O54. Occupational radiation dose mapping in the hybrid interventional theatre environment evaluated at six Netcare Hospitals

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Introduction The International Commission on Radiological Protection (ICRP) limits the whole body occupational exposure to < 100 mSv over five years and < 50 mSv in any single year. High occupational doses, which can exceed ICRP limits, have become a great concern in hybrid theatres due to the growing complexity of procedures and fluoroscopic time. Adherence to the As Low As Reasonably Achievable (ALARA) principle imposes that distance and shielding should be considered to avoid high staff doses. The aim of this study is to determine the high and low occupational exposure areas present in the hybrid theatres installed at Netcare Hospitals. Materials and methods Six Siemens Artis Zeego Hybrid Labs were used and 1 m2 blocks were placed in a grid pattern on the floor using masking tape. Simulation of a patient in the supine position was achieved using a PTW Normi 4 Flu Phantom. Three imaging protocols were selected for evaluation namely FL15fps, FL+30fps and LV15fps. Dose rate ( μ Gy/h) was measured inside each block at a height of 1.5 m from the floor using a RaySafe Unfors Survey Detector at three common gantry angles and the average was calculated. Results The initial results indicate that the left lateral side is the high exposure area, whereas the left posterior oblique (LPO) side is the lowest. An architectural drawing of a lab is used to illustrate results and the highest exposure for each protocol was recorded to be 257, 925 and 426 μ Gy/h, respectively. The lowest exposure area was recorded to be < 50 μ Gy/h for the outermost LPO corner. Conclusion The result is a relative approximation of high and low dose areas inside the hybrid theatres. Only scatter resulting from common projections were measured as it was not possible to measure all gantry angles. Awareness of high and low exposure areas will lead to a safer environment for radiation workers. The International Commission on Radiological Protection (ICRP) limits the whole body occupational exposure to < 100 mSv over five years and < 50 mSv in any single year. High occupational doses, which can exceed ICRP limits, have become a great concern in hybrid theatres due to the growing complexity of procedures and fluoroscopic time. Adherence to the As Low As Reasonably Achievable (ALARA) principle imposes that distance and shielding should be considered to avoid high staff doses. The aim of this study is to determine the high and low occupational exposure areas present in the hybrid theatres installed at Netcare Hospitals. Six Siemens Artis Zeego Hybrid Labs were used and 1 m2 blocks were placed in a grid pattern on the floor using masking tape. Simulation of a patient in the supine position was achieved using a PTW Normi 4 Flu Phantom. Three imaging protocols were selected for evaluation namely FL15fps, FL+30fps and LV15fps. Dose rate ( μ Gy/h) was measured inside each block at a height of 1.5 m from the floor using a RaySafe Unfors Survey Detector at three common gantry angles and the average was calculated. The initial results indicate that the left lateral side is the high exposure area, whereas the left posterior oblique (LPO) side is the lowest. An architectural drawing of a lab is used to illustrate results and the highest exposure for each protocol was recorded to be 257, 925 and 426 μ Gy/h, respectively. The lowest exposure area was recorded to be < 50 μ Gy/h for the outermost LPO corner. The result is a relative approximation of high and low dose areas inside the hybrid theatres. Only scatter resulting from common projections were measured as it was not possible to measure all gantry angles. Awareness of high and low exposure areas will lead to a safer environment for radiation workers.