Radiation Oncology/Toxicity/Aorta

Aorta RT Tolerance Pittsburgh; 2008 PMID 18299113 -- "Tolerance of the aorta using intraoperative iodine-125 interstitial brachytherapy in cancer of the lung." (Trombetta MG, Brachytherapy. 2008 Jan-Mar;7(1):50-4.) Retrospective. 278 patients who underwent intrathoracic I-125 brachythearpy. 29 had I-125 impregnated mesh (nomographically guided geometric array) that contacted >50% aorta. Mean prescribed dose 114 Gy (85-120) at 0.5 cm. Mean aortic volume receiving entire prescribed dose 17.2 cm3, mean surface 34.4 cm2. 5/29 received EBRT mediastinal boost. Median F/U 3.7 years Outcome: 1/29 (3%) fatal hemorrhage from suspected great vessel rupture. Brachytherapy was supplemented with 45 Gy EBRT overlapping the implant volume over aorta. No other patients even minor events, no long term sequelae Conclusion: Intrathoracic I-125 safe, may be used even in close proximity to aora. Tolerance of aorta may >120 Gy over lifetime of the implant. Overlapping EBRT should be avoided