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SU‐E‐T‐256: Evaluation of Silver Dressing as Bolus
Author(s) -
Hipp E,
Becker S,
Osterman K
Publication year - 2013
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.4814691
Subject(s) - materials science , bolus (digestion) , dosimetry , nuclear medicine , composite material , biomedical engineering , surgery , medicine
Purpose: Anti‐microbial silver wound dressing may be useful as a bolus material. This study measures the water‐equivalent‐thickness of a silver wound dressing to characterize it for clinical use. This nylon‐mesh dressing, with its permanently plated silver surface (546 mg Ag/100 cm 2 ) may meet the need for bolus with fine variability of thickness and self‐sterilization. Methods: A percent depth dose (PDD) curve was measured in plastic water (CNMC Best Medical) using a parallel plate chamber (PTW N34001) for an 8×8 cm field size, 6 MV beam, 100 cm SSD with a linear accelerator. Measurements were repeated under varying thicknesses (0.5 mm, 1mm, and 2 mm) of silver dressing material, 10 cm × 11 cm (Silverlon™ Antimicrobial silver wound contact dressing WCD‐466). Control measurements were also made in a small water tank. Results: For every layer of dressing added (∼0.5mm) the PDD shifts to the left along the depth axis. A 2 mm offset applied to the position values of the 2 mm (4‐layers) PDD curve causes superposition with the control PDD. This suggests that 2 mm of silver dressing performs similarly to 2 mm of plastic water. This was verified with measurements under clinical setup conditions, 100 cm to the top of the parallel plate chamber, ie. to skin, with bolus placed on top, under 2 mm plastic water (73.40%) and under 2 mm silver dressing (73.41%). Measurements in a water tank for this equivalent depth agree within 1%. Conclusion: The bolus properties of silver‐mesh dressing appear to be water‐equivalent. Silver dressings can be used as bolus and may be particularly beneficial when fine variations are desired or when maintaining an anti‐microbial environment is of particular value.