Research progress on use of tissue equivalent filler in postmastectomy radiation therapy of breast cancer / 中华放射肿瘤学杂志

Although the use of postmastectomy radiation therapy (PMRT) has been proven to bring survival benefit to breast cancer patients, the use of chest wall tissue equivalent filler (bolus) remains controversial. In recent years, a large number of studies have shown that the use of bolus in PMRT does not significantly improve the local control rate, while it can significantly increase the acute skin toxicity, and even leads to more frequent and longer treatment interruption. Existing retrospective studies have indicated that for breast cancer patients undergoing mastectomy and systemic therapy, if there is no skin invasion, it is recommended not to routinely use bolus during radiotherapy. However, higher-level clinical studies are needed for further confirmation.

Research on Individualized Phantom Based on 3D Printing for Radiotherapy Dose Verification / 中国医疗器械杂志

Dose verification is carried out on the individualized three-dimensional phantom based on 3D printing technology, which simulates the anatomical structure of human body, contour shape, tumor anatomical structure and other dangerous organs to the greatest extent, and produces a reasonable and effective dose validation phantom. According to the need to obtain effective patient data, import Mimics software to reconstruct the parts of the body and its surrounding tissues and organs that need to be measured, and make them into three-dimensional shell components. The 3D printing is used to assemble and fill the equivalent tissue, and then the body phantom is made. The phantom was scanned by CT and the data was transmitted to TPS system. The previously completed treatment plan was transplanted to the phantom. The phantom was placed according to the patient's location information, irradiated and measured data. The three-dimensional shell assembly is completely reconstructed according to the patient's data, and the contour difference is not significant. The shell is filled with tissue radiation equivalent material whose CT value is the same as the average CT value of the shell volume. The CT image data show that the radiation equivalence of the phantom is similar to the actual tissue of the patient, and the equivalent dose distribution conforms to the conventional treatment range. It can provide a reliable means of dose verification for the accurate design of intensity modulated radiation therapy.

Dose Effect of Tissue Compensator for 6 MV X-Ray / 대한치료방사선과학회지

It is ideal thing to compensate tissue deficit without skin contamination in curvatured irradiation field of high energy Photon beam. The 3-dimensional compensating technique utilizing tissue equivalent materials to ensure an adequate dose distribution and skin sparing effect was described. This compensator was made of paraffin(70%) and stearin wax (30%) compound. The parameters for evaluation of the effect on skin dose in application of compensator were considered in the size of the field, the thickness of the compensator and the source-to-axis distance. The results are as follows; the skin doses were not changed even though application of the compensator, but depended on the field size and the source-to-axis distance, and the skin doses were only slightly changed within 1% relative errors as increasing the thickness of the compensator in these experiments.