For most purposes, the end goal of ADCI software is to provide the estimated radiation dose (in Gy) of test samples. In order to generate the estimated dose, processed samples and a calibration curve must be present. Alternatively, dose estimation can also be performed on dicentric frequency alone without the presence of a curve.
When performing dose estimation, it is generally preferable to use the dose estimation wizard instead of manually importing/entering values as described on this page. The wizard seamlessly prompts you to select a calibration curve and processed samples and applies the same image selection model to the samples that was used when generating the curve. However, to examine dicentric frequency alone without the presence of a curve, the dose estimation wizard cannot be used and a method to do so is described below.
The dose estimation wizard guides the user through the necessary steps to estimate the dose of a set of processed samples. While using the wizard the sample name, SVM sigma value, and dicentric frequency are automatically prepopulated based on the selected samples. The steps within the wizard can also be performed manually if desired, those steps are described below.
Whether dicentric frequencies are to be entered manually or by examining existing processed samples, a calibration curve is necessary for dose estimation. Highlight the appropriate calibration curve within the list of curves in the main GUI and click the icon.
Dicentric chromosome counts are influenced by the SVM sigma value. If overall dicentric chromosome counts within test samples and calibration samples are made based on different SVM sigma values, the results may not be as accurate.
It is not recommended to manually enter DC frequency values for dose estimation when using a calibration curve generated by ADCI software. If the curve coefficients have been entered manually then it is permissible to manually enter DC frequency values as well. If the curve was generated using ADCI software it has an associated SVM sigma value (as seen at the bottom of the dialog). Higher SVM sigma values find more DCs than lower SVM sigma values but still generally underestimate DC counts when compared to expert manual examination1). Manual counts of DCs are of course not associated with any SVM sigma value. Therefore, manually entering DC counts and using a curve generated using an SVM sigma value will not generate results accurately.
Two factors which contribute to uncertainty present in dose estimation are the Poisson nature of dicentric chromosome yield and uncertainties related to the calibration curve. These types of uncertainty are taken into account based on settings within [Settings (menu bar) → Statistics Options]. Dose estimate upper confidence limits (UCL) and lower confidence limits (LCL) are shown on the dose estimation plot as smaller dotted lines. The LCL of a dose estimate is always greater than or equal to 0. The UCL of a dose estimate will always be less than the upper bound of the curve or LCL of the curve when curve confidence intervals are taken into account. If the UCL of a dose estimate is above this value, it will be listed as “out of bounds” in the console.
Calculates the exact 95% confidence interval of the Poisson distribution, resulting in upper and lower bounds of DC frequency. DC frequency upper bound is intersected with the calibration curve to calculate dose estimate UCL. DC frequency lower bound is intersected with the calibration curve to calculate dose estimate LCL.
Confidence intervals of the curve are used to calculate a dose estimate range. The DC frequency reading is intersected with the calibration curve UCL and LCL to generate the dose estimate LCL and UCL respectively. Note a dicentric frequency may never intersect the lower limit of the calibration curve within a specified upper limit of the curve, even if it does intersect the calibration curve. If they do not intersect, the UCL is listed as out of bounds.
First calculates the exact 95% confidence interval of the Poisson distribution, resulting in upper and lower bounds of DC frequency. The lower bound of DC frequency is intersected with the calibration curve UCL to obtain the dose estimate LCL. Similarly, the upper bound of DC frequency is intersected with the calibration curve LCL to obtain the dose estimate UCL. Note a dicentric frequency may never intersect the lower limit of the calibration curve within a specified upper limit of the curve, even if it does intersect the calibration curve. If they do not intersect, the UCL is listed as out of bounds.