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Feasibility of elemental tissue decomposition using activation PET after proton irradiation of head and neck squamous cell carcinomas

Pouw, J.E.E. (2020) Feasibility of elemental tissue decomposition using activation PET after proton irradiation of head and neck squamous cell carcinomas.

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Abstract:This thesis studies the clinical feasibility of offline activation positron emission tomography (aPET) to determine the relative amount of oxygen in irradiated head and neck squamous cell carcinomas. In aPET, the generated positron emitters after proton beam irradiation, are measured with a PET scanner outside the treatment room. To define the limits for clinical feasibility, a nonlinear least squares estimation method is specified to estimate the initial mean activity concentration for the generated radionuclides 11C, 15O and 13N. Subsequently, experimental data of five irradiated phantoms are analysed for the maximal time delay, minimal dose delivered, minimal target volume irradiated and minimal difference in element composition between the irradiated materials. To obtain a clinical dose 15O:11C-ratio standard deviation of less than 0.1, target volumes of at least 16mL need to be imaged within 6 minutes after irradiation. Within the defined assumptions, the model seems to be able to differentiate tissue mimicking adipose tissue from muscle mimicking tissue. This maximal time delay makes application of offline aPET impossible in clinical treatment delivery of around 10 minutes, especially considered the presence of biological wash-out in living tissue. Upcoming proton therapy techniques, such as in-beam detection and FLASH-irradiation create options for future aPET application.
Item Type:Essay (Master)
Faculty:TNW: Science and Technology
Subject:44 medicine
Programme:Technical Medicine MSc (60033)
Link to this item:https://purl.utwente.nl/essays/80971
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