Sterilization of medical products using TWINDUS LINAC-1: a dosimetric measurements

Dosimetric measurements for sterilization of medical disposable devices have been carried out using indigenously developed 5kW TWINDUS Linac-1. Electron beam sterilization of medical devices is one of the most efficient and safe processes, as it destroy the viable microorganisms without altering the product material. Radiation processing is a complex process, and requires determination of beam characteristics (beam energy, current, penetration, scan uniformity) and its relationship with conveyor speed and absorbed dose, dose mapping to characterize the irradiator with respect to the distribution of dose and variability of dose. In order to qualify the irradiation sterilization process the dosimetric measurement were carried out using Alanine EPR dosimeters and radiochromic films. Electron beam energy was measured using Riso aluminium wedge phantom. Detailed dosimetric measurement were carried-out at 9 MeV. Depth dose profile was measured in husk (density 0.15 g/cc equivalent to medical products) filled box of size 60×34×43cm³ . Beam parameters, scanning parameters and conveyor parameters were optimized to achieve surface dose uniformity better than 3%. Three-dimensional volumetric dose measurements were performed to determine the dose minimum and dose maximum position inside the box filled with Petri plates. The process was optimized to achieve DUR of 1.35. This paper presents the dosimetric measurements carried out for qualification of Linac as radiation source for medical product sterilization. (author)