Target splitting in radiation therapy for lung cancer: further developments and exemplary treatment plans.

BACKGROUND: Reporting further developments evolved since the first report about this conformal technique. METHODS: Technical progress focused on optimization of the quality assurance (QA) program, especially regarding the required work input; and on optimization of beam arrangements. RESULTS: Besides performing the regular QA program, additional time consuming dosimetric measurements and verifications no longer have to be accomplished.'Class solutions' of treatment plans for six patients with non-resected non-small cell lung cancer in locally advanced stages are presented. Target configurations comprise one central and five peripheral tumor sites with different topographic positions to hilus and mediastinum. The mean dose to the primary tumor is 81,9 Gy (range 79,2-90,0 Gy), to macroscopically involved nodes 61,2 Gy (range 55,8-63,0 Gy), to electively treated nodes 45,0 Gy. Treatments are performed twice daily, with fractional doses of 1,8 Gy at an interval of 11 hours. Median overall treatment time is 33 days. The set-up time at the linac does not exceed the average time for any other patient. CONCLUSION: Target splitting is a highly conformal and nonetheless non-expensive method with regard to linac and staff time. It enables secure accelerated high-dose treatments of patients with NSCLC.