Designing of External Body Frame (Trunk Area) Part for Pediatric Phantom from Law Cost Soft Tissue Equivalent Materials

Radiation is valuable for diagnosis and treatment, but excessive exposure can harm human health. To ensure safety, measuring radiation absorbed by human tissue during imaging is critical. Scientists use phantoms models simulating human bodies or organs, for this purpose. Designing X-ray phantoms requires careful material selection. Most commercial phantoms mimic neonates or adults, leaving a gap for pediatric models (ages 1-15 years). This study aimed to fabricate a low-cost pediatric phantom. The methodology involved creating a lung phantom using dark cork tiles (30.4 × 30.4 × 1.0 cm), cut into coronal plates and stacked to mimic lung anatomy (density: 0.33 g/cm³). The body frame, based on a 3-year-old’s dimensions, was constructed using a wood-and-iron skeletal structure shaped with sea mud. After drying, aluminum barriers and gypsum molds were made for the front and back body parts. The cork lungs and skeletal were placed inside the mold, and a soft tissue-equivalent mixture (STEM) (2.8% calcium carbonate, urethane PMC 121/30 Dry) was poured into the cavity. Once dried, the molds were removed, yielding a complete phantom for testing. Density and Hounsfield Units (HU) were evaluated to simulate human tissue properties. Soft tissue-equivalent material’s (STEM) average density was 1.032±0.007 g/cm³, aligning with the reference range (1.04 g/cm³). Lung density measured 0.441 g/cm³, close to the expected 0.33 g/cm³. HU values for soft tissue ranged from -17 to 44, encompassing muscle (10-40) and adipose tissue (-50 to -100). Lung HU values (-600 to -1014) fell within the standard range (-500 to -1000), validating the material’s efficacy. A full X-ray image of the trunk confirmed the phantom’s structural accuracy and absorption efficiency. Traditional phantoms, often based on Computer tomography (CT) slices, struggle to depict skeletal complexities like vertebrae. In contrast, this model clearly visualizes spinal vertebrae and skeletal details, aiding precise dosage calculations. The study demonstrates the successful fabrication of a pediatric phantom using cost-effective materials, with density and HU values closely matching human tissue. This advancement addresses the critical need for pediatric phantoms in radiation research and clinical applications.