TABLE III.
Tissue phantom ratios (TPRs) for 6-MV photons (d0 = 10 cm).
| Field size | 4 × 4 | 5 × 5 | 6 × 6 | 7 × 7 | 8 × 8 | 9 × 9 | 10 × 10 | 11 × 11 | 12 × 12 | 13 × 13 | 14 × 14 | 15 × 15 | 16 × 16 | 17 × 17 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Depth | ||||||||||||||
| 1.5 | 1.390 | 1.364 | 1.340 | 1.323 | 1.313 | 1.302 | 1.291 | 1.281 | 1.273 | 1.267 | 1.261 | 1.256 | 1.251 | 1.246 |
| 2.0 | 1.381 | 1.360 | 1.336 | 1.317 | 1.307 | 1.296 | 1.286 | 1.275 | 1.267 | 1.260 | 1.255 | 1.251 | 1.246 | 1.241 |
| 2.5 | 1.360 | 1.338 | 1.321 | 1.305 | 1.292 | 1.281 | 1.270 | 1.261 | 1.254 | 1.247 | 1.241 | 1.237 | 1.232 | 1.228 |
| 3.0 | 1.335 | 1.318 | 1.298 | 1.283 | 1.273 | 1.263 | 1.253 | 1.244 | 1.238 | 1.232 | 1.227 | 1.223 | 1.219 | 1.214 |
| 3.5 | 1.311 | 1.296 | 1.279 | 1.266 | 1.257 | 1.247 | 1.237 | 1.228 | 1.221 | 1.216 | 1.212 | 1.209 | 1.205 | 1.201 |
| 4.0 | 1.286 | 1.275 | 1.258 | 1.244 | 1.236 | 1.229 | 1.221 | 1.213 | 1.208 | 1.202 | 1.198 | 1.194 | 1.191 | 1.187 |
| 4.5 | 1.263 | 1.252 | 1.238 | 1.226 | 1.219 | 1.212 | 1.204 | 1.197 | 1.192 | 1.188 | 1.183 | 1.180 | 1.177 | 1.173 |
| 5.0 | 1.240 | 1.230 | 1.217 | 1.207 | 1.200 | 1.193 | 1.187 | 1.181 | 1.177 | 1.172 | 1.169 | 1.167 | 1.164 | 1.161 |
| 5.5 | 1.216 | 1.207 | 1.196 | 1.187 | 1.181 | 1.176 | 1.170 | 1.164 | 1.159 | 1.155 | 1.152 | 1.150 | 1.148 | 1.145 |
| 6.0 | 1.192 | 1.183 | 1.174 | 1.166 | 1.162 | 1.157 | 1.152 | 1.147 | 1.143 | 1.139 | 1.137 | 1.135 | 1.133 | 1.131 |
| 6.5 | 1.167 | 1.161 | 1.152 | 1.146 | 1.143 | 1.139 | 1.133 | 1.127 | 1.124 | 1.122 | 1.120 | 1.119 | 1.117 | 1.115 |
| 7.0 | 1.142 | 1.135 | 1.129 | 1.125 | 1.122 | 1.118 | 1.114 | 1.110 | 1.107 | 1.105 | 1.103 | 1.100 | 1.098 | 1.096 |
| 7.5 | 1.119 | 1.112 | 1.106 | 1.102 | 1.098 | 1.095 | 1.092 | 1.090 | 1.088 | 1.086 | 1.085 | 1.083 | 1.082 | 1.081 |
| 8.0 | 1.094 | 1.089 | 1.084 | 1.082 | 1.079 | 1.077 | 1.074 | 1.071 | 1.069 | 1.067 | 1.066 | 1.066 | 1.065 | 1.065 |
| 8.5 | 1.072 | 1.067 | 1.062 | 1.061 | 1.060 | 1.058 | 1.055 | 1.052 | 1.051 | 1.050 | 1.050 | 1.050 | 1.049 | 1.049 |
| 9.0 | 1.047 | 1.045 | 1.041 | 1.040 | 1.039 | 1.038 | 1.037 | 1.035 | 1.035 | 1.035 | 1.034 | 1.034 | 1.033 | 1.033 |
| 9.5 | 1.023 | 1.020 | 1.019 | 1.020 | 1.020 | 1.019 | 1.017 | 1.016 | 1.017 | 1.017 | 1.017 | 1.017 | 1.016 | 1.016 |
| 10.0 | 1.000 | 1.000 | 1.000 | 1.000 | 1.000 | 1.000 | 1.000 | 1.000 | 1.000 | 1.000 | 1.000 | 1.000 | 1.000 | 1.000 |
| 10.5 | 0.980 | 0.979 | 0.979 | 0.981 | 0.982 | 0.982 | 0.982 | 0.982 | 0.983 | 0.984 | 0.985 | 0.985 | 0.985 | 0.985 |
| 11.0 | 0.960 | 0.959 | 0.959 | 0.961 | 0.962 | 0.963 | 0.964 | 0.964 | 0.965 | 0.965 | 0.966 | 0.967 | 0.969 | 0.970 |
| 11.5 | 0.939 | 0.940 | 0.939 | 0.941 | 0.943 | 0.945 | 0.946 | 0.947 | 0.948 | 0.950 | 0.951 | 0.952 | 0.953 | 0.953 |
| 12.0 | 0.919 | 0.919 | 0.918 | 0.921 | 0.923 | 0.925 | 0.927 | 0.929 | 0.931 | 0.933 | 0.934 | 0.936 | 0.937 | 0.938 |
| 12.5 | 0.896 | 0.897 | 0.897 | 0.901 | 0.904 | 0.906 | 0.908 | 0.909 | 0.912 | 0.915 | 0.917 | 0.918 | 0.918 | 0.918 |
| 13.0 | 0.877 | 0.876 | 0.877 | 0.882 | 0.885 | 0.888 | 0.889 | 0.891 | 0.893 | 0.897 | 0.900 | 0.901 | 0.902 | 0.903 |
| 13.5 | 0.856 | 0.857 | 0.858 | 0.863 | 0.868 | 0.870 | 0.873 | 0.875 | 0.877 | 0.880 | 0.883 | 0.885 | 0.887 | 0.888 |
| 14.0 | 0.838 | 0.840 | 0.840 | 0.846 | 0.850 | 0.853 | 0.855 | 0.856 | 0.859 | 0.863 | 0.867 | 0.870 | 0.872 | 0.874 |
| 14.5 | 0.818 | 0.822 | 0.823 | 0.828 | 0.832 | 0.835 | 0.838 | 0.841 | 0.845 | 0.848 | 0.852 | 0.855 | 0.857 | 0.860 |
| 15.0 | 0.801 | 0.804 | 0.806 | 0.811 | 0.815 | 0.819 | 0.822 | 0.824 | 0.828 | 0.832 | 0.836 | 0.839 | 0.842 | 0.844 |
| 16.0 | 0.768 | 0.771 | 0.773 | 0.781 | 0.785 | 0.788 | 0.791 | 0.793 | 0.797 | 0.802 | 0.806 | 0.809 | 0.811 | 0.813 |
| 17.0 | 0.733 | 0.737 | 0.739 | 0.746 | 0.752 | 0.756 | 0.760 | 0.762 | 0.766 | 0.770 | 0.775 | 0.779 | 0.782 | 0.784 |
| 18.0 | 0.701 | 0.704 | 0.706 | 0.714 | 0.720 | 0.724 | 0.727 | 0.731 | 0.735 | 0.740 | 0.746 | 0.750 | 0.753 | 0.756 |
| 19.0 | 0.671 | 0.675 | 0.675 | 0.683 | 0.689 | 0.693 | 0.697 | 0.701 | 0.706 | 0.712 | 0.717 | 0.722 | 0.725 | 0.728 |
| 20.0 | 0.642 | 0.647 | 0.648 | 0.656 | 0.663 | 0.667 | 0.672 | 0.675 | 0.679 | 0.685 | 0.691 | 0.696 | 0.698 | 0.701 |
| 21.0 | 0.616 | 0.619 | 0.621 | 0.630 | 0.637 | 0.642 | 0.646 | 0.649 | 0.653 | 0.657 | 0.663 | 0.668 | 0.672 | 0.676 |
| 22.0 | 0.590 | 0.593 | 0.593 | 0.603 | 0.612 | 0.616 | 0.619 | 0.622 | 0.626 | 0.632 | 0.639 | 0.645 | 0.648 | 0.651 |
| 23.0 | 0.565 | 0.570 | 0.568 | 0.575 | 0.585 | 0.590 | 0.595 | 0.597 | 0.600 | 0.605 | 0.612 | 0.619 | 0.623 | 0.626 |
| 24.0 | 0.541 | 0.546 | 0.544 | 0.550 | 0.559 | 0.564 | 0.569 | 0.572 | 0.576 | 0.581 | 0.588 | 0.594 | 0.598 | 0.601 |
| 25.0 | 0.517 | 0.524 | 0.522 | 0.529 | 0.539 | 0.543 | 0.547 | 0.550 | 0.553 | 0.558 | 0.565 | 0.572 | 0.576 | 0.579 |
| Field size | 18 × 18 | 19 × 19 | 20 × 20 | 21 × 21 | 22 × 22 | 24 × 24 | 26 × 26 | 28 × 28 | 30 × 30 | 32 × 32 | 34 × 34 | 36 × 36 | 38 × 38 | 40 × 40 |
| Depth | ||||||||||||||
| 1.5 | 1.241 | 1.237 | 1.232 | 1.228 | 1.224 | 1.218 | 1.212 | 1.207 | 1.204 | 1.200 | 1.196 | 1.192 | 1.189 | 1.186 |
| 2.0 | 1.236 | 1.231 | 1.226 | 1.222 | 1.218 | 1.211 | 1.205 | 1.201 | 1.199 | 1.195 | 1.192 | 1.188 | 1.185 | 1.181 |
| 2.5 | 1.223 | 1.219 | 1.215 | 1.211 | 1.207 | 1.200 | 1.194 | 1.190 | 1.188 | 1.185 | 1.182 | 1.179 | 1.176 | 1.173 |
| 3.0 | 1.210 | 1.206 | 1.203 | 1.199 | 1.195 | 1.189 | 1.184 | 1.179 | 1.176 | 1.173 | 1.170 | 1.167 | 1.164 | 1.162 |
| 3.5 | 1.197 | 1.193 | 1.189 | 1.186 | 1.182 | 1.177 | 1.172 | 1.168 | 1.166 | 1.163 | 1.160 | 1.157 | 1.155 | 1.152 |
| 4.0 | 1.184 | 1.181 | 1.177 | 1.174 | 1.171 | 1.166 | 1.161 | 1.158 | 1.155 | 1.152 | 1.150 | 1.148 | 1.145 | 1.143 |
| 4.5 | 1.170 | 1.167 | 1.164 | 1.161 | 1.158 | 1.153 | 1.149 | 1.146 | 1.144 | 1.142 | 1.139 | 1.137 | 1.135 | 1.132 |
| 5.0 | 1.157 | 1.154 | 1.151 | 1.148 | 1.145 | 1.141 | 1.138 | 1.135 | 1.133 | 1.131 | 1.129 | 1.127 | 1.124 | 1.122 |
| 5.5 | 1.142 | 1.139 | 1.136 | 1.134 | 1.132 | 1.129 | 1.126 | 1.123 | 1.120 | 1.118 | 1.116 | 1.114 | 1.112 | 1.111 |
| 6.0 | 1.128 | 1.126 | 1.123 | 1.121 | 1.118 | 1.115 | 1.111 | 1.109 | 1.107 | 1.106 | 1.104 | 1.103 | 1.101 | 1.099 |
| 6.5 | 1.113 | 1.111 | 1.109 | 1.107 | 1.105 | 1.102 | 1.099 | 1.096 | 1.094 | 1.093 | 1.091 | 1.090 | 1.088 | 1.087 |
| 7.0 | 1.094 | 1.093 | 1.092 | 1.091 | 1.089 | 1.087 | 1.085 | 1.083 | 1.082 | 1.081 | 1.080 | 1.078 | 1.077 | 1.076 |
| 7.5 | 1.079 | 1.078 | 1.077 | 1.076 | 1.074 | 1.072 | 1.069 | 1.067 | 1.066 | 1.065 | 1.064 | 1.063 | 1.062 | 1.062 |
| 8.0 | 1.063 | 1.062 | 1.061 | 1.060 | 1.059 | 1.058 | 1.056 | 1.054 | 1.052 | 1.051 | 1.049 | 1.048 | 1.048 | 1.048 |
| 8.5 | 1.048 | 1.047 | 1.045 | 1.044 | 1.043 | 1.042 | 1.041 | 1.040 | 1.039 | 1.038 | 1.038 | 1.037 | 1.037 | 1.036 |
| 9.0 | 1.032 | 1.032 | 1.032 | 1.031 | 1.031 | 1.029 | 1.028 | 1.027 | 1.026 | 1.026 | 1.026 | 1.025 | 1.025 | 1.024 |
| 9.5 | 1.016 | 1.016 | 1.016 | 1.015 | 1.015 | 1.014 | 1.014 | 1.013 | 1.013 | 1.014 | 1.014 | 1.014 | 1.014 | 1.013 |
| 10.0 | 1.000 | 1.000 | 1.000 | 1.000 | 1.000 | 1.000 | 1.000 | 1.000 | 1.000 | 1.000 | 1.000 | 1.000 | 1.000 | 1.000 |
| 10.5 | 0.986 | 0.986 | 0.986 | 0.986 | 0.985 | 0.985 | 0.985 | 0.986 | 0.986 | 0.986 | 0.987 | 0.987 | 0.988 | 0.988 |
| 11.0 | 0.970 | 0.971 | 0.971 | 0.971 | 0.972 | 0.972 | 0.972 | 0.972 | 0.973 | 0.973 | 0.974 | 0.975 | 0.975 | 0.975 |
| 11.5 | 0.954 | 0.955 | 0.955 | 0.956 | 0.956 | 0.957 | 0.959 | 0.960 | 0.960 | 0.960 | 0.960 | 0.960 | 0.961 | 0.961 |
| 12.0 | 0.938 | 0.938 | 0.939 | 0.939 | 0.940 | 0.941 | 0.943 | 0.945 | 0.945 | 0.945 | 0.945 | 0.946 | 0.946 | 0.947 |
| 12.5 | 0.920 | 0.921 | 0.922 | 0.924 | 0.925 | 0.927 | 0.929 | 0.931 | 0.932 | 0.932 | 0.933 | 0.933 | 0.934 | 0.935 |
| 13.0 | 0.904 | 0.905 | 0.906 | 0.908 | 0.909 | 0.911 | 0.913 | 0.915 | 0.916 | 0.917 | 0.918 | 0.920 | 0.921 | 0.922 |
| 13.5 | 0.890 | 0.891 | 0.892 | 0.894 | 0.895 | 0.898 | 0.901 | 0.903 | 0.904 | 0.905 | 0.905 | 0.906 | 0.907 | 0.908 |
| 14.0 | 0.876 | 0.877 | 0.879 | 0.880 | 0.881 | 0.883 | 0.885 | 0.887 | 0.889 | 0.891 | 0.892 | 0.894 | 0.895 | 0.897 |
| 14.5 | 0.861 | 0.863 | 0.864 | 0.866 | 0.867 | 0.869 | 0.872 | 0.874 | 0.876 | 0.877 | 0.878 | 0.880 | 0.881 | 0.883 |
| 15.0 | 0.846 | 0.848 | 0.849 | 0.851 | 0.853 | 0.856 | 0.859 | 0.862 | 0.864 | 0.865 | 0.867 | 0.868 | 0.870 | 0.871 |
| 16.0 | 0.815 | 0.818 | 0.820 | 0.822 | 0.825 | 0.829 | 0.833 | 0.837 | 0.839 | 0.840 | 0.842 | 0.843 | 0.845 | 0.846 |
| 17.0 | 0.787 | 0.789 | 0.792 | 0.794 | 0.796 | 0.801 | 0.805 | 0.809 | 0.812 | 0.814 | 0.815 | 0.816 | 0.818 | 0.820 |
| 18.0 | 0.758 | 0.761 | 0.763 | 0.765 | 0.768 | 0.773 | 0.777 | 0.782 | 0.786 | 0.787 | 0.789 | 0.791 | 0.793 | 0.795 |
| 19.0 | 0.730 | 0.733 | 0.736 | 0.739 | 0.741 | 0.746 | 0.751 | 0.756 | 0.760 | 0.762 | 0.764 | 0.766 | 0.769 | 0.771 |
| 20.0 | 0.703 | 0.706 | 0.709 | 0.712 | 0.715 | 0.721 | 0.727 | 0.732 | 0.736 | 0.739 | 0.742 | 0.744 | 0.747 | 0.749 |
| 21.0 | 0.679 | 0.682 | 0.685 | 0.687 | 0.690 | 0.695 | 0.701 | 0.707 | 0.713 | 0.716 | 0.718 | 0.720 | 0.722 | 0.725 |
| 22.0 | 0.653 | 0.655 | 0.658 | 0.661 | 0.664 | 0.670 | 0.677 | 0.683 | 0.689 | 0.692 | 0.694 | 0.696 | 0.698 | 0.700 |
| 23.0 | 0.628 | 0.631 | 0.634 | 0.636 | 0.639 | 0.645 | 0.652 | 0.659 | 0.665 | 0.668 | 0.670 | 0.672 | 0.674 | 0.676 |
| 24.0 | 0.603 | 0.606 | 0.609 | 0.612 | 0.615 | 0.622 | 0.629 | 0.636 | 0.642 | 0.646 | 0.648 | 0.650 | 0.651 | 0.654 |
| 25.0 | 0.582 | 0.584 | 0.587 | 0.591 | 0.594 | 0.600 | 0.607 | 0.615 | 0.621 | 0.626 | 0.628 | 0.629 | 0.630 | 0.633 |