Vloga računalniške tomografije pri PET/CT preiskavi in tipične doze pacientov pri CT delu PET/CT preiskav V Sloveniji : magistrsko delo

Perić, Jelena (author), Žontar, Dejan (mentor), Mekiš, Nejc (reviewer)

Uvod: Pozitronska emisijska tomografija (PET) običajno zagotovi zelo malo anatomskih podatkov, zaradi česar je posamezna področja težko natančno lokalizirati. Povezava slikanja PET in visoko ločljivostnega anatomskega slikanja (računalniška tomografija) močno pomaga pri lokalizaciji in karakterizaciji bolezni. Čeprav prinaša več pomembnih koristi je treba opozoriti, da je dodajanje računalniške tomografije k PET sistemu privedlo do znatnega povečanja odmerka sevanja, ki ga prejmejo pacienti. Namen: Namen magistrske naloge je bil oceniti tipične doze, ki jih pacienti prejmejo zaradi CT slikanja pri standardnih PET/CT preiskavah (trije protokoli) na nuklearno medicinskih enotah v Sloveniji in ugotoviti, ali obstajajo statistično značilne razlike med njimi. Metode dela: Na treh PET/CT aparatih (na oddelku za nuklearno medicino na Onkološkem inštitutu - OI, na Kliniki za nuklearno medicino v Ljubljani - KNM in na oddelku za nuklearno medicino v Univerzitetnem kliničnem centru v Mariboru – UKC MB) smo analizirali doze (CTDIvol in DLP), ki jih prejmejo pacienti pri slikanjih s tremi različnimi protokoli (protokol 1: PET/CT slikanje telesa od baze lobanje do sredine stegnenice, protokol 2: PET/CT slikanje telesa od vrha glave do sredine stegnenice, protokol 3: PET/CT slikanje celega telesa od vrha glave do vključno prstov na nogah). Skupna velikost vzorca za raziskavo je zajemala 540 pacientov. Iz že opravljenih preiskav smo s pomočjo računalniškega programa »Syngo.via« in arhiva pacientovih podatkov pridobili podatke o telesni teži, višini in obsevanosti pacientov. Rezultati: Pri protokolu 1 je imel najnižjo skupno vrednost DLP OI in sicer 260 mGy*cm, na KNM so imeli za 10% višji DLP (287 mGy*cm), v UKC MB pa 80% višji (470 mGy*cm). Tudi pri protokolu 2 je imel najnižjo skupno vrednost DLP OI (300 mGy*cm) medtem, ko je imel KNM za 23% višjo (371 mGy*cm), UKC MB pa kar za 70% višjo vrednost (520 mGy*cm). Najnižji dozi pri protokolu 3 so bili izpostavljeni pacienti, ki so opravili PET/CT slikanje na KNM in sicer je bila vrednost DLP 569 mGy*cm, v UKC MB je bila vrednost za 29% višja (734 mGy*cm), najvišjo skupno vrednost pa so imeli na OI (766 mGy*cm). Razprava in zaključek: Na podlagi dobljenih rezultatov lahko zaključimo, da obstajajo precejšne razlike med tremi NM enotami v Sloveniji v prispevku CT slikanja k dozi pacientov. S tem se odpirajo možnosti dodatne optimizacije protokolov, pri čemer je potrebno upoštevati tehnološke omejitve.

• Language: Slovenian
• Keywords: magistrska dela, radiološka tehnologija, pozitronska emisijska tomografija, računalniška tomografija, dozni indeks računalniške tomografije, produkt doze in dolžine preiskovalnega polja
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: ZF - Faculty of Health Sciences
• Place of publishing: Ljubljana
• Publisher: [J. Perić]
• Year: 2020
• Number of pages: 63 str., [6] str. pril.
• PID: 20.500.12556/RUL-116931
• UDC: 616-07
• COBISS.SI-ID: 19850499
• Publication date in RUL: 17.06.2020

Secondary language

• Language: English
• Title: The role of computer tomography in PET/CT examination and typical patient doses from CT part of PET/CT examinations in Slovenia : master thesis

Abstract

Introduction: Positron emission tomography (PET) typically provides very little anatomical data, making it difficult to localize regions accurately. Connection between radionuclide and high resolution anatomical imaging (computed tomography – CT) greatly helps with the localization and characterization of the disease. Although CT has several significant benefits, it should be noted that the addition of CT to the PET system has led to a significant increase in the radiation dose. Purpose: The purpose of this research was to evaluate typical doses that patients receive due to CT imaging in standard PET/CT examinations (three protocols) on nuclear medical units in Slovenia and to determine if there were statistically significant differences between them. Methods: We have analysed the patient doses (CTDIvol and DLP) resulting from the CT imaging by three different protocols (protocol 1: PET/CT imaging of the body from the base of the skull to the middle of the femur, protocol 2: PET/CT imaging of the body from the top of the head to the middle of the femur, protocol 3: PET/CT imaging of the whole body) using three different PET/CT machines (at the Department of Nuclear Medicine at the Institute of Oncology - OI, at the Clinic for Nuclear Medicine in Ljubljana – KNM, at the Department of Nuclear Medicine at the University Clinical Center in Maribor – UKC MB). The presented study included 540 patients (weighing between 70 and 90 kg.). With the help of the computer program "Syngo.via" and the patient data archive, we obtained the patients’ weight, height and dose data. Results: The results show the difference in dose between the three NM units in Slovenia when imaging the same body area. For protocol 1, the OI had the lowest average DLP value (260 mGy*cm), KNM had a 10% higher value (287 mGy*cm) and UKC MB 80% higher (470 mGy*cm). Even with protocol 2, OI had the lowest average DLP value (300 mGy*cm), while the KNM had a 23% higher value (371 mGy*cm) and UKC MB 70% higher (520 mGy*cm). Patients who underwent PET/CT imaging at KNM were exposed to the lowest dose in protocol 3 (DLP = 569 mGy*cm), at UKC MB were exposed to 29% higher dose (734 mGy*cm), the highest doses were omitted at OI (766 mGy*cm). Discussion and conclusion: The results show that there are considerable differences in CT contribution to patient doses between the three NM units in Slovenia. This opens the possibility for further optimization of protocols, taking into account technological limitations.

• Keywords: master's theses, radiologic technology, positron emission tomography, computed tomography, computed tomography dose index, dose length product