@MASTERSTHESIS\{IMM2012-06437,
    author       = "M. L. Jensen",
    title        = "Image Analysis of {FET} {PET} scans performed during Chemo-Radiotherapy of Glioblastoma Multiforme",
    year         = "2012",
    school       = "Technical University of Denmark, {DTU} Informatics, {E-}mail: reception@imm.dtu.dk",
    address      = "Asmussens Alle, Building 305, {DK-}2800 Kgs. Lyngby, Denmark",
    type         = "",
    note         = "{DTU} supervisors: Rasmus Larsen, Professor, rl@imm.dtu.dk, {DTU} Informatics, Knut Conradsen, Professor, kc@imm.dtu.dk, {DTU} Informatics. Censor: Jens Damgaard Andersen, Lektor Emeritus",
    url          = "http://www.imm.dtu.dk/English.aspx",
    abstract     = "Clinical evaluation of response to chemoradiotherapy is an important discipline in cancer treatment. The prognosis for patient diagnosed with primary {GBM} is poor, with a median overall survival of 15 months from time of diagnosis.
This thesis characterize the response to chemoradiotherapy in 16 patients with {GBM} treated with a standard dose of 60 Gy in 2 Gy per fraction and concurrent {TMZ}. The patients underwent routine pre-treatment imaging that included several {MRI} modalities as well as a combined {PET}/{CT} using {FET}. {FET} has shown a high affinity for {GBM} while the sensitivity to inflammatory tissue is low, which give a tumor-to-background contrast that is superior to any other imaging modality. The patients underwent a second within-treatment {FET-}scan approximately after 40 Gy of radiotherapy, which formed the basis of response characterization.
Uncertainties associated with background and TBR95 were assessed and individual response criteria based on extreme value indices were established. The average required change in TBR95 , for the response to be considered statistically significant at a 95\% level of confidence was found to be \&\#8722;24\%.
Several intensity- and shape-related parameters, including {TBR,} tumor volume and solidity were calculated and compared to changes in TBR95 . However, clinical evaluation of the patients are needed in order to draw any conclusion about the predictive power of the parameters.
The spatial change in tumor uptake was quantified by an average distance, which was found to be 3.29±2.22 mm. The tumor moved out of the 95\% isodose in 5 out 16 patients at the time of the in-treatment scan.
12 out of 16 patients were characterized as non-responders and alternative treatment strategies were suggested based on the findings in this thesis."
}