Development and validation of a novel three-dimensional patient-specific pediatric brain phantom for computed tomography neuroimaging research.

BACKGROUND: Pediatric head computed tomography (CT) is widely used for urgent neuroimaging, but children's higher radiosensitivity makes protocol optimization and quantitative validation essential. Many available phantoms lack patient-specific pediatric anatomy and realistic brain-mimicking attenuation, limiting their relevance for neuro-CT research and benchmarking. OBJECTIVE: To develop and validate a CT-derived, patient-specific pediatric brain phantom that preserves anatomically faithful geometry and reproduces brain-mimicking soft-tissue attenuation with physics-validated energy dependence. MATERIALS AND METHODS: A fully anonymized head CT of a 5-year-old child was segmented in 3-D Slicer, exported to standard tessellation language (STL), and partitioned into hemispheres. A polylactic acid (PLA) master was three-dimensional (D)-printed to fabricate a reinforced silicone mold. A homogeneous brain-mimicking soft-tissue surrogate was produced by modifying an epoxy system with acetone. The assembled phantom was scanned at 80, 100, 120, and 140 kilovolt peak (kVp). Region of interest (ROI)-based CT numbers were measured across both hemispheres. Computational attenuation verification was performed using Particle and Heavy Ion Transport code System (PHITS) Monte Carlo simulations with a mono-energetic transmission method over 15-150 kiloelectronvolt (keV) and compared with PhyX-Photon Shielding and Dosimetry (PhyX-PSD) and National Institute of Standards and Technology XCOM database (NIST/XCOM) reference. RESULTS: The fabricated phantom preserved the main bilateral morphology and retained 96.85% of the original patient-derived brain volume, with volumes of 1,129.15 cm3 and 1,165.89 cm3, respectively. CT-number and CT-derived mass attenuation coefficient values are reported as mean±standard error of the mean (SEM). At the matched tube voltage of 120 kVp, the mean CT number was 44.94±1.38 Hounsfield units (HU) in the phantom and 40.66±4.13 HU in the source pediatric brain parenchyma, corresponding to an absolute difference of 4.28 HU. Across the complete phantom acquisition series, mean CT numbers increased from 18.55±1.14 HU at 80 kVp to 51.04±0.93 HU at 140 kVp. CT-derived mass attenuation coefficients decreased from 0.1664±0.0002 to 0.1445±0.0001 cm2 g-1 over 80-140 kVp. PHITS-derived attenuation coefficients closely matched the theoretical reference, with relative differences within ±5% across the predefined 15-150 keV diagnostic photon-energy range. CONCLUSIONS: This work establishes the feasibility of producing a 3-D patient-specific pediatric brain component with preserved geometry and clinically relevant bulk CT attenuation, providing a methodological basis for subsequent integration of the skull and other structures into a modular complete-head phantom.