J Med Phys Close
 

Figure 10: (a) An indication of the variation of out-of-field dose from a Siemens Primus as it varies with field size (shaped with jaws, full MLC retraction). Close to the primary field, the doses from the larger fields are greater, but this difference decreases with increasing distance from the field edge. (b) An illustration of the difference in out-of-field dose depending on energy mode. The out-of-field doses in 6-MV mode are consistently greater than in 18-MV mode. The data shown is adapted from Mazonakis and Zacharopolou[20]

Figure 10: (a) An indication of the variation of out-of-field dose from a Siemens Primus as it varies with field size (shaped with jaws, full MLC retraction). Close to the primary field, the doses from the larger fields are greater, but this difference decreases with increasing distance from the field edge. (b) An illustration of the difference in out-of-field dose depending on energy mode. The out-of-field doses in 6-MV mode are consistently greater than in 18-MV mode. The data shown is adapted from Mazonakis and Zacharopolou<sup>[20]</sup>