Technical note: the relationship between TV position and the effectiveness and comfort of protective spectacles in...

Although interventional radiological procedures can result in significant eye doses to an operator, protective measures are often rejected because screens are found to impede manipulations, and 0.5 mm lead equivalent spectacles are heavy and uncomfortable. With many units the TV monitors are positioned so that the operator needs to turn his head through 80 degrees or more to view the image while screening. The aim of this study was to determine the distribution of the shielding in protective spectacles which will combine maximum dose reduction for different TV positions with minimum weight. Thermoluminescent dosimeters were used to assess the effectiveness of various spectacles in shielding the lens of the eye when a skull phantom was orientated at different angles in a large area beam of X-rays generated at a tube potential typical of diagnostic energies. The beam was tilted upwards at an angle of 20 degrees as though originating from the irradiated volume of a patient. The results showed that if weight was a consideration, and the head was turned away from the image intensifier through an angle greater than 80 degrees, the shielding was most effective when concentrated in the side-panels of the spectacles. The shape of the side-panels, however, was critical to the adequate shielding of this radiation.