Key concept: Parameters specified with the GIMP keyword determines the putative relationship between random mutational events and the onset of genomic instability.Tip: Combinations of PGH, PGA, and NCG that yield the same value for PGH*PGA*NCG produce approximately the same level of genomic instability and, ultimately, neoplastic transformation. The NCM parameter can have a dramatic effect on the shape of the cell transformation curve as a function of delivered dose (e.g., try NCM=1, 2 or 3).
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Example 14.1 The random mutation events leading to genomic instability per surviving fraction (EGI/SF) and transformation frequency per survivor (TPS) for variations in the number of critical genes (NCG) (e.g., rmrsim8.inp -> rmrsim8.out).  Variation of EGI/SF with the absorbed single fraction radiation dose. Comments: The degree of genomic instability (represented by EGI/SF) increases with increasing absorbed dose and NCG.  Variation of TPS with the absorbed single fraction radiation dose Comments: The behavior of transformation frequency per survivor (TPS) is similar to the degree of genomic instability shown in the previous figure. Suggested problems- Without performing any calculations (using the definitions of the terms), predict the trends of EGI/SF and TPS for increasing PGA, PGH and NCM.
- Appropriately modify and run the input file given in Example 14.1 to check your answers for Problem 1.
- Obtain the time variation of TPS is obtained after an acute single dose exposure of 6 Gy at10,000 Gy/h. Run your input file using VC, plot the results and elaborate.
- How different would the transformation frequency per survivor be if the same dose assumed in problem 3 is delivered as a split dose with a time gap of 10 hours? Assume the same dose rate.
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