Right Upper Lobe:
This patient was diagnosed with cT1N0 NSCLC in which we implemented SBRT 50Gy in 5 fractions.
Plan to 50Gy
Plan approved with two points of minor deviation from preferred dosimetric goals for a PTV of 28.9cc: max point dose further than 2 cm from the PTV is 29.67Gy or 59.35% of prescription rather than <58%, which is a minor deviation, and the ratio of the 50% isodose volume to the PTV volume is 4.8 which is a minor deviation as it is preferably less than 4.3 to 4.5. These minor deviations were accepted as they resulted from the attempt to minimize chest wall and rib doses given the proximity of the target to these structures, and therefore the dose fall-off within the lung was necessarily less steep. The max point dose to ribs was 44.66Gy, 1.7cc received 32Gy or more, 36.9cc of chest wall exceeded 24Gy, and only 0.62cc of chest wall exceeded 50Gy. The approved plan has less than 16cc receiving 30Gy or more. The total lung volume at 11Gy was 295cc, and the total lung volume at 12Gy was 265cc.
This is a helpful link for SBRT cases: http://amos3.aapm.org/abstracts/pdf/68-19774-234349-85603.pdf