[en] Necrosis of brain is an uncommon complication of radiation therapy and may mimic recurrent tumor. The authors of this paper compare gadolinium enhanced MR imaging and contrast-enhanced CT in children with radiation necrosis to determine which modality was more sensitive and if there were any features that would aid in differentiating radiation necrosis from recurrent tumor. The authors studied five children (aged 9-15 y) with radiation necrosis proved by autopsy, biopsy, or long-term follow-up. Three patients had received external beam radiation (dose 3,000-5,440 rad) for glioblastoma, medulloblastoma, and CNS leukemia. Two patients had I-125 seeds (estimated dose, 15,000 rad) implanated for local control of recurrent medulloblastoma. Gadolinium-enhanced MR imaging was followed by contrast-enhanced CT within 24 h

[en] The performance, in-system reprogrammability, flexibility, and reduced costs of SRAM-based field-programmable gate arrays (FPGAs) make them very interesting for high-speed, on-orbit data processing, but, because the current generation of radiation-tolerant SRAM-based FPGAs are derived directly from COTS versions of the chips, their memory structures are still susceptible to single-event upsets (SEUs) . While previous papers have described the SEU characteristics and mitigation techniques for the configuration and user memory structures on the Xilinx Virtex family of FPGAs, we will concentrate on the effects of SEUs on 'half-latch' structures within the Virtex architecture, describe techniques for mitigating these effects, and provide new experimental data which illustrate the effectiveness of one of these mitigation techniques under proton radiation.

[en] Thirty-two children with medulloblastoma were evaluated postoperatively with conventional and gadolinium-enhanced MR imaging. Eleven patients had abnormal cranial MR studies; nine of these had recurrent tumor. In six patients recurrent tumor enhanced with Gd, while in the other three patients recurrent tumor did not enhance. The remaining two patients had areas of abnormal Gd enhancement that were caused by radiation-induced breakdown of the blood-brain barrier rather than by recurrent tumor. This study shows that not all recurrent medulloblastoma enhances and that the absence of Gd enhancement does not necessarily indicate the absence of recurrent tumor

[en] Thirty-two children with medulloblastoma were evaluated postoperatively with conventional and gadolinium-enhanced MR imaging. Eleven patients had abnormal cranial MR studies; nine of these had recurrent tumor. In six patients recurrent tumor enhanced with Gd, while in the other three patients recurrent tumor did not enhance. The remaining two patients had areas of abnormal Gd enhancement that were caused by radiation-induced breakdown of the blood-brain barrier rather than by recurrent tumor. This study shows that not all recurrent medulloblastoma enhances and that the absence of Gd enhancement does not necessarily indicate the absence of recurrent tumor