Measurement of ionising radiation dose absorbed by bones by using a bone-imitating polymer gel dosimeter

• Bone imitating 3D polymer gel dosimeters were elaborated. • Trabecular bone and dense bone imitating dosimeters are discussed. • Type and concentration of hydroxyapatite impact on dosimeter properties. • Gelation of Pluronic F-127 prevents from sedimentation of hydroxyapatite. Three-dimensional radiotherapy dosimetry allows for high-resolution dose distribution measurements using dosimeters imitating various tissues. This work concerns bone-imitating dosimeters. The following are investigated: (i) manufacturing of bone-imitating dosimeters with two types of calcium hydroxyapatite, (ii) dose response characteristics after irradiation with a 6 MV photon beam, and (iii) tissue equivalence. The main findings include the dosimetric compositions with two types of calcium hydroxyapatite. For 18 % of one type of hydroxyapatite, the dosimeter imitates trabecular bone. For much higher concentrations (>40 %, another hydroxyapatite), the dosimeter approaches the properties of dense bone. The dynamic dose response is not greater than 30 Gy, the linear dose range is <20 Gy (computed tomography and nuclear magnetic resonance measurements), and the dose sensitivity is 0.11–0.18 Gy −1 s −1 (nuclear magnetic resonance measurements) for different weight fractions of hydroxyapatites. In summary, a bone-imitating polymer gel dosimeter can be used to measure the radiation dose in radiotherapy.