{"id":6224,"date":"2026-10-19T09:48:39","date_gmt":"2026-10-19T09:48:39","guid":{"rendered":"https:\/\/phd.hi.is\/doktorsvorn\/doktorsvorn-i-edlisfraedi-maria-marteinsdottir\/"},"modified":"2026-10-19T09:48:39","modified_gmt":"2026-10-19T09:48:39","slug":"doktorsvorn-i-edlisfraedi-maria-marteinsdottir","status":"publish","type":"phd_defence","link":"https:\/\/phd.hi.is\/en\/doktorsvorn\/doktorsvorn-i-edlisfraedi-maria-marteinsdottir\/","title":{"rendered":"Doktorsv\u00f6rn \u00ed e\u00f0lisfr\u00e6\u00f0i – Mar\u00eda Marteinsd\u00f3ttir"},"content":{"rendered":"
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V\u00f6rninni ver\u00f0ur streymt<\/a><\/p>\n

Doktorsefni:<\/strong>\u00a0Mar\u00eda Marteinsd\u00f3ttir<\/p>\n

Heiti ritger\u00f0ar:<\/strong>\u00a0L\u00edffr\u00e6\u00f0ileg \u00f3vissa \u00ed geislame\u00f0fer\u00f0 me\u00f0 r\u00f3teindum (Biological Uncertainties in Proton Radiation Therapy)<\/p>\n

Andm\u00e6lendur:<\/strong> Dr. Ludvig Muren, pr\u00f3fessor vi\u00f0 Heilbrig\u00f0ise\u00f0lisfr\u00e6\u00f0ideild \u00c1r\u00f3sah\u00e1sk\u00f3la<\/p>\n

Dr. Iuliana Toma-Dasu, pr\u00f3fessor vi\u00f0 E\u00f0lisfr\u00e6\u00f0ideild Stokkh\u00f3lmsh\u00e1sk\u00f3la, og yfirma\u00f0ur l\u00e6kningadeildar \u00ed geislae\u00f0lisfr\u00e6\u00f0i vi\u00f0 Stokkh\u00f3lmsh\u00e1sk\u00f3la<\/p>\n

Lei\u00f0beinandi: <\/strong>\u00a0Dr. Harald Paganetti, pr\u00f3fessor vi\u00f0 Harvard Medical School og forst\u00f6\u00f0uma\u00f0ur e\u00f0lisfr\u00e6\u00f0iranns\u00f3kna \u00e1
Geislame\u00f0fer\u00f0ardeild krabbameinsl\u00e6kninga vi\u00f0 Massachusetts General sj\u00fakrah\u00fasi\u00f0 \u00ed Boston<\/p>\n

Umsj\u00f3narkennari:<\/strong> Dr. Snorri \u00deorgeir Ingvarsson, pr\u00f3fessor vi\u00f0 Raunv\u00edsindadeild H\u00e1sk\u00f3la \u00cdslands<\/p>\n

Einnig \u00ed doktorsnefnd: <\/strong>Gar\u00f0ar M\u00fdrdal, forst\u00f6\u00f0uma\u00f0ur geislae\u00f0lisfr\u00e6\u00f0ideildar Landsp\u00edtala<\/p>\n

Doktorsv\u00f6rn st\u00fdrir:<\/strong>\u00a0Dr. Einar \u00d6rn Sveinbj\u00f6rnsson, pr\u00f3fessor og deildarforseti Raunv\u00edsindadeildar H\u00e1sk\u00f3la \u00cdslands<\/p>\n

\u00a0<\/strong>\u00c1grip<\/strong><\/p>\n

Geislame\u00f0fer\u00f0 sta\u00f0bundinna \u00e6xla (external beam radiation therapy – EBRT) er \u00feaulreynd a\u00f0fer\u00f0 vi\u00f0 krabbameinsl\u00e6kningar me\u00f0 \u00fea\u00f0 a\u00f0 markmi\u00f0i a\u00f0 skila h\u00e1um jafndreif\u00f0um geislaskammti inn \u00ed \u00e6xli\u00f0 sj\u00e1lft \u00e1n \u00feess a\u00f0 ska\u00f0a a\u00f0liggjandi l\u00edkamsvef. Vi\u00f0 n\u00fat\u00edma geislame\u00f0fer\u00f0 eru nota\u00f0ar h\u00e1\u00fer\u00f3a\u00f0ar a\u00f0fer\u00f0ir til a\u00f0 draga \u00far aukaverkunum me\u00f0 \u00fev\u00ed a\u00f0 stilla me\u00f0fer\u00f0argeislann \u00feannig a\u00f0 geislaskammturinn falli hratt \u00feegar \u00fat \u00far \u00e6xlinu kemur og inn \u00ed heilbrig\u00f0an vef. Algengast er a\u00f0 nota styrkm\u00f3ta\u00f0a lj\u00f3seindageisla (intensity modulated radiation therapy – IMRT) en annar valkostur er me\u00f0fer\u00f0 me\u00f0 r\u00f3teindabunu (proton beam therapy – PBT) sem veldur minna geisla\u00e1lagi \u00e1 heilbrig\u00f0an vef vegna hagfelldra e\u00f0liseiginleika r\u00f3teinda.<\/p>\n

L\u00e6knav\u00edsindin b\u00faa a\u00f0 \u00e1ratuga reynslu af geislal\u00e6kningum me\u00f0 lj\u00f3seindum sem reynt er a\u00f0 n\u00fdta vi\u00f0 r\u00f3teindame\u00f0fer\u00f0. Hef\u00f0bundnir geislaskammtar lj\u00f3seinda eru haf\u00f0ir til hli\u00f0sj\u00f3nar \u00feegar skipuleggja \u00e1 me\u00f0fer\u00f0 me\u00f0 r\u00f3teindabunu. A\u00f0 jafna\u00f0i er mi\u00f0a\u00f0 vi\u00f0 fast hlutfall l\u00edffr\u00e6\u00f0ilegrar virkni (relative biological effectiveness – RBE) upp \u00e1 1,1 sem gerir r\u00e1\u00f0 fyrir a\u00f0 r\u00f3teindir hafi 10% meiri l\u00edfr\u00e6n \u00e1hrif en lj\u00f3seindir. \u00deessi einfalda n\u00e1lgun gengur hins vegar \u00ed berh\u00f6gg vi\u00f0 ni\u00f0urst\u00f6\u00f0ur fj\u00f6lda ranns\u00f3kna sem s\u00fdna a\u00f0 RBE stu\u00f0ullinn er breytilegur eftir st\u00e6r\u00f0 geislaskammts, e\u00f0li l\u00edkamsvefs, orkuskilum \u00e1 lengdareiningu (linear energy transfer – LET), auk fleiri atri\u00f0a.<\/p>\n

Markmi\u00f0 ritger\u00f0arinnar var a\u00f0 meta kl\u00edn\u00edsk \u00e1hrif sem og l\u00edffr\u00e6\u00f0ilega \u00f3vissu \u00ed r\u00f3teindame\u00f0fer\u00f0 me\u00f0 \u00fev\u00ed a\u00f0 bera fastan RBE stu\u00f0ul upp \u00e1 1,1 saman vi\u00f0 breytilegan RBE stu\u00f0ul. \u00deessu var \u00e1orka\u00f0 me\u00f0 \u00fev\u00ed a\u00f0 greina g\u00f6gn \u00far kl\u00edn\u00edskum ranns\u00f3knum og a\u00f0 beita Monte Carlo t\u00f6lvu\u00fatreikningum.<\/p>\n

Stu\u00f0st var vi\u00f0 fj\u00f6gur \u00fe\u00fd\u00f0i krabbameinssj\u00faklinga og ranns\u00f3kninni skipt \u00ed jafnmarga \u00fe\u00e6tti. \u00cd fyrsta \u00fe\u00e6ttinum voru sko\u00f0u\u00f0 kl\u00ednisk \u00e1hrif \u00feess a\u00f0 nota breytilegan RBE stu\u00f0ul vi\u00f0 me\u00f0fer\u00f0 bl\u00f6\u00f0ruh\u00e1lskrabbameins s\u00f6kum \u00f3vissu \u00ed hlutfalli (\u03b1\/\u03b2)x. Annar \u00fe\u00e1ttur ranns\u00f3knarinnar f\u00f3lst \u00ed mati \u00e1 \u00f3vissu\u00fe\u00e1ttum \u00ed r\u00f3teindame\u00f0fer\u00f0 \u00e1 litlu me\u00f0fer\u00f0arsv\u00e6\u00f0i, sem rekja m\u00e1 til breytilegs RBE stu\u00f0uls vegna h\u00e6kkunar \u00e1 orkuskilun \u00e1 lengdareiningu (LET) innan me\u00f0fer\u00f0arsv\u00e6\u00f0isins. Auk \u00feess var kanna\u00f0 hva\u00f0a \u00e1hrif \u00fea\u00f0 hefur \u00e1 mat \u00e1 RBE stu\u00f0ulinn \u00e1 me\u00f0fer\u00f0arsv\u00e6\u00f0inu me\u00f0 \u00fev\u00ed a\u00f0 draga \u00far umframslaglengd r\u00f3teindageislans en vi\u00f0 kl\u00edn\u00edska r\u00f3teindame\u00f0fer\u00f0 er venja a\u00f0 b\u00e6ta 3,5% + 1 mm vi\u00f0 slaglengdina. \u00deri\u00f0ji \u00fe\u00e1ttur ranns\u00f3knarinnar beindist a\u00f0 sj\u00faklingum sem fengu r\u00f3teindame\u00f0fer\u00f0 me\u00f0 mj\u00f3bunustraumi (pencil beam scanning – PBS) til a\u00f0 me\u00f0h\u00f6ndla \u00e6xli \u00ed vinstra brj\u00f3sti og kl\u00edn\u00edskur \u00e1rangur borinn saman vi\u00f0 me\u00f0h\u00f6ndlun me\u00f0 \u00fer\u00edv\u00ed\u00f0ri hnitmi\u00f0a\u00f0ri lj\u00f3seindageislun (three-dimensional conformal radiotherapy – 3DCRT) og m\u00f3ta\u00f0ri sn\u00fanings lj\u00f3seindageislun (volumetric modulated arc therapy – VMAT). \u00cd fj\u00f3r\u00f0a og loka\u00fe\u00e6tti ranns\u00f3knarinnar voru \u00ferj\u00fa mismunandi RBE l\u00edk\u00f6n notu\u00f0 til a\u00f0 meta \u00e1hrif breytilegs RBE stu\u00f0uls \u00e1 me\u00f0fer\u00f0 sj\u00faklinga me\u00f0 sarkmein \u00ed mj\u00fakvef me\u00f0 r\u00f3teindageislun.<\/p>\n

Um doktorsefni\u00f0<\/strong><\/p>\n

Mar\u00eda Marteinsd\u00f3ttir er f\u00e6dd \u00ed Reykjav\u00edk \u00e1ri\u00f0 1980. H\u00fan lauk B.Sc pr\u00f3fi \u00ed e\u00f0lisfr\u00e6\u00f0i fr\u00e1 H\u00e1sk\u00f3la \u00cdslands \u00e1ri\u00f0 2006. \u00c1ri\u00f0 2009 \u00fatskrifa\u00f0ist h\u00fan me\u00f0 M.Sc. pr\u00f3f \u00ed e\u00f0lisfr\u00e6\u00f0i fr\u00e1 Stokkh\u00f3lmsh\u00e1sk\u00f3la og lauk M.Sc. gr\u00e1\u00f0u \u00ed geislae\u00f0lisfr\u00e6\u00f0i \u00e1 heilbrig\u00f0issvi\u00f0i fr\u00e1 Stokkh\u00f3lmsh\u00e1sk\u00f3la \u00e1ri\u00f0 2012. A\u00f0 n\u00e1mi loknu vann Mar\u00eda sem geislae\u00f0lisfr\u00e6\u00f0ingur vi\u00f0 Karolinska sj\u00fakrah\u00fasi\u00f0 \u00ed Stokkh\u00f3lmi. H\u00fan h\u00f3f doktorsn\u00e1m vi\u00f0 H\u00e1sk\u00f3la \u00cdslands \u00e1ri\u00f0 2015 en stunda\u00f0i ranns\u00f3knir s\u00ednar vi\u00f0 Massachusetts General sj\u00fakrah\u00fasi\u00f0 \u00ed Boston \u00e1 geislame\u00f0fer\u00f0ardeild krabbameinsl\u00e6kninga.<\/p>\n<\/div><\/div>","protected":false},"featured_media":4989,"template":"","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"_phd_date_start":"2021-04-08T14:00:00+00:00","_phd_date_end":"2021-04-08T16:00:00+00:00","_phd_location":"","_phd_admission":"A\u00f0gangur \u00f3keypis","_phd_thesis_title":"L\u00edffr\u00e6\u00f0ileg \u00f3vissa \u00ed geislame\u00f0fer\u00f0 me\u00f0 r\u00f3teindum (Biological Uncertainties in Proton Radiation Therapy)","_phd_source_url":"https:\/\/gamli.hi.is\/vidburdir\/doktorsvorn_i_edlisfraedi_maria_marteinsdottir","_phd_source_node_id":"374231","_phd_source_type":"vidburdir","_phd_member_id":748,"footnotes":""},"phd_school":[101,93],"phd_discipline":[105],"class_list":["post-6224","phd_defence","type-phd_defence","status-publish","has-post-thumbnail","hentry","phd_school-raunvisindadeild","phd_school-verkfraedi-og-natturuvisindasvid","phd_discipline-phd-i-edlisfraedi"],"_links":{"self":[{"href":"https:\/\/phd.hi.is\/en\/wp-json\/wp\/v2\/phd_defence\/6224","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/phd.hi.is\/en\/wp-json\/wp\/v2\/phd_defence"}],"about":[{"href":"https:\/\/phd.hi.is\/en\/wp-json\/wp\/v2\/types\/phd_defence"}],"version-history":[{"count":0,"href":"https:\/\/phd.hi.is\/en\/wp-json\/wp\/v2\/phd_defence\/6224\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/phd.hi.is\/en\/wp-json\/wp\/v2\/media\/4989"}],"wp:attachment":[{"href":"https:\/\/phd.hi.is\/en\/wp-json\/wp\/v2\/media?parent=6224"}],"wp:term":[{"taxonomy":"phd_school","embeddable":true,"href":"https:\/\/phd.hi.is\/en\/wp-json\/wp\/v2\/phd_school?post=6224"},{"taxonomy":"phd_discipline","embeddable":true,"href":"https:\/\/phd.hi.is\/en\/wp-json\/wp\/v2\/phd_discipline?post=6224"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}