Contours: body (green). For the prevention of dose calculation artifacts the PTV1 equals the body contour with an internal margin of 2 mm (yellow). To prevent underdosing in the case of patient movement during treatment a second PTV (PTV2) with minor importance equals the body plus an external margin of 10 mm (red). Lung contours (dark blue). Depending on patient and organ size an internal margin has been created into the lungs to prevent underdosing on the ribs due to respiratory motion. Lung sparing constraints thus refer to the lungs minus the individual internal margin of 0.5-1 cm (light blue). Heart (purple).