Positron emission tomography-computed tomography guided radiotheraphy planning in lung cancer

Aims and background: in three dimensional conformal radiotherapy (3dcrt),treatment planning is based on computerized tomography (ct) images.however, the data obtained from ct may not be sufficient in targetdelination. the purpose of this study is to show the differences between theradiotherapy (rt) plans which were done with positron emission tomography(pet) fusion or not. methods: patients with lung cancer between february2009 and january 2012 at our institution were assessed retrospectively. sixtypatients who were treated with 3dcrt, ct simulation images wereregistrated with pet images. for each patient target volumes weredetermined and normal tissues were revised. wilcoxon signed rank test wasused to compare the two groups. results: for gross tumor volume (gtv),clinical target volume (ctv) and planning target volume (ptv); medianvolume values, median mean dose values and median maximum dose valueswere significantly different according to use of pet. about normal tissuedoses; mean lung dose (mld), lung v20, mean and maximum esophagusdose, v50 and v60, mean heart dose and maximum medulla spinalis dosewere analyzed. conclusion: within these parameters there were statisticallysignificant difference except in maximum dose of esophagus and v60. in ourstudy, we observed decreased target volumes and higher dose distrubutionsfor target volumes in pet registrated rt plans. according to these data, it ispossible to say that optimal rt plans can be formed for lung cancer by usingpet registration.