1. Comparison of input values of shielding design parameters for medical linac with IAEA Safety Report Series 47 and calculated values of shielding parameters with treatment delivered data from Square Hospitals. Golam Abu Zakaria Professor & Head Gummersbach Hospital, Academic Teaching Hospital of the University of Cologne Germany M. Anwarul Islam Medical Physicist SQUARE Hospitals Ltd Dhaka-Bangladesh Supervised by Presented by

7. Why more shielding required for IMRT ?? 3 - 5 times more for IMRT than 3DCRT Linac head leakage Similar for both modalities Scattered radiation by primary barrier Similar for 3DCRT & IMRT Scattering radiation by patient Similar for DCRT & IMRT. Workload is equal for both modalities for primary shielding thickness calculation Delivered dose to the tumor per fraction Comments Shielding features

11. Cont. Vertical Wall Vertical Wall Roof Floor

18. Calculated IDR for design limit Output dose rate of the machine = 600MU/Min 1 facilities available only for 3DCRT / 2D 2 if all treatments with IMRT IDR<80 IDR<4 IMRT center 2 IDR<194 IDR<10 3DCRT center 1 Occupational Area Public Area Calculated IDR (in µSv/h) for design limit Treatment Modalities

19. Permissible design limit (Output dose rate of the machine is not mentioned here) (Reference: IAEA Safety Series No. 47) 10mSv/y 6 mSv/y IDR<7.5 --- Occupational IDR<10 1mSv/y IDR<20 IDR<7.5 TADR<0.5 TADR2000<0.15 --- Public N/A Bangladesh USA UK IAEA Permisible Design Limit (in µSv/h) Occupancy Area Treatment Modalities

21. Cont. The calculated radiation dose at the near door & control room of SQUARE hospital was found to be 0.2 mSv/year (Data analyzed within the year of 2010 and 2011 in the basis of the total MU delivered within this time and NSRC survey data) Finally, the study reveals that the radiotherapy department in Square hospital is sufficiently radiation protected for radiation workers and public.