Riesgos de la radiación en imágenes pediátricas / Radiation risks in pediatric images

The advance of medical imaging technology has led to an increase in the medical radiation exposure, especially derived from computed tomography (CT). Recent studies confirm a small but significant increase of cancer cases induced by CT radiation. Children are markedly more sensitive to radiation than adults and in addition, their life expectancy is longer, so we must use all resources to optimize and reduce the exposure dose using the ALARA concept. CT is an important diagnostic tool in medical practice and its benefits far outweigh the costs of radiation if the indication is properly justified.

El avance tecnológico de las imágenes para evaluación de enfermedades ha llevado a un aumento considerable de la radiación de origen médica, principalmente la proveniente de la tomografía computada (TC). Estudios recientes confirman un pequeño pero significativo incremento de casos de cáncer inducidos por radiación generada por la TC. Siendo los niños reconocidamente más sensibles a la radiación que los adultos y sumado a su mayor expectativa de vida, es que debemos usar todos los recursos para optimizar y reducir la dosis de exposición aplicando el concepto de ALARA. La TC es una herramienta diagnóstica importantísima en la práctica médica, y sus beneficios superan ampliamente los costos de la radiación si su indicación está adecuadamente justificada.

Mdm2 and p53 Expression in Radiation-Induced Sarcomas of the Head and Neck: Comparison with De Novo Sarcomas

BACKGROUND: The pathogenesis of radiation-induced sarcomas (RISs) is not well known. In RIS, TP53 mutations are frequent, but little is known about Mdm2-p53 interaction, which is a recent therapeutic target of sarcomas. METHODS: We studied the immunohistochemical expression of Mdm2 and p53 of 8 RISs. The intervals between radiation therapy and diagnosis of secondary sarcomas ranged from 3 to 17 years. RESULTS: Mdm2 expression was more common in de novo sarcomas than RISs (75% vs 37.5%), and p53 expression was more common in RISs than in de novo cases (75% vs 37.5%). While half of the RISs were Mdm2(-)/p53(+), none of de novo cases showed such combination; while half of de novo sarcomas were Mdm2(+)/p53(-), which are a candidate group of Mdm2 inhibitors, only 1 RIS showed such a combination. Variable immunoprofiles observed in both groups did not correlate with tumor types, except that all of 2 myxofibrosarcomas were Mdm2(+)/p53(+). CONCLUSIONS: In conclusion, we speculated that both radiation-induced and de novo sarcomagenesis are not due to a unique genetic mechanism. Mdm2-expression without p53 overexpression in 1 case of RIS decreases the future possibility of applying Mdm2 inhibitors on a subset of these difficult tumors.