# Advancing Phantom Fabrication: Exploring 3D-Printed Solutions for Abdominal Imaging Research
## 3 Results
Table 4 presents a comparison of CT numbers (measured in Hounsfield units, HUs) across images from a patient, a commercially available phantom, and a 3D-printed phantom. The table aims to evaluate the accuracy of the phantoms in replicating the CT numbers of different tissues--fat, muscle, and bone--found in a patient. \begin{table}
\begin{tabular}{c c c c c c c c} \hline  & \(\mathbf{U}\) & \(\mathbf{I}\) & \(\mathbf{CTDI}\) & \(\mathbf{T}\) & \(\sigma\) & \(D\) & \(\mathbf{C}\) \\  & **(kV)** & **(mA)** & **(mGy)** & **(mm)** & **(HU)** & **(mm  
Figure 4: Dependence of the contrast of the appendix simulation (parameter \(C\) of the fitted curve) on the tube voltage (80, 100, 120, and 135 kV) and the convolutional kernel used in the phantom scan. There is a significant positive correlation between tube voltage and contrast ([PERSON]’s correlation test, \(p=0.014\)). Figure 5: Dependence of the sharpness of the presentation of the appendix simulation (parameter \(\sigma\) of the fitted curve) on the tube voltage (80, 100, 120, and 135 kV) and the convolution kernel used in the phantom scan. There is a significant correlation between anodic voltage and \(\sigma\) ([PERSON]’s correlation test, \(p=0.001\)). The 3D-printed phantom, which used beeswax to simulate fat tissue, showed a close match to the patient's fat tissue, with no statistically significant difference (\(p\) = 0.428). This indicates that beeswax is an effective material for simulating fat tissue in CT imaging. For muscle tissue, the 3D-printed phantom's resin material exhibits a slightly higher HU value compared with the patient's muscle tissue, but this difference remains within one standard deviation, suggesting reasonable accuracy in the simulation. Similarly, for bone tissue, the 3D-printed phantom showed a higher HU value than the patient images, but this value was still within an acceptable range. By contrast, the commercially available phantom demonstrated a notable discrepancy in representing fat tissue, with a difference of more than two standard deviations from the patient's values, indicating a less accurate simulation. However, the commercially available phantom more accurately represented muscle tissue, with HU values closer to the patients. For bone tissue, the difference between the 3D-printed phantom and the commercially available phantom was not statistically significant (\(p\) = 0.063), suggesting that both phantoms provide a similar level of accuracy in bone tissue simulation. \begin{table}
\begin{tabular}{l c c c} \hline \hline
**Evaluated Object** & **Fat Tissue** & **Muscle Tissue** & **Bone** \\  & **(\(\overline{\pi}\)\(\pm\)\(\sigma\))** & **(\(\overline{\pi}\)\(\pm\)\(\sigma\))** & **(\(\overline{\pi}\)\(\pm\)\(\sigma\))** \\ \hline Patient images & \(-113.6\)\(\pm\) 10.4 & 49.72 \(\pm\) 14.7 & 376 \(\pm\) 120.6 \\
3D-printed phantom & \(-115.41\)\(\pm\) 20.29 & 65.61 \(\pm\) 18.06 & 510 \(\pm\) 131.2 \\ Commercially available phantom & \(-74.78\)\(\pm\) 12.83 & 56.34 \(\pm\) 12.6 & 541 \(\pm\) 101.8 \\ \hline \hline \multicolumn{4}{l}{\(p\)-Values of Student’s \(t\)-test} \\ - & Patient vs. 3D-printed phantom & 0.428 & \(<\)0.001 & \(<\)0.001 \\ - & Patient vs. commercially available phantom & \(<\)0.001 & \(<\)0.001 \\ - & 3D-printed vs. commercially available phantom & \(<\)0.001 & \(<\)0.001 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Comparison of the CT numbers, expressed in terms of Hounsfield unit mean values (\(\overline{\pi}\)) and standard deviation (\(\sigma\)) in 100-pixel regions of interest, for the images of the patient: commercially available phantom and 3D-printed phantom. Figure 6: Dependence of the diameter of the appendix simulation display (parameter \(D\) of the fitted curve) on the tube voltage (80, 100, 120, and 135 kV) and the convolution kernel used in the phantom scan. There is no significant correlation between anodic voltage and \(D\) (Pearson correlation test, \(p\) = 0.357).