Imaging and high-dose proton therapy in chordomas and chondrosarcomas of the axial skeleton

Abstract

The primary objective of this thesis is to identify a set of functional, reproducible, MRI parameters that portray early changes occurring within the chordomas and chondrosarcomas during, and respectively 6 months and 1 year following proton therapy. Secondary objectives are to determine imaging parameters that can portray proton therapy-induced changes; which imaging parameters and sequences are most useful in differential diagnosis of chordomas and chondrosarcomas; and optimization of intensity modulated proton therapy. The final objective is to describe clinical and imaging outcomes and identify side effects in the first cohort of chordoma and chondrosarcoma patients treated with proton therapy in the Netherlands. Application of morphological MRI and CT features in combination with functional MRI parameters for diagnosis of primary bone tumors in the axial skeleton is presented in Chapter 2. Chapter 3 addresses the well-known problem of variability and reproducibility of measured ADC values occurring between different institutions and research groups. The clinical experience with robustly optimized intensity modulated proton therapy (IMPT) and treatment related toxicities in the first skull base, mobile spine and sacral chordoma and chondrosarcoma patients treated with proton therapy at HollandPTC, Delft, The Netherlands are presented in Chapters 4 and 5. Chapter 6 addresses insufficiency fractures in sacral chordoma patients treated with high-dose radiotherapy with/without resection, relative to radiation therapy type and irradiation plans. Chapter 7 addresses the prospective study investigating changes of functional MRI and PET-CT parameters occurring during and, 6 months and 1 year following definitive or (neo-)adjuvant high dose proton therapy in sacral chordoma patients.