:: ImPACT's ct dosimetry tool
:: CTDosimetry version 1.0.4
The ImPACT CTDosimetry spreadsheet will NOT work without the Monte Carlo data sets.
A new version of CTDosimetry (version 1.0.4) was made available for download in May 2011. Click here to obtain the download.
Version 1.0 added the ability to calculate effective doses according to ICRP 103 as well as the existing ICRP 60 method, added data for several more scanners as well as a number of other smaller changes (see below for full list). Version 1.0.2 was released in November 2009 and addressed some minor issues to ensure compatibility with Excel 2007. Version 1.0.3, released in August 2010, added information on the Philips Brilliance 40 and 64 scanners and corrects some minor errors elsewhere in the spreadsheet. Version 1.0.4, released in May 2011, fixes an error with relative CTDI for the Siemens Definition AS and adds narrow collimation data for the Philips Brilliance 40 and 64.
ImPACT are changing the model for incorporation of new data into the spreadsheet. Rather than relying on our evaluations for data we are working with the Institute of Physics and Engineering in Medicine's Diagnostic Radiology Special Interest Group (IPEM's DR SIG) to update the data. Read how you can contribute data below.
:: about the tool
One of the results of the ImPACT CT dose survey is scanner matching data that enables newer scanners to be used with the NRPB SR250 dose distribution data obtained from Monte Carlo calculations for older scanner models.
The scanner match data has been incorporated to allow calculation of organ and effective doses to patients undergoing CT scans.
This Excel spreadsheet is available to download for users of this site.
The spreadsheet does an equivalent job to CTDOSE - produced by the New Zealand National Radiation Laboratory - but allows the selection of most modern CT scanners.
The current version is 1.0.4
Please click here for an update history of the tool.
:: a request to users of CTDosimetry
ImPACT are changing the model for incorporation of new data into the spreadsheet. Rather than relying on our evaluations for data we are working with the Institute of Physics and Engineering in Medicine's Diagnostic Radiology Special Interest Group (IPEM's DR SIG) to update the data. We would like to invite users who have access to scanners that do not currently appear in CTDosimetry to make appropriate CTDI measurements and send their results to the DR SIG. If you would like to make measurements please download and use this form.
If you are wanting guidance on how to use the current spreadsheet to estimate the dose from 64 slice scanners, please read this document.
We currently have no data to match dual-source CT scanners.
If you are using Toshiba scanners for cardiac scanning, please read the relevant note in our update document.
To obtain the tool:
all users can download the most recent version of our tool - as a 'zipped' version of the MS Excel file - by completing the form below and clicking the
download document button. Please complete as many details as you
The spreadsheet also uses (unsigned) macros - Excel application security settings must be set to medium in order to allow them to work.
We have tested it extensively and regularly check for viruses - but we would, of course, recommend that you use all due dilligence before using the application. We can not take any liability for the use of this tool and any subsequent losses.
We value feedback from users as to any bugs or usabililty issues that remain.
Monte Carlo data sources
Note that in order to use the CTDosimetry spreadsheet, you MUST obtain the NRPB SR250 dose data sets, and then these data sets should be be present in the same directory as the spreadsheet.
ImPACT do not supply the data files; these data sets can be purchased from authors via (Public Health England); the price is £50 sterling (GBP) plus tax (VAT), and postage; see their website for details. The spreadsheet will NOT work without these data sets.
Information submitted with your request is used to track the number of valid downloads and profile our user base. Access to the download is not restricted to those who fill in the form, but please leave 'anon' as your name if you are unwilling to disclose your real name - and please indicate your profession.
From version 1.0, the user can select whether to calculate effective dose using the ICRP 60 or the ICRP 103 weighting schemes.
From version 0.99r, guidance on paediatric effective dose is included, using
further data from the NRPB.
Versions 0.99l onwards, allow the user to select the x-ray beam collimation, and looks up the CTDI at that collimation. This is important for multi-slice scanners, as CTDI can vary quite widely with selected collimation.
CTDosimetry.xls also includes automatic calculation of weighted CTDI and dose-length product (DLP) values. See below for a full list of the changes included in each version of the spreadsheet.
Full update list
- Version 1.0.4 27/05/11
- Version 1.0.4, released in May 2011, fixes an error with relative CTDI for the Siemens Definition AS and adds narrow collimation data for the Philips Brilliance 40 and 64.
- Version 1.0.3 24/08/10
- Version 1.0.3, released in August 2010, adds information on the Philips Brilliance 40 and 64 scanners and corrects some minor errors elsewhere in the spreadsheet.
- Version 1.0.2 16/11/09
- Changed VBA code to avoid Excel 2007 crash: Phantom worksheet unprotected before changing the size/position of the rectangle indicating the scan range
- Version 1.0.1 04/11/09
- Modified VBA code for phantom range calculation to avoid crash in Excel 2007 on some machines
- Version 1.0 28/08/09
- Added ability to calculate effective dose according to ICRP 60 or ICRP 103, incorporating new weighted and remainder organs and weighting factors
- Removed patient sex selection box. All doses now listed for hermaphrodite phantom, with sex dependent organs listed separately
- Added eye lenses to phantom diagram, and lens dose to ScanCalculation worksheet
- Changed calculation of colon dose from LLI to mass weighted mean of ULI and LLI, and removed ULI from ICRP60 remainder organs, as recommended by ICRP69
- Changed dose to prostate from LLI to bladder (Prostate not in SR250, bladder is closer match)
- Added Philips Big Bore and Siemens Definition AS
- Corrected CTDIair values for Toshiba Aquilion (were quoted for 16, not 8 mm collimation)
- Finally bumped version number to 1.0!
- Version 0.99x 20/01/06
- Added LightSpeed RT (meant for 0.99w, but data was under review and removed before publication)
- Added LightSpeed VCT
- Version 0.99w 16/05/05
- Fixed problem when small ranges are used (< 5 mm), which start and end at non integer slab positions within a single slab
- Added GE LightSpeed Pro 16, LightSpeed RT, Siemens Sensation Open and Sensation 64
- Added Philips Brilliance 16 and Brilliance 16 Power to description of Mx8000 IDT data
- Updated links to NRPB SR250, which is now part of the HPA (www.hpa.org.uk)
- Updated some of the text in the Introduction to reflect changes over recent versions
- Version 0.99v 17/06/2004
- Changed nCTDIw cell to be editable, and added a 'look up' button
- Added Siemens Emotion 6 and Sensation 10
- Added CTDI information for Siemens Emotion Duo at 80 and 110kV
- Improved MCSET load routine to avoid odd errors. Thanks to Ed McDonagh, Royal Marsden
- Version 0.99u 12/12/2003
- Fixed error for scanners with more than 10 collimation options, where incorrect relative CTDI was chosen
- Fixed error with international locations that use '.' as a thousands separator
- Added Philips Aura CTDI data and 135kV data for GE Sytec
- Version 0.99t 24/07/2003
- Relative CTDI at 1 x 1.25mm corrected for the LightSpeed Plus
- Added CTDI data for Toshiba Aquilion 16 and Philips Mx8000 IDT
- Modified collimation data for GE NX/i / ZX/i and Philips AV to allow correct selection
- Version 0.99s 07/05/2003
- Corrected errors in Mx8000 data. Head phantom data and body 140kV data updated.
- Version 0.99r 02/04/2003
- Added 'Paediatric' worksheet, giving information on doses to children relative to adults
- Separated organ and effective dose calculations to the new 'DoseCalculations' worksheet
- Improved rounding of results so that only two significant figures are displayed for calculated organ and effective doses.
- Version 0.99q 20/02/2003
- Added CTDI data for Toshiba Asteion Multi, pre and post 2002, and Toshiba Asteion Dual.
- Duplicated Marconi Mx8000 and AcQSim data so they are also listed as Philips scanners.
- Version 0.99p 17/02/2003
- Removed typographical error on 'Collimation' worksheet that stops correct selection of CTDI at different collimations for the LightSpeed Ultra and LightSpeed 16
- Version 0.99o 28/01/2003
- Fixed error on Excel 97, which crashed with decimal separator code introduced in 0.99m
- Version 0.99n 17/01/2003
- Included CTDI data for Siemens Sensation 4, Sensation 16, GE LightSpeed Ultra and LightSpeed 16
- Changed Visual Basic code to avoid use of absolute references to cells on selections worksheet
- Version 0.99m 1/07/2002
- Fixed problem with computers with , as decimal separator having problems importing MC data
- Moved organ dose calculation data from ScanCalculation to Selections
- Included a cell showing CTDIw in ScanCalculation
- Updated nCTDIw calculation to include relative CTDI at different collimations
- Version 0.99l 17/06/2002
- Added data and selector for relative CTDIs at different collimations
- Updated GE LightSpeed match to include LightSpeed Plus
- Added CTDI data for Siemens Emotion Duo
- Version 0.99k 24/01/2002
- Incorporated CTDI values for Philips AcQsim scanner.
- Updated CTDI values for GE LightSpeed, and Toshiba Aquilion Multi
- Version 0.99j 23/10/2001
- Minor fix to 0.99i to recognise data sets 301-323 as being loaded (not relevant for most users)
- Version 0.99i 19/10/2001
- Added calculation of CTDIw and DLP values
- Included scanner matching data for GE ZX/i and NX/i
- Modified ScanCalculation!C11 to account for early versions of SR250 that number the data sets 301-323 rather than 1-23.
- Version 0.99h 30/4/2001
- Changed mAs/slice to mAs/rotation in ScanCalculation
- Updated LightSpeed and Aquilion results to use correct CTDIair for Body filter
- Version 0.99g 20/2/2001
- Corrected definition of pitch in Introduction.
- Added 'Scan Description / Comments' box to ScanCalculation
- Version 0.99f 15/2/2001
- Removed 'actual' kV setting from ScanCalculation, as match and actual kV should be identical
- Changed remainder organ calculation so that organ is included if the dose is greater than or equal to the maximum dose to listed radiosensitive organs
- Pointed out the potential problem with decimal points in 'Introduction'
- Version 0.99e 10/10/2000
- Introduced version worksheet to detail changes in different versions of CTDosimetry.xls (changes log)
- Added information for Siemens Volume Acces and Volume Zoom
- Fixed CTDI lookup formula to correctly look up Head CTDI in air
- Updated web links to new ImPACT web site at www.impactscan.org