An investigation of the early detection of radiation induced apoptosis by 99mTc-Annexin V and 201Thallium-chloride in a lung cancer cell line

This study aims to investigate the efficacy of in vitro thaliium-201 chloride (tl-201) and in vitro and in vivo tc-99m hynic-coupled annexin v (tav) in the early detection of radiation induced apoptosis,a proxy indicator of radiation therapy (rt) efficacy. in vitro tl-201 and tav accumulation and efflux in non-small cell lung cancer were measured post irradiation at 5 different gamma ray doses. the replication rates (rr) of the cell lines were also measured. the same non-small cell lung cancer line was inoculated into the left femur. in vivo non-invasive tl-201 and tav tracer biodistribution studies were performed. cell rr decrease with increased radiation dose was observed 48 hours after irradiation. apop-totic cell number was found to have increased in response to 9 gy and 12 gy radiation dose. tl-201 accumulation in the 9 gy and 12 gy irradiation groups was found to be higher than the lower irradiation groups. quick tl-201 efflux was observed in the 9 gy and 12 gy irradiated cells. at 48 hours after irradiation with 9 gy and 12 gy,annexin v accumulation was found to be higher than in the control and 3-6 gy groups. in vivo mouse model confirmed the increased tav uptake in implanted tumors for relatively high 9 gy irradiation as compared to non-irradiated controls. tav may prove to be an effective radiotracer for early assessment of radiation therapy efficacy,via apoptosis,in human lung cancers.