Relative Hazards to Radiation Workers in Various Classes o Diagnostic X-ray Procedures,with Special Reference to Ward and Theatre Radiography*

A classification of diagnostic X-ray procedures according to degree of radiation hazard to the radiation worker is presented. It is based on an analysis of published radiation injury cases, on theoretical considerations and on experience in routine radiation protection surveys. The classification is qualitative rather than rigorous and procedures are grouped and ranked according to the following basic protection situations: radiography with all staff excluded from the “radiation area”, radiography with staff in the radiation area, fluoroscopy, and dangerous obsolete techniques. A suggested code of practice for diagnostic X-ray work in wards and operating theatres is appended.     

Value of electrodiagnostic assessment in nonsyndromic microcephaly

PURPOSE: To evaluate the value of electroretinogram (ERG) and visual evoked potentials (VEP) in children with nonsyndromic microcephaly. METHODS: In this observational case series, six children with nonsyndromic microcephaly aged 8.5 to 158 months were examined. Main outcome measures included the amplitude of the flash ERG (photopic, flickering, scotopic, and dark-adapted responses), the amplitude and latency of the VEP (flash or pattern-reversal stimulus), visual acuity, slit-lamp biomicroscopy, and indirect ophthalmoscopy. RESULTS: Three children demonstrated normal fundus appearances, ERG, and VEP responses: two in this group demonstrated poor vision and brain computed tomography in the third showed schizencephaly. The remaining three children demonstrated abnormal ERG with predominant reduction in photopic amplitudes. Retinal pigmentary granularities were detected in two children in this group, one of whom has poor vision, generalized brain atrophy, and 40% reduction in VEP amplitudes. CONCLUSIONS: Abnormal ERG is not uncommon among children with nonsyndromic microcephaly. Although cone photoreceptors are affected more than rods, this does not anticipate poor vision. It appears that defects in posterior visual pathway or developmental malformations of the brain should be responsible for poor visual function in nonsyndromic microcephaly.