Research Article
An Empirical Model for Describing the Small Field Penumbra in Radiation Therapy
Table 1
The coplanar penetration depth
(
ϖ) and e
−μϖ on the right-side penumbra after double exposures.
| Distance from central axis of point d on the x axis (cm) | Gantry angles | 0° | 30° | 45° | 60° | 90° | | e−μϖ | | e−μϖ | | e−μϖ | | e−μϖ | | e−μϖ |
| 0 | 11.00 | 0.95223# | 11.00 | 0.95223 | 11.00 | 0.95223 | 11.00 | 0.95223 | 11.00 | 0.95223 | 0.1 | 11.00 | 0.95223 | 10.95 | 0.95233 | 10.93 | 0.95238 | 10.91 | 0.95241 | 10.90 | 0.95244 | 0.2 | 11.00 | 0.95223 | 10.90 | 0.95244 | 10.86 | 0.95253 | 10.83 | 0.95260 | 10.80 | 0.95265 | 0.3 | 11.00 | 0.95223 | 10.85 | 0.95255 | 10.79 | 0.95268 | 10.74 | 0.95278 | 10.70 | 0.95286 | 0.4 | 10.99 | 0.95223 | 10.80 | 0.95266 | 10.71 | 0.95283 | 10.65 | 0.95296 | 10.60 | 0.95308 | 0.5 | 10.99 | 0.95223 | 10.74 | 0.95277 | 10.64 | 0.95298 | 10.56 | 0.95315 | 10.50 | 0.95329 | 0.6 | 10.99 | 0.95223 | 10.69 | 0.95287 | 10.57 | 0.95313 | 10.48 | 0.95333 | 10.40 | 0.95350 | 0.7 | 10.98 | 0.95223 | 10.64 | 0.95298 | 10.50 | 0.95329 | 10.39 | 0.95352 | 10.30 | 0.95371 | 0.8 | 10.98 | 0.95223 | 10.58 | 0.95309 | 10.42 | 0.95344 | 10.30 | 0.95370 | 10.20 | 0.95393 | 0.9 | 10.97 | 0.95223 | 10.53 | 0.95321 | 10.35 | 0.95359 | 10.21 | 0.95389 | 10.10 | 0.95414 | 1 | 10.96 | 0.95223 | 10.47 | 0.95332 | 10.27 | 0.95375 | 10.12 | 0.95407 | 10.00 | 0.95435 | 1.1 | 10.96 | 0.95223 | 10.42 | 0.95343 | 10.20 | 0.95390 | 10.04 | 0.95426 | 9.90 | 0.95456 | 1.2 | 10.95 | 0.95223 | 10.36 | 0.95354 | 10.13 | 0.95406 | 9.95 | 0.95445 | 9.80 | 0.95477 | 1.3 | 10.94 | 0.95223 | 10.30 | 0.95365 | 10.05 | 0.95421 | 9.86 | 0.95463 | 9.70 | 0.95499 | 1.4 | 10.93 | 0.95223 | 10.25 | 0.95377 | 9.97 | 0.95437 | 9.77 | 0.95482 | 9.60 | 0.95520 | 1.5 | 10.92 | 0.95223 | 10.19 | 0.95388 | 9.90 | 0.95452 | 9.68 | 0.95501 | 9.50 | 0.95541 | 1.6 | 10.91 | 0.95223 | 10.13 | 0.95400 | 9.82 | 0.95468 | 9.59 | 0.95519 | 9.40 | 0.95562 | 1.7 | 10.90 | 0.95223 | 10.07 | 0.95411 | 9.75 | 0.95483 | 9.50 | 0.95538 | 9.30 | 0.95584 |
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#Data are calculated from ( ) by using e−μϖ, μ = 0.00494 cm −1 at 6 MV in water. |