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Dose prescription and treatment planning based on FMISO-PET hypoxia
Stockholm University, Faculty of Science, Department of Physics.ORCID iD: 0000-0002-7101-240X
RaySearch Laboratories AB, Stockholm, Sweden.
Stockholm University, Faculty of Science, Department of Physics.
Linköping University, Sweden.ORCID iD: 0000-0001-8171-2541
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2012 (English)In: Acta Oncologica, ISSN 0284-186X, E-ISSN 1651-226X, Vol. 51, no 2, 222-230 p.Article in journal (Refereed) Published
Abstract [en]

Purpose. The study presents the implementation of a novel method for incorporating hypoxia information from PET-CT imaging into treatment planning and estimates the efficiency of various optimization approaches. Its focuses on the feasibility of optimizing treatment plans based on the non-linear conversion of PET hypoxia images into radiosensitivity maps from the uptake properties of the tracers used. Material and methods. PET hypoxia images of seven head-and-neck cancer patients were used to determine optimal dose distributions needed to counteract the radiation resistance associated with tumor hypoxia assuming various scenarios regarding the evolution of the hypoxic compartment during the treatment. A research planning system for advanced studies has been used to optimize IMRT plans based on hypoxia information from patient PET images. These resulting plans were compared in terms of target coverage for the same fulfilled constraints regarding the organs at risk. Results. The results of a planning study indicated the clinical feasibility of the proposed method for treatment planning based on PET hypoxia. Antihypoxic strategies would lead to small improvements in all the patients, but higher effects are expected for the fraction of patients with hypoxic tumors. For these, individualization of the treatment based on hypoxia PET imaging could lead to improved treatment outcome while creating the premises for limiting the irradiation of the surrounding normal tissues. Conclusions. The proposed approach offers the possibility of improved treatment results as it takes into consideration the heterogeneity and the dynamics of the hypoxic regions. It also provides early identification of the clinical cases that might benefit from dose escalation as well as the cases that could benefit from other counter-hypoxic measures.

Place, publisher, year, edition, pages
2012. Vol. 51, no 2, 222-230 p.
National Category
Radiology, Nuclear Medicine and Medical Imaging
URN: urn:nbn:se:su:diva-76341DOI: 10.3109/0284186X.2011.599815ISI: 000299385600010OAI: diva2:526412


Available from: 2012-05-11 Created: 2012-05-10 Last updated: 2015-06-15Bibliographically approved
In thesis
1. Radiobiological end-points for the theoretical evaluation of the effectiveness of carbon ions and photons in treating tumours with dynamic hypoxia
Open this publication in new window or tab >>Radiobiological end-points for the theoretical evaluation of the effectiveness of carbon ions and photons in treating tumours with dynamic hypoxia
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Tumours are characterised by unorganised vasculature, which often results in hypoxic regions. Hypoxia is a common cause for photon radiotherapy (RT) treatment failure, as hypoxic cells require up to 2-3 times higher doses compared to well-oxygenated cells for the same effect in terms of cell kill. The increase in dose that would be required to treat the tumours of cancer patients is limited by the radiation sensitivity of surrounding normal tissues. Using carbon ions instead of photons, the radiation dose can be conformed to the tumour to a much higher degree, resulting in an improved sparing of normal tissues. In addition, carbon ions have a much higher radiobiological effectiveness near the end of their range, which is positioned in the tumour. Also, the radiation modes of action leading to cell death when carbon ions interact with living tissues, are less sensitive to the oxygen status compared with the action modes of photons.

The focus of this thesis lies in the development of models for the computation of the cell surviving fraction and tumour control probability (TCP) in hypoxic tumours after photon and carbon ion RT. The impact of fractionation was evaluated with regard to possible spatial changes in oxygenation, both for stereotactic body RT and for carbon ion RT. The feasibility of a method to determine and deliver the optimal photon dose for achieving a high TCP according to spatial variations in radiation sensitivity was evaluated in a treatment planning study. The radiobiological models were finally used for the theoretical quantification of the gain in using carbon ions instead of photons.

The results show that there are great possibilities to increase the number of positive outcomes of radiation treatment of tumours if the key influential factors are taken into account, such as level and distribution of hypoxia, radiation quality and choice of fractionation schedule.

Place, publisher, year, edition, pages
Stockholm: Department of Physics, Stockholm University, 2014. 50 p.
OER, hypoxia, LOC, RCR, hypofractionation, SBRT, carbon ion, fractionation, TCP, SF, RCE, RBE
National Category
Other Physics Topics
Research subject
Medical Radiation Physics
urn:nbn:se:su:diva-102731 (URN)978-91-7447-835-8 (ISBN)
Public defence
2014-05-27, CCK Lecture Hall, R8:00, Karolinska Sjukhuset, Solna, 13:00 (English)

At the time of the doctoral defence the following papers were unpublished and had a status as follows; Paper 3: Manuscript; Paper 4: Epubl ahead of print; Paper 5: Manuscript

Available from: 2014-05-05 Created: 2014-04-17 Last updated: 2014-05-05Bibliographically approved

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