Decimal separator in TPC
Background
Blood and regional PET data in Turku PET Centre are saved in ASCII file format (File format (DFT) of time-radioactivity curves), containing decimal numbers. The decimal separator is a symbol used to mark the boundary between the integral and the fractional parts of a decimal numeral. Terms implying the symbol used are decimal point and decimal comma. Both representations are accepted by SI, depending on the country.
Finland, Italy, Germany and France belong to the comma countries. United Kingdom, United States and Japan belong to the dot countries, and the programming tools and software for PET scanners and other devices have largely been developed there. Therefore, software in the PET field commonly assumes that decimal point is used, although modern software can be adapted to use the local separator.
Convention in TPC
At the present moment, most data analysis software in TPC writes decimal numbers with decimal point. Increasingly, "in-house" software can read data files using either comma or dot separator; dot separator is always accepted.
Problems
1. Files are produced with Windows software with comma separator
Problem is introduced, when Windows software (for example Excel), by default, uses local separator, which is comma in Finland. When these files are saved and used by analysis tools that assume decimal points, only the integer part of the decimal number may actually be read and the fractional part may be discarded, or, if you are lucky, program execution stops with an error.
Solution
Change the decimal separator setting in Windows from the control panel, or you can override the Windows decimal separator setting only in Excel, if you like. Note that in hospital network you may need to do this change again once a while.
2. Data with period as decimal separator are not imported correctly in Excel
Windows software is, by default, assuming that data files that you try to import are using local separator, which is comma in Finland. Our data files normally have dot separators, therefore the data is not imported correctly.
Solution #1
Change the decimal separator setting in Windows from the control panel, or you can override the Windows decimal separator setting only in Excel, if you like.
Solution #2
Use the latest versions of dft2html or dft2html to convert data files into XHTML table format and import those in Excel.
