The challenges of precision radiotherapy technology to the traditional theory of radiobiology / 中华放射医学与防护杂志

With the development of modern computing technology and medical physics,radiotherapy has made great progress.The theoretical basis of radiobiology seems to lag behind the clinical application of radiotherapy,which hampers the further improvement of treatment efficacy and the optimization of treatment modality.In this paper,some emerging challenges of precision radiotherapy technology to the traditional theory of radiobiology,such as radiosensitivity,dose-response curve and survival curve,linear-quadratic model,4Rs theory,as well as the interaction between cancer and microenvironment,radiation-induced second primary cancers (RISPC),will be discussed.The interplay between precision radiotherapy and traditional radiobiology theories will be addressed with the aim to potentially solve some of the challenging problems.

Research progress on linear quadratic and biological equivalent dose models for high-dose-per- fraction radiotherapy / 中华放射肿瘤学杂志

The linear quadratic (LQ) model and deduced biological equivalent dose (BED) model are widely applied in the radiobiological studies and the mathematic models of radiation oncology in clinical practice. However, the LQ model cannot accurately fit the experimental and clinical data in the high-dose region under the high-dose-per-fraction treatment mode. To resolve this issue, researchers have made modifications to the LQ models since 2008. In the paper, first, the theoretical basis and the application scope of LQ and BED models were introduced and the debate on whether LQ model is applicable to the high-dose-per-fraction radiotherapy was reviewed. Second, five modified models were introduced in two categories and their characteristics were summarized. Finally, current research situation and existing problems of radiotherapy using biological equivalent dose (BED) models were briefly summarized and the development trend of models was predicted.

Application of stereotactic body radiation therapy in early stage non-small-cell lung cancer / 肿瘤研究与临床

Stereotactic body radiation therapy (SBRT) has been increasingly used in the treatment of early-stage non-small-cell lung cancer (NSCLC).Different from conventional radiotherapy,SBRT is characterized by the delivery of high-dose radiation in 1 to 5 fractions with a high degree of precision and steep dose gradients that minimize the dose to normal tissues,and image guidance technology,image fusion technology and respiratory gating system make the therapy more accurate.SBRT delivers higher biological equralent dose (BED) than conventional radiotherapy.The latest small sample data have suggested outcomes for SBRT patients that superior to the success rate of surgery,and the evidence for SBRT over conventional radiotherapy has resulted in a major change in the standard of care for inoperable NSCLC patients.