Recent advances in Positron Emission Tomography PET Tony

Recent advances in Positron Emission Tomography (PET) Tony Streng 13. 2. 2020

Introduction Image License: Brudersohn [CC BY-SA (https: //creativecommons. org/licenses/by-sa/3. 0)] Taken from: https: //commons. wikimedia. org/wiki/File: PETCT_Siemens_Biograph 01. jpg Recent advances in Positrion Emission Tomography (PET) 2. 1. 2022 2

Overview 1. Positron - What, why and how? 2. Gamma photon - Emission and properties - Detection and pairing 3. Biomarkers - What is their core - How are they related to pet 4. Tumor detection - Tumor detection with PET using fluorodeoxyglucose 5. Explorer system - Benefits, drawbacks and current progress Recent advances in Positrion Emission Tomography (PET) 2. 1. 2022 3

Positron, what is it and how is it useful? • Positron is the antiparticle of an electron • Creates an annihilation rection with electrons • Annihilation reaction produces two 511 ke. V photons • The photons are antiparallel to each other • Emitted by β+ radioactive decay • Fluorine-18 most commonly radionuclide • Positron ’travels’ before annihilation • In water, average <1 mm but up to 3. 8 mm Image taken from Rösch, Frank. Nuclear-and Radiochemistry. Walter de Gruyter Gmb. H & Company, KG, 2014. Recent advances in Positrion Emission Tomography (PET) 2. 1. 2022 4

Gamma ray photon detection • Photons are detected by scintillator-based detectors • Gamma photon is absorbed by the scintillator material • Then emitted as visible light photon • The photomultiplied photons then detected • Line of reference is made from coinciding events • <10 ns in between • Summed channels Image taken from Lewellen, Tom K. "Recent developments in PET detector technology. " Physics in Medicine & Biology 53. 17 (2008): R 287. Recent advances in Positrion Emission Tomography (PET) 2. 1. 2022 5

Biomarkers in PET-scanning • β+ Radioactive atom • Is substituted to metabolically active biomolecule • A couple examples are: 11 C, 13 N, 15 O and 18 F • Flourodeoxyglucose • 18 F substituted into a glucose analogue • Behaves almost the same as glucose in the body • Created from mannose triflate • Most used biomarker for PET-scans Recent advances in Positrion Emission Tomography (PET) 2. 1. 2022 6

How to create FDG Image taken from Yu, S. "Review of 18 F-FDG synthesis and quality control. " Biomedical imaging and intervention journal 2. 4 (2006). Recent advances in Positrion Emission Tomography (PET) 2. 1. 2022 7

How to detect tumours using PET-scans?

Tumour detection using FDG and PETCT-scan • FDG uptake in malignant tumours high • Malignant tumours light up • Lymph node tumour in neck • PET used to find primary tumour and metastases Recent advances in Positrion Emission Tomography (PET) 2. 1. 2022 9

Any questions so far?

EXPLORER system • Full body system with a lenght of 194 cm • Possible to image whole body at once • Lower doses possible • Faster imaging possible • Dynamic imaging possibility Image taken from https: //explorer. ucdavis. edu/about-explorer Recent advances in Positrion Emission Tomography (PET) 2. 1. 2022 11

Time varying imaging with EXPLORER • Standard biomarker dose of FDG • Imaging time varied Image taken from Badawi, Ramsey D. , et al. "First human imaging studies with the EXPLORER total-body PET scanner. " Journal of Nuclear Medicine 60. 3 (2019): 299 -303 Recent advances in Positrion Emission Tomography (PET) 2. 1. 2022 12

Low dose imaging • 10% of standard dose • Image still of quite good quality Image taken from Badawi, Ramsey D. , et al. "First human imaging studies with the EXPLORER total-body PET scanner. " Journal of Nuclear Medicine 60. 3 (2019): 299 -303 Recent advances in Positrion Emission Tomography (PET) 2. 1. 2022 13

Dynamic imaging • Images taken after injection of standard dose of FDG • Graph shows different activity areas as a function of time Image taken from Badawi, Ramsey D. , et al. "First human imaging studies with the EXPLORER total-body PET scanner. " Journal of Nuclear Medicine 60. 3 (2019): 299 -303 Recent advances in Positrion Emission Tomography (PET) 2. 1. 2022 14

Conclusions • PET images metabolic pathways • Can image different pathways depending on biomarker • EXPLORER system may: • Lower radiation doses • Open up new avenues of diagnosis using PET Recent advances in Positrion Emission Tomography (PET) 2. 1. 2022 15