# The direction of x and y jaw position in Beams Module

**URL:** <https://discourse.slicer.org/t/the-direction-of-x-and-y-jaw-position-in-beams-module/5226>\
**Category:** Support\
**Created:** [December 30, 2018, 8:08am UTC](https://discourse.slicer.org/t/the-direction-of-x-and-y-jaw-position-in-beams-module/5226 "2018-12-30T08:08:38Z")\
**Posts on this page:** 10\
**Page:** 1

<div class="post-metadata">

**Author:** ![aseman](https://avatars.discourse-cdn.com/v4/letter/a/c0e974/32.png) [@aseman](https://discourse.slicer.org/u/aseman)\
**Post date:** [December 30, 2018, 8:08am UTC](https://discourse.slicer.org/t/the-direction-of-x-and-y-jaw-position-in-beams-module/5226/1 "2018-12-30T08:08:38Z")

</div>

Slicer version:4.8.1  
Hi 3D slicer experts and all  
In Beams module for Geometry Tab, the x jaw position and y jaw position are in the direction of which axes respectively? In the other words SI or AP or RL axes?  
Thanks a lot

---

<div class="post-metadata">

**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [December 30, 2018, 2:51pm UTC](https://discourse.slicer.org/t/the-direction-of-x-and-y-jaw-position-in-beams-module/5226/2 "2018-12-30T14:51:39Z")

</div>

In general, in Slicer, first (x) axis is L-R, second (y) axis is A-P direction. @cpinter or @gcsharp may comment on the axes directions in this specific case.

Use latest stable version (Slicer-4.10).

---

<div class="post-metadata">

**Author:** ![gcsharp](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/gcsharp/32/863_2.png) [@gcsharp](https://discourse.slicer.org/u/gcsharp)\
**Post date:** [December 31, 2018, 2:04pm UTC](https://discourse.slicer.org/t/the-direction-of-x-and-y-jaw-position-in-beams-module/5226/3 "2018-12-31T14:04:21Z")

</div>

Hm, it looks like the beams module does not follow IEC conventions. Thank you for the alert.

---

<div class="post-metadata">

**Author:** ![cpinter](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/cpinter/32/7995_2.png) [@cpinter](https://discourse.slicer.org/u/cpinter)\
**Post date:** [December 31, 2018, 5:23pm UTC](https://discourse.slicer.org/t/the-direction-of-x-and-y-jaw-position-in-beams-module/5226/4 "2018-12-31T17:23:33Z")

</div>

I fixed the issue as discussed with @gcsharp, see [https://github.com/SlicerRt/SlicerRT/issues/100](https://github.com/SlicerRt/SlicerRT/issues/100).  
It should be fine in tomorrow’s nightly or later (but NOT in 4.10, only in 4.10.1 when released).

---

<div class="post-metadata">

**Author:** ![aseman](https://avatars.discourse-cdn.com/v4/letter/a/c0e974/32.png) [@aseman](https://discourse.slicer.org/u/aseman)\
**Post date:** [January 3, 2019, 6:13am UTC](https://discourse.slicer.org/t/the-direction-of-x-and-y-jaw-position-in-beams-module/5226/5 "2019-01-03T06:13:46Z")

</div>

Hi  
Thank you for your guidelines.I have another question ! I import the RT Plans from Treatment Planning System (TPS). In TPS, the x is in L-R and y is in S-I directions. Is it possible to match the x and y directions in these two systems (i.e TPS and 3D Slicer)?  
Thanks a lot

---

<div class="post-metadata">

**Author:** ![cpinter](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/cpinter/32/7995_2.png) [@cpinter](https://discourse.slicer.org/u/cpinter)\
**Post date:** [January 3, 2019, 4:01pm UTC](https://discourse.slicer.org/t/the-direction-of-x-and-y-jaw-position-in-beams-module/5226/6 "2019-01-03T16:01:50Z")

</div>

We talked with @gcsharp and although the axes were right after my fix, the directions weren’t. I fixed them now.

To use this fixed version, please install the “Nightly Build” tomorrow or any day after: [https://download.slicer.org/](https://download.slicer.org/)

---

<div class="post-metadata">

**Author:** ![gcsharp](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/gcsharp/32/863_2.png) [@gcsharp](https://discourse.slicer.org/u/gcsharp)\
**Post date:** [January 3, 2019, 5:00pm UTC](https://discourse.slicer.org/t/the-direction-of-x-and-y-jaw-position-in-beams-module/5226/7 "2019-01-03T17:00:19Z")

</div>

Hi Azam,

Now everything should match between Slicer and your TPS after Csaba’s fix (tomorrow or next day nightly build). For gantry 0, couch 0, and HFS treatment position, you should see x increase from R to L, and y increase from I to S. Please let us know if you have any more problem and thank you for your report.

---

<div class="post-metadata">

**Author:** ![aseman](https://avatars.discourse-cdn.com/v4/letter/a/c0e974/32.png) [@aseman](https://discourse.slicer.org/u/aseman)\
**Post date:** [February 9, 2019, 5:25am UTC](https://discourse.slicer.org/t/the-direction-of-x-and-y-jaw-position-in-beams-module/5226/8 "2019-02-09T05:25:25Z")

</div>

Hi 3D Slicer experts and all  
I’ m sorry for my question .but can you tell me that for gantry 0 and collimator 0 , what is the direction of x and y jaw respectively for slicer 4.10.1 (Linux)?  
Thanks a lot

---

<div class="post-metadata">

**Author:** ![cpinter](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/cpinter/32/7995_2.png) [@cpinter](https://discourse.slicer.org/u/cpinter)\
**Post date:** [February 9, 2019, 3:37pm UTC](https://discourse.slicer.org/t/the-direction-of-x-and-y-jaw-position-in-beams-module/5226/9 "2019-02-09T15:37:57Z")

</div>

After our recent fixes, which are included in 4.10.1, everything should conform to the DICOM standard:

1. IEC: [http://dicom.nema.org/medical/DICOM/current/output/chtml/part03/sect\_C.8.8.25.6.html](http://dicom.nema.org/medical/DICOM/current/output/chtml/part03/sect_C.8.8.25.6.html)
2. Beams (see jaws at ‘beam limiting device’): [http://dicom.nema.org/medical/DICOM/current/output/chtml/part03/sect\_C.8.8.14.html](http://dicom.nema.org/medical/DICOM/current/output/chtml/part03/sect_C.8.8.14.html)

---

<div class="post-metadata">

**Author:** ![aseman](https://avatars.discourse-cdn.com/v4/letter/a/c0e974/32.png) [@aseman](https://discourse.slicer.org/u/aseman)\
**Post date:** [February 15, 2019, 1:09pm UTC](https://discourse.slicer.org/t/the-direction-of-x-and-y-jaw-position-in-beams-module/5226/10 "2019-02-15T13:09:11Z")

</div>

Hi  
Thank you very much for your guidelines. Briefly , by considering the 3D view and slice viewers , for Gantry 0 and collimator 0 , the x jaw position increases in S-I direction and y jaw position increases in L-R direction. also, both the Gantry and collimator rotation are counter clockwise. is this statement true ?  
Thanks a lot