Faculty, Staff and Student Publications
Publication Date
7-1-2024
Journal
Medical Physics
DOI
10.1002/mp.17056
PMID
38598230
PMCID
PMC11233228
PubMedCentral® Posted Date
7-1-2025
PubMedCentral® Full Text Version
Author MSS
Abstract
Purpose: As carbon ion radiotherapy increases in use, there are limited phantom materials for heterogeneous or anthropomorphic phantom measurements. This work characterized the radiological clinical equivalence of several phantom materials in a therapeutic carbon ion beam.
Methods: Eight materials were tested for radiological material-equivalence in a carbon ion beam. The materials were computed tomography (CT)-scanned to obtain Hounsfield unit (HU) values, then irradiated in a monoenergetic carbon ion beam to determine relative linear stopping power (RLSP). The corresponding HU and RLSP for each phantom material were compared to clinical carbon ion calibration curves. For absorbed dose comparison, ion chamber measurements were made in the center of a carbon ion spread-out Bragg peak (SOBP) in water and in the phantom material, evaluating whether the material perturbed the absorbed dose measurement beyond what was predicted by the HU-RLSP relationship.
Results: Polyethylene, solid water (Gammex and Sun Nuclear), Blue Water (Standard Imaging), and Techtron HPV had measured RLSP values that agreed within ±4.2% of RLSP values predicted by the clinical calibration curve. Measured RLSP for acrylic was 7.2% different from predicted. The agreement for balsa wood and cork varied between samples. Ion chamber measurements in the phantom materials were within 0.1% of ion chamber measurements in water for most materials (solid water, Blue Water, polyethylene, and acrylic), and within 1.9% for the rest of the materials (balsa wood, cork, and Techtron HPV).
Conclusions: Several phantom materials (Blue Water, polyethylene, solid water [Gammex and Sun Nuclear], and Techtron HPV) are suitable for heterogeneous phantom measurements for carbon ion therapy. Low density materials should be carefully characterized due to inconsistencies between samples.
Keywords
Phantoms, Imaging, Heavy Ion Radiotherapy, Calibration, Tomography, X-Ray Computed, Humans, audits, carbon therapy, quality assurance, range, relative stopping power
Published Open-Access
yes
Recommended Citation
Taylor, Paige A; Mirandola, Alfredo; Ciocca, Mario; et al., "Technical Note: Radiological Clinical Equivalence for Phantom Materials in Carbon Ion Therapy" (2024). Faculty, Staff and Student Publications. 4496.
https://digitalcommons.library.tmc.edu/uthgsbs_docs/4496
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