

2020 ◽  
Vol 16 (4) ◽  
pp. 427-432
Author(s):  
Junchao Qian ◽  
Xiang Yu ◽  
Bingbing Li ◽  
Zhenle Fei ◽  
Xiang Huang ◽  
...  
Keyword(s):  
Mr Imaging ◽  
Tumor Cells ◽  
Normal Tissue ◽  
Oxygen Level ◽  
Tissue Oxygen ◽  
Human Brain Tumor ◽  
Fractionated Radiotherapy ◽  
Oxygen Levels ◽  
Oxygen Breathing

Background:: It was known that the response of tumor cells to radiation is closely related to tissue oxygen level and fractionated radiotherapy allows reoxygenation of hypoxic tumor cells. Non-invasive mapping of tissue oxygen level may hold great importance in clinic. Objective: The aim of this study is to evaluate the role of oxygen-enhanced MR imaging in the detection of tissue oxygen levels between fractionated radiotherapy. Methods: A cohort of 10 patients with brain metastasis was recruited. Quantitative oxygen enhanced MR imaging was performed prior to, 30 minutes and 22 hours after first fractionated radiotherapy. Results: The ΔR1 (the difference of longitudinal relaxivity between 100% oxygen breathing and air breathing) increased in the ipsilateral tumor site and normal tissue by 242% and 152%, respectively, 30 minutes after first fractionated radiation compared to pre-radiation levels. Significant recovery of ΔR1 in the contralateral normal tissue (p < 0.05) was observed 22 hours compared to 30 minutes after radiation levels. Conclusion: R1-based oxygen-enhanced MR imaging may provide a sensitive endogenous marker for oxygen changes in the brain tissue between fractionated radiotherapy.

Stroke rate after external fractionated radiotherapy for benign meningioma

2021 ◽  
Author(s):  
Dimitri Vanmarcke ◽  
Johan Menten ◽  
Gilles Defraene ◽  
Frank Van Calenbergh ◽  
Steven De Vleeschouwer ◽  
...  
Keyword(s):  
Stroke Rate ◽  
Benign Meningioma ◽  
Fractionated Radiotherapy
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