Figure 1. (a) A set-up used for the measurements showing the head phantom and the ion chamber located in the central hole. The cylindrical phantom has a diameter of 16 cm and a length of 15 cm. The position of the top and bottom strips of radiochromic film is indicated with white circumferences (note that the bottom one cannot be seen because it is placed under the phantom. (b) The calibrated densitometer used to measure the optical density of the film strips. From: Experimental estimates of peak skin dose and its relationship to the CT dose index using the CTDI head phantom Radiat Prot Dosimetry. 2013;157(4):536-542. doi:10.1093/rpd/nct171 Radiat Prot Dosimetry | Published by Oxford University Press 2013. This work is written by (a) US Government employee(s) and is in the public domain in the US
Figure 2. Calibration curve for film in terms of PSD up to 200 mGy Figure 2. Calibration curve for film in terms of PSD up to 200 mGy. The optical density is shown in arbitrary units (a.u.). Uncertainty bars (horizontal bars) represent the variation of the various film readings to a fixed dose (see text). Note that for smaller PSD values the uncertainty bars are smaller than the symbols. From: Experimental estimates of peak skin dose and its relationship to the CT dose index using the CTDI head phantom Radiat Prot Dosimetry. 2013;157(4):536-542. doi:10.1093/rpd/nct171 Radiat Prot Dosimetry | Published by Oxford University Press 2013. This work is written by (a) US Government employee(s) and is in the public domain in the US
Figure 4. Beam profiles obtained from the films placed at the bottom of the phantom, produced with the highest mA s setting used for each scanner. The corresponding models for the CT units shown were GE Discovery Model CT750HD, Philips model iCT256, Siemens Definition and Toshiba Aquilion ONE. From: Experimental estimates of peak skin dose and its relationship to the CT dose index using the CTDI head phantom Radiat Prot Dosimetry. 2013;157(4):536-542. doi:10.1093/rpd/nct171 Radiat Prot Dosimetry | Published by Oxford University Press 2013. This work is written by (a) US Government employee(s) and is in the public domain in the US
Figure 3. The relationship between the displayed CTDI<sub>vol</sub> and PSD measured at the top and bottom surfaces of the head phantom. The uncertainty bars represent the variations observed from repeated measurements made with the film and ion chamber with a given set of scanning parameters (see text). The corresponding models for the CT units in the graph were: GE Discovery Model CT750HD, Philips model iCT256, Siemens Definition and Toshiba Aquilion ONE. From: Experimental estimates of peak skin dose and its relationship to the CT dose index using the CTDI head phantom Radiat Prot Dosimetry. 2013;157(4):536-542. doi:10.1093/rpd/nct171 Radiat Prot Dosimetry | Published by Oxford University Press 2013. This work is written by (a) US Government employee(s) and is in the public domain in the US