dc.contributor.author | Engeseth, Grete May | en_US |
dc.date.accessioned | 2014-07-18T07:39:46Z | |
dc.date.available | 2014-07-18T07:39:46Z | |
dc.date.issued | 2014-05-15 | eng |
dc.date.submitted | 2014-05-15 | eng |
dc.identifier.uri | https://hdl.handle.net/1956/8189 | |
dc.description.abstract | Aim: To analyse the dosimetric effects of density changes, calculation curve errors and geometric errors in proton dose distributions. Methods: Single field optimized treatment plans were created on homogenous and heterogeneous water phantoms. Intensity modulated craniospinal treatment plans were created on CT image data sets from 6 pediatric patients. Setup errors were simulated by shifting the isocenter for ±1 to ±5 mm along the x-, z-and y-axis. Calibration curve errors were simulated by increasing or decreasing the relative stopping power by 1% to 5%. Density changes were simulated by introducing bone and air in the beam path. Result: Air and bone resulted in a change in proton range with a factor of +0,94 and – 0,48, respectively. The V95% was >97% for the CTV regardless of any setup-and calibration curve error, though hotspots and cold spots occurred in the brain. A 3% overshoot caused an increased of 47% in the Dmean for the thyroid. Conclusion: Density changes caused severe alterations of the proton range. Error-induced dose disturbances emerged mainly in areas of complex tissue heterogeneities. Following setup-and calibration curve errors, significant dose escalation were observed for organs at risk in close proximity to the target volume. | en_US |
dc.format.extent | 10775150 bytes | eng |
dc.format.mimetype | application/pdf | eng |
dc.language.iso | eng | eng |
dc.publisher | The University of Bergen | eng |
dc.subject | Radiotherapy | eng |
dc.subject | Proton | eng |
dc.subject | Pediatric | eng |
dc.subject | Active scanning technique | eng |
dc.subject | Proton therapy | eng |
dc.subject | Craniospinal irradiation | eng |
dc.subject.mesh | Radiotherapy | eng |
dc.subject.mesh | Pediatrics | eng |
dc.subject.mesh | Craniospinal Irradiation | eng |
dc.title | Uncertainties in proton therapy: Analysis of the effects of density changes, calibration curve errors and setup errors in proton dose distributions. A treatment planning study performed on water phantoms and craniospinal treatment plans | en_US |
dc.type | Master thesis | |
dc.rights.holder | Copyright the author. All rights reserved | |
dc.description.degree | Master i Radiograf/Bioingeniør | |
dc.description.localcode | MAMD-RAB | |
dc.description.localcode | RABD395 | |
dc.subject.nus | 761901 | eng |
fs.subjectcode | RABD395 | |