eprintid: 27620
rev_number: 18
eprint_status: archive
userid: 4902
dir: disk0/00/02/76/20
datestamp: 2020-01-13 09:05:03
lastmod: 2021-01-29 14:26:07
status_changed: 2020-01-13 09:05:03
type: doctoralThesis
metadata_visibility: show
creators_name: Niebuhr, Nina Isabelle
title: Biological Dose Accumulation in Image-guided Radiotherapy
subjects: ddc-500
subjects: ddc-530
subjects: ddc-610
divisions: i-130001
adv_faculty: af-13
abstract: Dose accumulation (DA), the computation of the total delivered 3D dose distribution Da
of a fractionated radiotherapy treatment using daily patient imaging, is getting established
in clinical practice. Although the aim is to estimate the achieved biological outcome of the
treatment, the principles of biological effect estimation are currently not followed consistently
in the process. In this thesis, the biological effect accumulation approach and total
biological dose (bEQD) were derived as a biologically consistent DA workflow. Clinical
relevance of bEQD and its dependence on individual workflow aspects were investigated
in data from three patient cohorts. It was found that Da systematically underestimates
the obtained biological effect, which can be avoided by the use of bEQD. Results showed
that this is strongest for late-responding organs at risk (OAR) with low �=� values in
dose gradient regions around the target that are prone to organ motion. bEQD to Da
deviations occurred locally, in so-called hotspots, showing individual cases of high difference
magnitude but only small statistical impact. Hotspots of bEQD - Da deviation
around 4 Gy in bladder and rectum were found in patients treated for prostate carcinoma.
Hypofractionation increased these deviations strongly up to 8 Gy and also showed clinically
relevant deviations in dose-volume analysis. Dose-response correlation in standard
fractionation showed only little impact on the DA approaches. Workflow uncertainties are
dominated by those from deformable image registration, which are in the same range as
the difference between bEQD and Da. bEQD should be considered in the application of
treatment adaptation, especially to avoid damage to OARs in individual cases.
date: 2021
id_scheme: DOI
id_number: 10.11588/heidok.00027620
ppn_swb: 1745895531
own_urn: urn:nbn:de:bsz:16-heidok-276200
date_accepted: 2019-12-17
advisor: HASH(0x558eaa803e60)
language: eng
bibsort: NIEBUHRNINBIOLOGICAL2021
full_text_status: public
place_of_pub: Heidelberg
citation:   Niebuhr, Nina Isabelle  (2021) Biological Dose Accumulation in Image-guided Radiotherapy.  [Dissertation]     
document_url: https://archiv.ub.uni-heidelberg.de/volltextserver/27620/1/Dissertation_NinaNiebuhr2019.pdf