magistrsko delo
Tomaž Prašnikar (Avtor), Gregor Serša (Recenzent), Nejc Mekiš (Mentor), Jure Mišič (Komentor)

Povzetek

Uvod: Med najpogostejše preiskave, ki jih opravljamo tako v ambulantni kot bolnišnični dejavnosti, štejemo CT preiskave področja trebušnih in medeničnih organov. Glede na pogostost ponavljanja tovrstnih preiskav in množično kontrolo ob naključnih najdbah, bi bilo smotrno poiskati načine zmanjševanja prejete doze ionizirajočega sevanja in količine kontrastnega sredstva. To lahko dosežemo z različnimi tehnikami slikanja pri računalniški tomografiji. Dvo-energijski CT (ang. Dual-Energy CT) nam v nasprotju s konvencionalno CT metodo (ang. Single-energy CT) omogoča boljšo kontrastno ločljivost slik za biološko oceno mehkih tkiv. Namen: Namen je bil ugotoviti ali lahko s pomočjo tehnike DECT slikanja trebušnih organov zmanjšamo dozo sevanja in količino kontrastnega sredstva ter ohranimo diagnostično kakovost slike, primerljivo s SECT metodo slikanja. Metode dela: Raziskavo smo izvedli na CT aparatu Siemens SOMATOM Drive pri 100 pacientih napotenih na CT preiskavo trebušnih in medeničnih organov (50 z DECT metodo in 50 s SECT metodo). Področje trebušnih organov smo s SECT slikali v dveh fazah – nativna in venska, medtem ko smo z DECT zajeli samo vensko fazo (iz te smo pridobili virtualno nekontrastne slike – VNC). Zbirali smo podatke o pacientovih premerih v AP smeri na transverzalnih rezih v višini zgornjega pola leve ledvice. Za vsakega pacienta smo beležili tudi več dozimetričnih parametrov – CTDIvol, DLP in efektivna doza. Meritve objektivne kakovosti slik smo opravljali z merama SNR in CNR. Podatke o kvaliteti slik smo izmerili na transverzalnih rezih nativnih in venskih faz, področja vene porte in parenhima jeter. Rezultati: Razlika v meritvah AP diametrov na CT aparatu Siemens SOMATOM Drive je med SECT in DECT znašala 1,1 cm (4,2 %) in ni pokazala statistično značilne razlike (p=0,300). Meritve CTDIvol vrednosti venskih faz med metodama SECT in DECT so pokazale statistično značilno razliko – 3,1 % (p=0,033). Skupni DLP je bil pri DECT nižji za 46,8 % od SECT in je bil statistično značilno različen (p<0,001). Posledično je bila efektivna doza s tehniko DECT nižja od SECT za 46,8 % in s tem smo ugotovili, da je bila razlika statistično značilno različna (p<0,001). Pri primerjanju kvalitete med slikami pri SECT in DECT nismo našli statistično značilnih razlik. Rezultati le-teh so bile: SNR native - 9,9 %, SNR CE - 5,9 %, CNR jetrni parenhim - 1,9 % in CNR vena porte - 5,3 %. Razprava: Zaradi različnih tehnik slikanja pacientov na CT aparatu Siemens SOMATOM Drive so se rezultati med seboj razlikovali. Statistično značilne razlike v meritvah DLP in efektivne doze pri CT slikanju trebušnih organov smo opazili z uporabo tehnike DECT. Zaključek: Ob ohranitvi kakovosti slike smo z uporabo tehnike Dual-Energy zmanjšali skupni DLP na posameznega pacienta za 46,8 % in s tem tudi povprečno efektivno dozo za 46,8 %. Zaključimo, da je CT slikanje trebušnih in medeničnih organov z metodo DECT manj dozno obremenjujoče kot SECT slikanje in primerljive kvalitete.

Ključne besede

magistrska dela;radiološka tehnologija;računalniška tomografija;trebušni organi;dvo-energijsko CT slikanje;zmanjševanje doze;kakovost slike;

Podatki

Jezik: Slovenski jezik
Leto izida:
Tipologija: 2.09 - Magistrsko delo
Organizacija: UL ZF - Zdravstvena fakulteta
Založnik: [T. Prašnikar]
UDK: 616-07
COBISS: 151160835 Povezava se bo odprla v novem oknu
Št. ogledov: 20
Št. prenosov: 6
Ocena: 0 (0 glasov)
Metapodatki: JSON JSON-RDF JSON-LD TURTLE N-TRIPLES XML RDFA MICRODATA DC-XML DC-RDF RDF

Ostali podatki

Sekundarni jezik: Angleški jezik
Sekundarni naslov: Dual Energy CT of the abdomen: comparison of radiation dose and contrast medium
Sekundarni povzetek: Introduction: Among the most common procedures that are performed in both outpatient and inpatient hospital setting, are CT procedures of the abdomen and pelvis regions. Given the frequency of recurrence and mass control in the event of accidental findings in such procedures, it would be wise to find ways to reduce radiation dose and the amount of contrast medium. This can be achieved with different acquisition techniques on a CT scanner. Contrary to single energy CT (SECT), Dual-Energy CT (DECT) allows for better contrast resolution and therefore superior evaluation between tissues. Purpose: The main purpose was to determine if a radiation dose reduction, contrast medium reduction and good image quality is achiveable with the use of DECT imaging technique of the abdomen, comparable to SECT. Methods: The research was carried out on a Siemens Dual Source CT system SOMATOM Drive. 100 patients were reffered for CT examination of the abdomen (50 with DECT and 50 with SECT). The abdominal area was scanned twice using the SECT method – native and venous phase. With the DECT method we recorded only the venous phase (the virtual non-contrast images were extracted from this phase – VNC). Consequently, we collected data on patient AP diameters on the transversal planes at the level of the upper pole of the left kidney. For each patient we collected multiple dose value measurements such as CTDIvol, DLP and effective dose. Objective image quality measurements were done with SNR and CNR measures. We measured image quality on the transversal planes of the native and venous phases and in the area of the vena portae and liver parenchyma. Results: Measurements of the AP diameters performed on the Siemens SOMATOM Drive CT scanner amounted to 1,1 cm (4,2 %) and did not show statistically significant differences (p=0,300). The research showed statistically significant differences in CTDIvol measurements between DECT and SECT methods – 3,1 % (p=0,033). The whole DLP value was lower by 46,8 % when performed by the DECT method and showed that the difference was statistically significantly different (p<0,001). Consequently the effective dose using the DECT technique was lowered by 46,8 % from the one using SECT and was found to be statistically significantly different (p<0,001). When comparing image quality between DECT and SECT techniques, we did not find any statistically significant differences. The results of these were: SNR native - 9,9 %, SNR CE - 5,9 %, CNR liver parenchyma - 1,9 % and CNR vena portae - 5,3 %. Discussion: Due to different imaging techniques on the Siemens SOMATOM Drive CT scanner the results differ from each other. With the use of DECT technique in CT procedures of the abdomen, we could achieve statistically significant differences in DLP and effective dose. Conclusion: While maintaining image quality we were able to achieve lower whole DLP and effective dose values of 46,8 % with the use of the DECT technique. We concluded that the DECT method is more dose efficient than the SECT method in CT imaging of the abdomen and pelvis and has very comparable image quality.
Sekundarne ključne besede: master's theses;radiologic technology;computed tomography;abdomen;dual-energy CT;dose reduction;image quality;
Vrsta dela (COBISS): Magistrsko delo/naloga
Študijski program: 0
Konec prepovedi (OpenAIRE): 1970-01-01
Komentar na gradivo: Univ. v Ljubljani, Zdravstvena fak., Oddelek za radiološko tehnologijo
Strani: 57 str., [3] str. pril.
ID: 18818931