In vivo dozimetrija u radioterapiji upotrebom poluvodičkih dioda i optički stimuliranih luminiscentnih dozimetara u 60Co fotonskim snopovima

doctoral thesis

• Title (english): In vivo dosimetry for radiotherapy with semiconductor diodes and optically stimulated luminescent dosimeters in 60Co photon beams
• Author: Iva Mrčela
• Mentor: Zvonko Kusić (mentor)
• Committee member: Damir Bosnar (predsjednik povjerenstva)
• Committee member: Zvonko Kusić (član povjerenstva)
• Committee member: Srećko Lončarić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Physics); Zagreb
• Defense date and country: 2012-01-01, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Physics
• Universal decimal classification (UDC): 53 - Physics

Abstract

U ovom radu opisano je ispitivanje svojstava, priprema i primjena poluvodičkih dioda i optički stimuliranih luminiscentnih dozimetara (OSLD) za in vivo dozimetriju u konvencionalnoj vanjskoj radioterapiji. Cilj istraživanja bio je utvrditi primjenljivost novog OSL dozimetrijskog sustava s pasivnim detektorima od aluminijevog oksida dopiranog ugljikom (Al2O3:C) u kliničkim uvjetima. Ispitivanje dozimetrijskih svojstava detektora provedeno je u terapijskom području doza dobivenih 60Co fotonskim snopovima a uključivalo je, između ostalog, određivanje linearnosti odziva na dozu i reproducibilnosti mjerenja, zatim kalibraciju i određivanje korekcijskih faktora za primjenu u nereferentnim uvjetima. Za OSLD-e je dodatno ispitano slabljenje OSL signala s vremenom, stupanj osiromašenja signala u ponovljenim očitanjima i ovisnost odziva o akumuliranoj dozi. Analizirani su rezultati velikog broja kliničkih in-vivo mjerenja ulaznih doza različitih anatomskih lokalizacija i uvjeta zračenja dobivenih s oba dozimetrijska sustava. Pokazalo se da je ispitivani OSL dozimetrijski sustav pogodan za in vivo dozimetriju te su predloženi postupci za pripremu, kalibraciju i optimalni način upotrebe, koji su potrebni pri uvođenju programa in vivo dozimetrije s OSL detektorima u radioterapiji.

Abstract (english)

This thesis describes characterization, basic dosimetric properties investigation and application of semiconductor diodes and optically stimulated luminescence dosimeters (OSLDs) for in vivo dosimetry in conventional external beam radiotherapy. The aim of this reasearch was to test the performance and suitability of the new commercial dosimetry system based on carbon doped aluminum oxide (Al2O3:C) passive OSLDs in clinical conditions. Investigation was performed with 60Co photon beams within the range of typical therapeutic doses. It included determination of detectors response linearity, measurement reproducibility, comparison of calibration methods and determination of correction factors for use in nonreferent conditions. In addition, for OSLDs, specific features such as depletion of OSL signal with multiple readouts, fading and detector response with acumulated dose, were explored. Large number of entrance dose in vivo measurements were performed with both dosimetry system and results were analyzed regarding different anatomical localization, irradiation techniques and other irradiation conditions during the actual treatment of patients. The investigated OSL dosimetry system proves to be convenient for in vivo dosimetry in radiotherapy and this work presents guidelines in their characterization, calibration and optimal way of use, which are important for the implementation of an in vivo dosimetry program in a clinical environment.

• Keywords: detektori zračenja; in vivo dozimetrija; optički stimulirani luminiscentni dozimetri (OSLD); poluvodičke diode; radioterapija; ulazna doza
• Keywords (english): entrance dose; in vivo dosimetry; optically stimulated luminescence dosimeters (OSLD); semiconductor diodes; radiotherapy; patient dose measurements; radiation detectors
• Language: croatian
• URN:NBN: urn:nbn:hr:217:448086
• Study programme: Title: Physics; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje prirodnih znanosti, polje fizika (doktor/doktorica znanosti, područje prirodnih znanosti, polje fizika)
• Type of resource: Text
• Extent: 142 str.
• File origin: Born digital
• Access conditions: Open access
• Created on: 2017-08-23 11:08:50