Early non-invasive detection of brain tumor response to radiation using diffusion weighted MRI

patient ranged from 0.5cm to 2.6 cm, with a median of 1.6 cm. This difference was not related to patient’s AP and right-left dimensions. The lateral distances from the anterior midline are: 3.5 ,-0.4; 2.9 ,-0.4; 2.5 ,-0.4; 2.9 ,-2.7;, and 2.7 ,-0.7 cm, at the 1st, 2nd, 3rd, 4th, and 5th intercostal spaces respectively. Although the IM lateral positions varied from patient to patient, they were relatively consistent in respect to the lateral border of sternum, all located maximally less than 1 cm laterally at 2nd, 3rd, 4th, and 5th intercostal spaces, and 0.5 cm medially of the 1st intercostal space. Distances from the most lateral border of AXN and the most medial border of HH were -2.1 ,-1.3, 0.7 ,-0.5, and 2.9 ,-1.5 cm at levels of HH head, coracoid process and lateral end of clavicle respectively (negative value indicates overlapping). AXN frequently overlapped HH anteriorly when the arm was angled more than 90 degree, but did not when the arm is placed 90 degree or less. The gantry angle of the SCV port also effected HH sparing. The larger the angle, the less HH could be spared. DVHs of IMC, AXN, and HH at different conventional beam settings were also analyzed and showed significant variation of node coverage and HH sparing.