# TDF Plan: Equivalent Fractionations

To compare the acute biological effects of a regimen consisting of 30 fractions of 200 cGy with a regimen employing a different number of fractions, simply enter the 30 fraction regimen as IMR course 1 (exclude courses 2 through 8 if necessary) in the IMR group of the TDF Plan window. To find a biologically equivalent course enter the different number of fractions in the Equivalent Single Course (ESC) window. The ESC calculator will display the dose per fraction required to match the IMR BED using the number of fractions entered in the ESC calculator. The button to open the ESC calculator window is located in the upper right corner of the IMR group box. The calculated dose per fraction and total dose for the new fractionation schedule is displayed in the ESC group, and the nearest achievable BED to that of the IMR is displayed. You may optionally enter any target BED value should you wish to by deselecting the "Match IMR BED" checkbox. The BED in the ESC group may not precisely match the target BED because the dose per fraction (cGy) is constrained by the program to be an integer value.

Example 1: (Windows Vista version) For example, set the number of ESC fractions to 15. The dose per fraction (354.4 cGy/frac.) and total dose (5316 cGy) required to match the IMR BED of 72.00 Gy(10.0) are immediately calculated for you. | Example 2: CyberKnife (MacOSX version) The ESC window also includes a presets menu which will automatically configure all of the ESC settings for certain calculations (e.g. 5 fraction CyberKnife radiosurgery). You may optionally schedule the treatment dates for the ESC in the Course Calendar if you wish. You can print the resulting calculation by selecting Print from the File menu or from the Documents Preview window.

Return to: BED Calculations