[Rtk-users] Hounsfield Unit Conversion - New User

[Chao Wu]

And be aware that --wpc receives polynomial coefficients, and if you only
specify one number this will become the constant term only, which is
probably not your intent.
Regards, Chao


2018-02-19 7:39 GMT+01:00 Simon Rit <simon.rit at creatis.insa-lyon.fr>:

> Hi,
> To convert to HU, you need to measure a phantom with water and air and to
> apply the formula for HU conversion (see wikipedia
> <https://en.wikipedia.org/wiki/Hounsfield_scale>). Note that due to
> scatter in (Elekta) cone-beam CTs, you will have difficulties in doing this
> conversion due to strong artifacts.
> The --wpc coefficients can allow you to apply the slope of this formula
> but the intercept must be subtracted after reconstruction. We illustrate
> here <http://wiki.openrtk.org/index.php/WaterPreCorrection> how to use
> wpc.
> Good luck,
> Simon
>
> On Mon, Feb 19, 2018 at 1:01 AM, muhammad waqar <
> muhammad.s.waqar at gmail.com> wrote:
>
>> Hello all,
>>
>> I'm a new user to ITK/RTK and I'm having a few issues:
>>
>> Following the ElektaReconstruction steps on the wiki, I was able to
>> reconstruct my scan. However, the window and level are still in attenuation
>> coefficients. How can I convert my scan to Hounsfield Units?
>>
>> Whenever I put in any value for --wpc in RTKFDK (I've tried values from
>> 0.015-150) my recon results in a 'blank' as is attached below.
>>
>> Any help in resolving this would be great.
>>
>> Kindly,
>> -Waqar Muhammad
>> Carleton University
>>
>>
>> ​
>> ᐧ
>>
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>>
>
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