The precise determination of 2D dose distribution at high doses and convenient dose measurement methods are ongoing challenges in the study of beam diagnosis on large-scale scientific devices. The current work offers an impressive solution by integrating PEGDA photonic crystal films with HSB (Hue, Saturation, Brightness) image processing technology. Under irradiation by a proton beam with a low energy of 182.5 keV, the dose dependence of the radiochromic properties of PEGDA films was confirmed in the experiment. Low-energy protons can alter the microstructure of PEGDA films during energy deposition, reducing the characteristic distance and decreasing the diffraction center wavelength. Under irradiation by proton beams with high doses from 1 MGy to 17.6 MGy (on average), the PEGDA films exhibited a significant blue shift in color phase, with a clear linear relationship between wavelength and absorbed dose. This study offers a straightforward and effective real-time dose feedback analysis method compared to traditional radiochromic readout systems. This approach, which is based on visual observation and digital image analysis, could provide a precise assessment of dose distribution through intuitive image interpretation. In summary, this work introduces a direct and effective dosimeter along with a simple and rapid method for dose readout, offering valuable validation for beam diagnosis.
Yi Hou,Ying Song,Xiaodong Sun,Yulin Jiang,Meiling He,Yubao Li,Xianchun Chen,Li Zhang
Radiotherapy is a commonly used method for curing cancers that appear on or just below the skin. Because of the dose build-up effect of X-rays, boluses made of various materials such as silica and wax are clinically applied on patients to increase the skin dose for an enhanced therapeutic effect. However, these commercial boluses can’t conform well to the skin’s surface with some curvature, resulting in radiation dose attenuation/loss at the lesion location. To address this limitation, we have developed a nano-titanium dioxide (nTiO2)-incorporated polyurethane/polyacrylamide (TPU/PAAm) hydrogel with multi-functions for fabricating a desirable bolus. The obtained hydrogel exhibits excellent mechanical, adhesive and self-healing properties and can fit closely to the surface of patients with any 3D curvature, eliminating the air gap which is a common problem for commercial boluses applied on patients. In particular, it is encouraging that when using the bolus made of TPU/PAAm hydrogel, the dose distribution including dose coverage, conformability and homogeneity within the planning target volume (PTV) is far superior to that when using the commercial bolus. A sufficient dose shifts toward the surface of the head model and is located only in the lesion site, demonstrating that TPU–PAAm hydrogel can provide an optimal dose distribution and be clinically effective for treating superficial tumors. Furthermore, nTiO2 particles feature uniform dispersion at the nanometer level in hydrogel after being modified by 2,2-bis(hydroxymethyl)propionic acid (DMPA) based on coordination chemistry, endowing the hydrogel with long-acting antibacterial ability. The good cell affinity of TPU–PAAm hydrogel is also confirmed in this study, further ensuring that the TPU–PAAm hydrogel prepared here is a desirable candidate as a tissue equivalent with the advantages of convenient use and effectiveness in radiotherapy.
Tao Yang,Junhui Wang,Jiali Tu,Xiaoxi Zhou,Jiamin Sun,Jian Chen,Wanxin Wen,Yanfei Wang
Cancer prevention and treatment are currently the focus of most research. Dose verification is an important step for reducing the improper dose deposition during radiotherapy. To mend the traditional gel dosimeters for 3D dose verification, a novel rare-earth nanoparticle-based composite gel was prepared, which has good radioluminescence property and reusability. It is a promising phantom material for the new 3D gel dosimeter. TEM, DLS, FT-IR, TGA, and spectrofluorometer were used to determine the chemical structure, micromorphology, and optical performance. Compared to the traditional gel dosimeters, the composite gel has a good linear relationship between the light intensity excited by X-ray and the tube current. Furthermore, it may measure the dose distribution immediately in situ , which reduces errors and saves time. This work provides a new idea for the research of 3D gel dosimeters and promotes the safe and effective use of radiotherapy.
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