Radiation physics, quality control, and quality assurance of lung cancer brachytherapy with 125I particles / 中国肿瘤临床

ABSTRACT

Objective:To improve the therapeutic gain ratio from 125I seed implants by investigating the QA/QC strategies used in brachytherapy treatment of lung cancer. Methods:A total of 287 lung cancer and pulmonary metastases cases were studied. Among which, 184 are male and 103 are female with a mean age of 61.9 years. The NOA-NSCLC subgroup and pulmonary metastases were targeted on conventional CT positioning. Considering that COA-NSCL subgroup on the tumor target area is difficult to determine with CT, the coincidence circuit SPECT was used to assist in positioning. A dose-volume histogram was constructed to evaluate the quality of the TPS and optimization. Corrections on real-time positioning are necessary when using an image-guided implantation. The C-LC should be aligned with the FFB for CT-guided percutaneous puncture implantation. After implantation, dosimetry verification was con-ducted. Results:The NOA-NSCLC subgroup, comprising the risk organs such as heart, lung, and spinal column, received an average dose of 137, which was significantly lower than that of normal tissue dose tolerance. The NOA-NSCLC subgroup and lung metastases have matched peripheral dosages of 92.1 and 106.2 Gy with local-control efficiency rates of 91.97% (126/137) and 96.0% (48/50), 1-year survival rates of 91.24%and 83.4%(42/50), and 2-year survival rates of 50.36%(69/137) and 52.3%(26/50), respectively. The 35 COA-NSCL subgroup and 65 lung cancer group have local control efficiency rates of 91.43%(32/35) and 92.3%(60/65) and 1-year survival rates of 88.57%(31/35) and 80.30%(53/66), respectively. Conclusion:Proper radiation dosimetry as a QA/QC strategy was found to improve particle-implantation therapy gain and greatly reduce the risks of radiation pneumonia and pulmonary fibrosis.