Direkt zum Inhalt
  1. Publizieren |
  2. Suche |
  3. Browsen |
  4. Neuzugänge rss |
  5. Open Access |
  6. Rechtsfragen |
  7. EnglishCookie löschen - von nun an wird die Spracheinstellung Ihres Browsers verwendet.

Biological Dose Accumulation in Image-guided Radiotherapy

Niebuhr, Nina Isabelle

[thumbnail of Dissertation_NinaNiebuhr2019.pdf] PDF, Englisch
Download (21MB) | Nutzungsbedingungen

Zitieren von Dokumenten: Bitte verwenden Sie für Zitate nicht die URL in der Adresszeile Ihres Webbrowsers, sondern entweder die angegebene DOI, URN oder die persistente URL, deren langfristige Verfügbarkeit wir garantieren. [mehr ...]

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.

Dokumententyp: Dissertation
Erstgutachter: Seco, Prof. Dr. Joao
Ort der Veröffentlichung: Heidelberg
Tag der Prüfung: 17 Dezember 2019
Erstellungsdatum: 13 Jan. 2020 09:05
Erscheinungsjahr: 2021
Institute/Einrichtungen: Fakultät für Physik und Astronomie > Dekanat der Fakultät für Physik und Astronomie
DDC-Sachgruppe: 500 Naturwissenschaften und Mathematik
530 Physik
610 Medizin
Leitlinien | Häufige Fragen | Kontakt | Impressum |
OA-LogoDINI-Zertifikat 2013Logo der Open-Archives-Initiative