Autor: |
Tinjak, Enis, Beganovic, Adnan, Smajlbegovic, Velda, Julardzija, Fuad, Sehic, Adnan, Prevljak, Sabina, Metlic, Branka, Salkica, Nusret, Topcagic, Muhamed |
Předmět: |
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Zdroj: |
Knowledge: International Journal; 2022, Vol. 54 Issue 4, p603-610, 8p |
Abstrakt: |
Contouring, planning and dose calculation in treatment planning systems (TPS) are based on computed tomography (CT) images. Therefore, it is important to have developed, optimized and adapted scanning protocols for specific anatomic regions and special radiotherapy modalities such as stereotactic radiosurgery (SRS). The aim of this study was to determine influence of tube voltage, field of view size (FOV) and reconstruction kernels on CT numbers and the resulting radiotherapy (RT) dose calculation. This study was performed at Clinic of Oncology, Clinical Center University of Sarajevo. Verification electron density and CT number values was performed using CIRS Thorax 002LFC phantom, while anthropomorphic CIRS 038 phantom for stereotactic end-to-end verification was used for the purpose of dose plan calculation analysis with large bore CT simulator Canon Aquillion LB.The significant correlation between the tube voltage and the measured values of CT numbers is significant for all materials (p < 0.05), except for water (p = 0.310). No significant correlation between FOV and obtained values of CT numbers was found in any of the evaluated tissue equivalent materials. Evaluating the impact of reconstruction kernels on Hounsfield units (HU), significant deviations were found for the FC62, FC68 and FC07 reconstruction kernels. Also, analyzing the influence of reconstruction kernels on the RT dose calculation, the extreme values are associated with Dmin/D in PTV for kernels FC41 and FC68, where deviations from the values obtained using the baseline scanning parameters were -1.3% and -1.9%. For deviation of 1 HU in muscle tissue of CIRS 002LFC, the calculated Dmin/D in PTV of CIRS STEEV phantom will reduce by 0.79%. Similarly, the reduction of D98 and D2 would be 6.8 cGy and 3.03 cGy for 1 HU, respectively. Change of the reconstruction kernels caused differences of 0.4% in Dmin/D calculation in clinical target volume (CTV). CT scanning and reconstruction parameters may affect Hounsfield units, which could have an impact on dose calculations in RT plan. Hence, it is recommended to standardize the scanning protocol used in calibration curve generation for TPS. One should avoid use of different tube voltages and kernels, while according to this study, the change of FOV will have no impact on dose calculations. [ABSTRACT FROM AUTHOR] |
Databáze: |
Complementary Index |
Externí odkaz: |
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