# How to change Dose (X-axis) increments on a Dose-Volume-Histogram?

**URL:** <https://discourse.slicer.org/t/how-to-change-dose-x-axis-increments-on-a-dose-volume-histogram/41505>\
**Category:** Support\
**Tags:** dicom, radiotherapy, rtdose\
**Created:** [February 5, 2025, 2:18am UTC](https://discourse.slicer.org/t/how-to-change-dose-x-axis-increments-on-a-dose-volume-histogram/41505 "2025-02-05T02:18:42Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Jeremy\_Fockenier](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/jeremy_fockenier/32/77766_2.png) [@Jeremy\_Fockenier](https://discourse.slicer.org/u/Jeremy_Fockenier)\
**Post date:** [February 5, 2025, 2:18am UTC](https://discourse.slicer.org/t/how-to-change-dose-x-axis-increments-on-a-dose-volume-histogram/41505/1 "2025-02-05T02:18:42Z")

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Hello fellow Slicers,

I am currently testing Monte-Carlo simulations on a synthetic lung with a proton beam (all input files are in DICOM) and am trying to output a DVH file. However, since the DVH program seems to only register voxel doses on a 0.1 Gy increment and my max voxel dose is much below that, I end up with a problem : my DVH table simply states that 100% of the selected volume receives at least 0 Gy and 0% of that same volume receives 0.1 Gy.

Is there a way to change the default increments of 0.1 Gy?

Thanks in advance,

Jeremy

 ![Capture d’écran du 2025-02-04 15-37-01](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/6/c/6c5147e9558b77451bb1a29e9cc737ff5b70b03b.png)

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**Author:** ![Jeremy\_Fockenier](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/jeremy_fockenier/32/77766_2.png) [@Jeremy\_Fockenier](https://discourse.slicer.org/u/Jeremy_Fockenier)\
**Post date:** [March 25, 2025, 6:57pm UTC](https://discourse.slicer.org/t/how-to-change-dose-x-axis-increments-on-a-dose-volume-histogram/41505/2 "2025-03-25T18:57:59Z")

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I have since resolved this issue thanks to this answer to a previous question :

> [@Dose accumulation weighting SlicerRT](https://discourse.slicer.org/t/dose-accumulation-weighting-slicerrt/4648/7):
>
> By downscaling the dose by a factor of 33.3x, computing the histogram, and then upscaling the result, you essentially scale up histogram quantization error by 33.3x. To maintain error at the same level, despite of this aggressive scaling, you need to set a smaller histogram bin width (=DVH step size). You can get current step size by opening the Python console (Ctrl-3) and typing: slicer.modules.dosevolumehistogram.logic().GetStepSize() To set a new value, type for example this: slicer.modul…

Jeremy