Radiological safety assessment for safe transportation of Co-60 disused sealed radioactive sources of teletherapy machines

The radiological circumstances of Co-60 teletherapy source heads were inspected to ensure their safe transportation from four medical college hospitals to CWPSF. In this perspective, shielding containers for four Co-60 source heads were manufactured, and inspected their radiological safety in terms of dose equivalent rates (DERs), as well as Transport Index (TI). In case of DMCH, CMCH, SMAGOMCH and RMCH, maximum DER on container surface were found to be 10.00 µSvh^-1, 13.30 µSvh^-1, 17.16 µSvh^-1, 25.70 µSvh^-1 with observed TI 0.03, 0.05, 0.06, 0.08, respectively. Transport safety was verified by measuring DER on the vehicle surface, as observed in the maximum range of 0.11 - 3.13 µSvh^-1  ; and 0.08 – 0.25 µSvh^-1 at 2 m distance for RMCH, which is significantly less than the IAEA permissible limit [12]. Consequently, DER was further verified at driver’s position, as observed 0.11 – 0.17 µSvh^-1 for head, 0.14- 0.16 µSvh^-1for Chest, 0.11 - 0.13 µSvh^-1 for gonad, and 0.09 – 0.11 for Leg, which are remarkably lesser than the IAEA and ICRP limit of 10 µSvh^-1 and 0.5 µSvh^-1 for occupational and public, respectively. Therefore, the investigated DERs indicated no significant radiological safety concern as per international dose limits [6, 7], and IAEA guidelines for safe transportation of radioactive materials [12].