Učinki napetosti (kV) in produkta anodnega toka in časa na kvantitativno oceno SPECT/CT slike: študija NEMA body fantoma : magistrsko delo

Karić, Elma (avtor), Rep, Sebastijan (mentor), Ležaič, Luka (komentor), Mekiš, Nejc (recenzent)

Uvod: SPECT/CT naprave igrajo ključno vlogo pri diagnostiki, saj združujejo funkcionalno in anatomsko slikanje, kar omogoča natančno kvantifikacijo aktivnosti in vizualizacijo struktur. Pomemben izziv ostaja optimizacija parametrov slikanja, da bi zmanjšali dozo sevanja, ne da bi pri tem ogrozili kakovost slike. Namen: Cilj raziskave je bil oceniti, kako različne vrednosti napetosti (kV) in jakosti toka (mAs) vplivajo na kvantifikacijo ključnih parametrov slike, kot so impulzi, kBq/ml in SUV, ter na kakovost slike, merjeno s kontrastno-šumnim razmerjem (CNR), in na dozo sevanja, izraženo s CTDIvol in DLP. Metode dela: Raziskava je bila izvedena na NEMA-fantomu z uporabo različnih kombinacij parametrov kV in mAs. Kvantitativna analiza je zajemala oceno impulzov, kBq/ml, SUV, CNR in merjenje doze sevanja (CTDIvol in DLP). Za statistično obdelavo podatkov smo uporabili ANOVA-test, s katerim smo analizirali p- in F-vrednosti za kvantitativne parametre. Rezultati: V analizi impulzov, koncentracij radiofarmacevtov (kBq/ml) in SUV, ter kontrastno-šumnih razmerij (CNR) za različne nastavitve kV in mAs so bile razlike minimalne in niso pomembno vplivale na rezultate. Na primer, maksimalne vrednosti impulza za sfero 1 so se gibale od 61,70 do 62,10 (0,60% odstopanja) pri različnih nastavitvah (130 kV/35 mAs, 110 kV/35 mAs, 80 kV/35 mAs). Podobno so se koncentracije radiofarmacevtov gibale med 19,00 in 19,20 kBq/ml (odstopanje do 1%), SUV med 1,21 in 1,22 (odstopanje do 1%) in CNRmax med 1,00 in 1,06 (odstopanje do 6%). P-vrednosti so bile večje od 0,05, kar pomeni, da ni bilo statističnih razlik med skupinami. Analiza vpliva parametrov kV in mAs na CTDIvol in DLP je pokazala močno pozitivno korelacijo (r > 0,9). Na primer, pri nastavitvah 80 kV/35 mAs je bil CTDIvol 0,85 mGy, medtem ko je pri nastavitvah 130 kV/70 mAs znašal 6,62 mGy. To kaže na pomembnost optimizacije parametrov za zmanjšanje izpostavljenosti sevanju ob ohranjanju kakovosti slike. Razprava in zaključek: Rezultati raziskave potrjujejo, da zmanjšanje parametrov kV in mAs omogoča učinkovito zmanjšanje doze sevanja ob ohranjanju ustrezne diagnostične kakovosti slike in kvantitativnega vrednotenja lezij. Primerjava z relevantnimi raziskavami kaže na skladnost ugotovitev, kar poudarja uporabnost optimizacije parametrov v klinični praksi.

• Jezik: Slovenski jezik
• Ključne besede: magistrska dela, radiološka tehnologija, SPECT/CT, kontrastno-šumno razmerje (CNR), standardizirana vrednost privzema (SUV), CTDIvol, DLP
• Vrsta gradiva: Magistrsko delo/naloga
• Tipologija: 2.09 - Magistrsko delo
• Organizacija: ZF - Zdravstvena fakulteta
• Kraj izida: Ljubljana
• Založnik: [E. Karić]
• Leto izida: 2025
• Št. strani: 68 str.
• PID: 20.500.12556/RUL-169600
• UDK: 616-07
• COBISS.SI-ID: 238496515
• Datum objave v RUL: 06.06.2025

Sekundarni jezik

• Jezik: Angleški jezik
• Naslov: Effects of voltage (kV) and product of anode current and time (mAs) on the quantitative assessment of SPECT/CT images: a study of the NEMA body phantom : master thesis

Izvleček

Introduction: SPECT/CT systems play a pivotal role in modern diagnostic imaging, enabling the quantification of metabolic activity and structural analysis of tissues. However, the challenge of reducing radiation dose remains critical, especially for patients requiring repeated imaging procedures. Purpose: The aim of the study was to evaluate how different voltage (kV) and tube current (mAs) settings impact the quantification of Standardized Uptake Value (SUV), image quality parameters such as Contrast-to-Noise Ratio (CNR), and radiation dose indicators – volumetric dose index (CTDIvol) and Dose-Length Product (DLP). Methods: Imaging was performed using a NEMA phantom across various combinations of voltage and tube current. Key parameters, including SUV, CNR, CTDIvol, and DLP, were analyzed. The results were compared to relevant literature to assess the consistency and clinical applicability of the findings. Results: In the analysis of pulses, radioisotope concentrations (kBq/ml), and SUV, as well as contrast-to-noise ratios (CNR) for various kV and mAs settings, the differences were minimal and did not significantly affect the results. For example, the maximum pulse values for sphere 1 ranged from 61.70 to 62.10 (0.60% deviation) across different settings (130 kV/35 mAs, 110 kV/35 mAs, 80 kV/35 mAs). Similarly, the radioisotope concentrations ranged from 19.00 to 19.20 kBq/ml (up to 1% deviation), SUV ranged from 1.21 to 1.22 (up to 1% deviation), and CNRmax ranged from 1.00 to 1.06 (up to 6% deviation). P-values were greater than 0.05, indicating no statistical differences between the groups. The analysis of the impact of kV and mAs parameters on CTDIvol and DLP showed a strong positive correlation (r > 0.9). For example, at 80 kV/35 mAs, CTDIvol was 0.85 mGy, while at 130 kV/70 mAs, it was 6.62 mGy. This highlights the importance of optimizing parameters to reduce radiation exposure while maintaining image quality. Discussion and conclusion: The results support the study’s hypotheses, emphasizing that optimizing CT-parameters by adjusting voltage and tube current is both feasible and beneficial in clinical practice. Comparison with previous studies confirms that reducing radiation dose parameters can maintain image quality, which is crucial for long-term SPECT/CT imaging solutions

• Ključne besede: master's theses, radiologic technology, SPECT/CT, contrast-to-noise ratio (CNR), standardized uptake value (SUV), CTDIvol, DLP