Multiscale Monte Carlo simulations in metal nanoparticle enhanced photon radiotherapy

[С. Милутиновић]

XV, 179 str.

Elektrotehnika i računarstvo - Nuklearna tehnika / Electrical Engineering and Computer Science - Nuclear Engineering

Fotonska radioterapija pospexena metalnim nanoqesticama (MNQ) je per- spektivna tehnika za leqee raka. Radiosenzibilizujui potencijal MNQ je predmet opsenih multidisciplinarnih istraivaa, koja tokom poslede dve decenije tee da iskoriste ihova jedinstvena svojstva. Znaqajan qinilac teku- ih istraivaa su dozimetrijski proraquni zasnovani na Monte Karlo (MK) simulacijama transporta jonizujueg zraqea. Istraivae u okviru disertacije obuhvata razvoj i primenu tri MK metode za dozimetrijske proraqune. Posebna paa posveena je nanodozimetrijskim simulacijama, centralnom aspektu multiveliqinskog dozimetrijskog koncepta. U prvoj MK studiji naglasak je na ispitivau razlika izmeu simulacija sa homogenizovanom i strukturiranom reprezentacijom regije sa uvedenim MNQ kod proraquna faktora poveaa doze u zavisnosti od sastava, veliqine i kon- centracije MNQ. Simulacije uk uquju napredne fiziqke modele transporta elektrona, strogo ograniqene vrednostima podesivih parametara. Druga MK studija proxiruje istraivae na ispitivae uticaja oblika MNQ i lokali- zacije unutar elije na poveae doze i unutarelijsku raspodelu deponovane energije. Multiveliqinska MK metoda razvijena u treoj studiji nadograu- je prethodno razvijene metode, obezbeujui da simulacijom bude obuhvaena qitava oblast od znaqaja za radioterapijski tretman uz deta niji transport zraqea. Disertacija daje doprinos dinamiqnom razvoju fotonske radioterapije po- spexene MNQ, kroz razvijene MK metode koje omoguavaju istraivae obrazaca deponavaa energije u tumoru na razliqitim prostornim skalama i identifiko- vae optimalnih osobina MNQ i primeenih fotonskih po a sa stanovixta poveaa terapeutskog odnosa i povo nog ishoda radioterapije, kao i kroz rezultate dobijene primenom ovih novih metoda.

Metal nanoparticle (MNP) enhanced photon radiotherapy is a promising technique for cancer treatment. For the past two decades, the radiosensitizing potential of MNPs has been the subject of extensive multidisciplinary research, which strives to utilize their unique properties. Dosimetric calculations based on Monte Carlo (MC) simulations of ionizing radiation transport are an important factor in ongoing investigations within this eld. The research in this dissertation includes the development and application of three MC methods for dosimetric calculations. Special attention is devoted to nanodosimetric simulations, which are the central aspect of the multiscale dosimetry concept. In the rst MC study, the emphasis is on examining the dierence between simulations with homogeneous and structured representations of the region loaded with MNPs, within calculations of the dose enhancement factor for various MNP compositions, sizes and concentrations. The simulations include advanced physics models of electron transport, with stringent limits imposed by adjustable parameters. The second MC study extends the investigation to include the eects of MNP shape and their intracellular localization on the enhancement and intracellular distribution of deposited energy. The multiscale MC method developed in the third study builds on the previously developed methods, providing more detailed radiation transport simulations that encompass the entire region of interest in a radiotherapy treatment. The dissertation contributes to the progress of MNP-enhanced photon radiotherapy through the development of MC methods which enable the patterns of energy deposition in the tumor to be investigated at dierent spatial scales, and optimal properties of the MNPs and of the applied photon elds to be identied, with the end purpose of increasing the therapeutic ratio, as well as through the results obtained by applying these new methods

Monte Karlo simulacije, nanodozimetrija, multiveliqinska dozimetrija, GEANT4, GEANT4-DNA, fotonska radioterapija, metalne nanočestice

Monte Carlo simulations, nanodosimetry, multiscale dosimetry, GEANT4, GEANT4-DNA, photon radiotherapy, metal nanoparticle

621.039:615.8(043.3)

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