Congress:
EuroSafe Imaging 2021
Keywords:
Lung, Radiographers, Radioprotection / Radiation dose, CT, CT-Angiography, Contrast agent-intravenous, Diagnostic procedure, Radiation safety, Dosimetric comparison, Education and training, Embolism / Thrombosis
Authors:
M. Gentile, A. GUIDI, A. Fidanzio, A. Porcelli, L. Senes, L. Bonomo, A. R. Larici, C. Colosimo
DOI:
10.26044/esi2021/ESI-10569
Methods or background
The in-depth analysis of the current protocols used in our hospital has highlighted some critical issues that are indicated in red in Tables 1.A and 1.B.
Data acquisitions were performed on a CATPHAN T600 phantom and on a PMMA phantom simulating a chest.
For the correctness and accuracy of the calculations, the phantom was positioned and centered by means of a level instrument and by means of the luminous centerers installed on the tomograph. The phantom was fixed to the table in order to avoid movements during the scans.
More than 200 series were performed by varying the following parameters (Tab.2): kVp (80, 100, 120); X-ray Tube Current mA (min 60/max 500); Noise Index (20-70); iterative algorithms (ASIR 20-80%).
Measurements were made on two 64layer multidetector scanners (Revolution EVO, GE; Revolution Maxima, GE). The fixed parameters used were the following: helical full; rotation time 0.4 sec.; detector cover 40 mm; thickness 1.25mm; gap 1.25mm; SFOV large body; DFOV 24 cm (CATPHAN 600) – 36 cm (PPMA); automA, smartmA on; rows/columns: 512; pitch factor (mm/rot): 1:531:1 61,25; convolution kernel: standard; reconstruction option: full/plus – IQ enhance plus; Images: 175; center R/L: R0,0; center A/P: A0,0; scanning length (mm): 217,5 (catphan). TAB. 3A-3B.
Dose analysis (CTDI) and noise were performed on the series carried out on the PMMA phantom.
The following values were measured on the series carried out on the Catphan 600 phantom: noise (sd HU), resolution (MTF Cy / cm), contrast (%), dose (mGy), linearity, uniformity (sd HU).
Table 4 shows the report of the series carried out with the different phantoms, in the different CT systems.
Tables 5 and 6 list all the series performed.