## 3 Results
### Regular PLA Samples  
The results of the regular PLA samples that were printed as blank controls are given in Table 3. The density of the printed samples was observed to be very similar to the density of the LW-PLA samples at each flow rate. The mean HU range was obtained between +132.2 HU and \(-\)734 HU, which is also similar to the results obtained with the  
Figure 7: Axial CT images from different regions of body encompassing different tissues and organs with different mean HU values that can be replicated by LW-PLA.  
LW-PLA samples. The STD\({}_{\text{xy}}\) values, however, were observed to be at higher levels for the regular PLA samples. The regular PLA sample printed with an 80% flow rate exhibited an unexpected STD\({}_{\text{xy}}\) value when compared to the findings from the rest of the sample set. This was due to a partial printing artifact observed at the edge of the sample (Figure 8). After drawing an ROI with a smaller diameter for the exclusion of this artifact, it was found that the actual mean HU and STD\({}_{\text{xy}}\) values for this sample are \(-85.5\) HU and \(\pm 17.2\) HU, respectively.  
Table 4 illustrates the mean HU and STD\({}_{\text{xy}}\) findings of all the regular PLA and LW-PLA samples printed at different temperatures and comparable flow rates. The mean HU values of the regular PLA samples are observed between +132.2 HU and \(-734.4\) HU, which is very similar to the range covered by the LW-PLA samples.  
The STD\({}_{\text{xy}}\) values of the regular PLA samples were observed to increase from \(\pm 13.3\) HU to \(\pm 47.3\) HU as the flow rate was reduced from 100% to 20%, while this trend was not observed in the LW-PLA samples. The STD\({}_{\text{xy}}\) values of the regular PLA samples were observed to be higher than the STD\({}_{\text{xy}}\) values of the LW-PLA samples at all temperatures for each flow rate. This difference was observed to reach a maximum between samples printed with a 20% flow rate (Figure 9). Figure 10, in addition, provides a graphical illustration of the mean HU and STDxy for the regular PLA samples across all flow rates.  
Figure 8: Partial printing artifact that was detected at the edge of the regular PLA sample printed with 80% flow rate and the correction of measured HU and STD values by drawing a circular ROI with smaller diameter.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \
\begin{tabular}{c} **Printing** \\ **Temperature** (\({}^{\circ}\)**C** \\ \end{tabular} & **Flow Rate (\%)** & **Mass (g)** &
\begin{tabular}{c} **Density** \\ **(g/cm\({}^{3}\))** \\ \end{tabular} & **Mean HU** & \(\pm\)**STD\({}_{\text{xy}}\)** & \(\pm\)**STD\({}_{\text{z}}\)** \\ \hline \multirow{6}{*}{230} & 100 & 4.30 & 1.21 & 132.2 & 13.3 & 7.2 \\ \cline{2-6}  & 80 & 3.46 & 0.98 & \(-106.6\) & 41.0 & 10.3 \\ \cline{1-1} \cline{2-6}  & 60 & 2.80 & 0.79 & \(-359.8\) & 22.4 & 9.1 \\ \cline{1-1} \cline{2-6}  & 40 & 2.08 & 0.59 & \(-567.6\) & 38.8 & 8.4 \\ \cline{1-1} \cline{2-6}  & 20 & 1.32 & 0.37 & \(-734.0\) & 47.3 & 3.0 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Regular PLA findings of mass, density, mean Hounsfield Unit (HU), standard deviation on axial plane (STD\({}_{\text{xy}}\)), and longitudinal axis (STD\({}_{\text{z}}\)) under different printing temperatures and flow rates.  
Additionally, it includes a subset of LW-PLA samples that have produced mean HU values similar to those of the regular PLA samples.