[Contribution of PET in the follow-up of cerebral metastases in non-small cell lung cancer. A clinical case valuation]. / Aportación de la PET en el seguimiento de las metástasis cerebrales del cáncer de pulmón no microcítico. Valoración de un caso clínico.

We report a clinical case of a male 44 years old with lung adenocarcinoma with a single brain metastases treated with surgery and radiotherapy. The different PET studies performed during the evolution of the disease were very useful and crucial, firstly in the detection of radiation necrosis and after that when cerebral metastases recurrent appeared twice. The radiographic technique (Brain MRI) and the histopathology after the surgical removal confirmed the PET results. PET imaging is helpful in selected patients with brain metastases in lung cancer.

Mapping radiation dose distribution on the fractional anisotropy map: applications in the assessment of treatment-induced white matter injury.

We describe a method to map whole brain radiation dose distribution on to diffusion tensor MR (DT-MR) fractional anisotropy (FA) images and illustrate its applications for studying dose-effect relationships and regional susceptibility in two childhood medulloblastoma survivors. To determine the FA changes voxel-by-voxel in white matter, the post-treatment follow-up FA maps were coregistered to baseline pre-treatment FA maps and automatic segmentation for white matter was carried out. DeltaFA maps representing relative FA change in white matter were hence generated for visual inspection and quantitative analysis. The radiation dose distribution, calculated from radiotherapy plan and exported as images, was coregistered to baseline FA images. DT-MR imaging and processing noise was small with root mean square value of 1.49% for mean DeltaFA. We evaluated the mean DeltaFA changes of regions-of-interest according to radiation dose regions to provide an estimate of the dose-response and found increasing reduction in mean DeltaFA with increasing radiation dose up to 45 Gy after which there was a reversal in the mean FA trend and mean FA approached baseline value. We also found more severe mean FA reduction in the frontal lobes compared to the parietal lobes despite the same radiation dose, suggesting regional susceptibility in the frontal lobe, and mean FA increase in the brainstem after radiation in both patients. We conclude that the method described may be useful in estimating dose-effect relationships and studying regional susceptibility of the brain to radiation in medulloblastoma survivors.