Clinical implementation of PET/CT imaging in radiotherapy treatment planning

• Κύριος συγγραφέας: Βασιλού, Αικατερίνη
• Άλλοι συγγραφείς: Vasilou, Aikaterini
• Γλώσσα: English
• Έκδοση: 2021
• Θέματα: Radiation treatment planning; PET/CT; Hybrid imaging; Image registration; Head and neck cancer; Radiotherapy; Nuclear medicine; Feasibility test; Image fusion; Σχεδιασμός πλάνου ακτινοθεραπείας; Υβριδική απεικόνιση; Καρκίνος κεφαλής-τραχήλου; Ακτινοθεραπεία; Πυρηνική ιατρική

The advent of hybrid PET/CT scanners, with coregistered functional and anatomical data, has revolutionized the management of cancer treatment and opened new possibilities for target volume delineation in radiation oncology. This thesis examined how PET/CT can be utilized for treatment planning in the General University Hospital of Patras and how the clinical workflow can be simplified and improved. Initially, this was achieved by conducting a literature study, where articles describing PET/CT in cancer treatment were investigated. These included the essential parameters required in image acquisition for radiotherapy purposes, such as consistency of table tops, use of laser lights, patient’s initial positioning, use of appropriate immobilization devices and data transfer. For this RT-oriented PET/CT procedure, certain limitations and pitfalls were also reviewed. In addition, special attention was given to the collaboration between the nuclear medicine and the radiation therapy department on all levels of interaction. The second part of this thesis concerns the clinical implementation, which started with a presentation of misregistered PET and CT image sets of patients on our department, prior to implementing PET/CT setup in treatment position. Then, a CT-to-ED calibration was performed for the PET/CT scanner, using the Gammex 467 phantom, to accurately account for tissue heterogeneities. Afterwards, a phantom dry-run test was carried out, using the NEMA NU2 phantom, to assess the feasibility of the process of PET/CT performed in treatment position and evaluate its potential to proceed with head and neck cancer patients. So, before the enrollment of the first patient, the current clinical head and neck protocol had to be extended, in order to meet the requirements for radiotherapy planning. Lastly, several feasibility studies were performed with a few head and neck cancer patients, to highlight all the practical issues that need be addressed, so that the procedure can be safely introduced into routine clinical practice. Overall, this thesis can serve as a guidance on practical and clinically validated instructions, which can be deemed useful to the staff involved in the PET/CT-guided radiation treatment planning of our department, as well as to other institutions that wish to follow the same steps and perform a similar procedure.