Background: The present study aims to investigate and characterize radiation dosimetric phantom that is made from Rhizophora spp. particleboards using SPC/NaOH/IA-PAE adhesive. Materials and Methods: Modification of soy protein concentrate (SPC) bonded Rhizophora spp. particleboard phantoms were carried out using sodium hydroxide (NaOH) with different amount of bio-based cross-linking agent (IA-PAE) with three different categories of particle size. The radiation attenuation parameters were evaluated with photons energies between 16.59 and 25.26 keV derived from X-ray fluorescence. SPC-based plug phantoms were scanned together with the CT density phantom 062M at 80, 120, and 135 kVp, and 250 mAs. Results: The physical and mechanical properties were found to be improved, while the dimensional stability was decreased through the addition of 15 wt% IA-PAE with decreasing particle size. The lowest HVL and MFP, and the highest μ_m with their corresponding values of Z_eƒƒ  (p-values of 0.054, 0.055, 0.060, and 0.075), and the relatively low X² values are the characteristics of samples labeled as A₁₅, B₁₅, C₁₀, and C₁₅. Sample C₁₅ gave the closest values of CT number, ED, and DDPs to water for all tested tube voltages. Conclusion: The results point to the possibility of employing C₁₅ as a promising TEPM.