See also Epiqa Knowledgebase

Frequently asked questions:


Q: Which TPS and linac Epiqa supports?
At this moment Epiqa support all Varian linacs with Eclipse, Pinnacle, RayStation, Monaco, XiO and Oncentra MasterPlan TPS.

Q: Can I use Epiqa with Elekta or Siemens machine?
Elekta linacs are supported from Epiqa version  5.
We have no plans to support Siemens machines.

Q: Can I use Epiqa for in-vivo dosimetry?
Yes, you can use it with the patient but only to compare measured transit dose matrices day after day. At this moment we have no “prediction” of the expected image. We are working on the implementation which will allow us to calculate dose in patient.

Q: Is Epiqa FDA certified or does it have CE mark?
With the current features Epiqa is not considered as medical device (no patient involved) and so certification is not mandated. We are working on the certification.

Q: Can I use Epiqa together with the Varian’s Portal Dosimetry (PDIP)
Yes. You just need to provide Epiqa with the diagonal profile used for portal dosimetry calibration at the 4DTC console.

Q: If I buy Epiqa do I have to buy portal dosimetry option from Varian?
No. There is no need to buy portal dose prediction on the Eclipse side. On the linac side machine must support integrated image acquisition. All Varian linacs have this capability. It may be advantage to buy portal dosimetry acquisition option from Varian to have assurance of Varian’s service support of the integrated image acquisition.

Q: I have Clinac and Eclipse but I am a Mosaiq (IMPAC) user. Can I use Epiqa?
Yes. You export reference dose images from Eclipse normal way. On the linac side you would export the integrated images from the stand-alone Portal Vision.

Q: Can I use Epiqa with the Varian’s Halcyon system?
Yes. Epiqa v. 5.1 and higher supports also portal dosimetry images acquired by Halcyon system.

Q: I want to use demo data but I get error 114 – Permission denied. License nod valid or expired.
Demo data are used without any license. License is needed only for the evaluation of your patients. Epiqa always try to find in the data your institution ID and Linac ID. If you want to use Epiqa in demo mode, erase your license file from the license folder. But don`t forget to make a copy of your license file.

Q: Could you please explain me how I can use the Gaussian convolution tool?
This allows you to perform a Gaussian convolution on the PV measured data.
It can be effective to see the effect of the sampling of the data. In general, comparing Eclipse matrix (where you have a certain dose calculation grid) and the measurement where the resolution is higher, you can see differences due to the low dose sampling of calculation. Usually the agreement between a convoluted measurement and dose calculation matrices is higher- after a convolution, the measured dose distribution is smoother. Clearly, this tool has to be used carefully, thinking that you are delivering peaks and valleys that are not fully calculated. We would not suggest to use it to “improve” GAI results.
See Epiqa user experience on: Gaussian convolution in Epiqa

Q: When trying to analyse recently acquired Epiqa images I get the following error message: “…not a valid portal image”
1. Your problem is with portal imager position in acquired PV images. You are out of allowed limits. Acceptable tolerances are: vertical 2mm, lateral and longitudinal 1.5cm.
Only possibility is to acquire new PV images with correct imager position (0,0,0).

2. Your problem results from imager (portal vision) calibration, because your portal vision acquired images are Rescale Type “RD” and this type of images Epiqa cannot recognize.
In Epiqa you can load only two types of image scales:
Rescale type “US“ – it is scale type of RAW image, without CU calibration
Rescale type “CU” – it is scale type of dosimetric calibrated image = CU calibrated image.
So we suggest you to recalibrate your portal vision correctly and acquire new PV images.

Q: What is diagonal intensity profile?
Diagonal intensity profile is the same profile which you used during Varian´s portal dosimetry configuration. It is important to use the same diagonal intensity profile.
All information you can find in Epiqa users manual (Diagonal profile definition – using Varian´s portal dosimetry CU calibrated image)

Q: What means the number 6 in param file in section build/up:?
This is an identification of your set-up in Epiqa configuration and type of images which you use for configuration:
1 – raw images (without Varian portal dosimetry), no build up
2 – raw images, d max
3 – raw images, mix
4 – CU calibrated images, no build up
5 – CU calibrated images, d max
6 – CU calibrated images, mix
12 – FFF images, mix

Q: I forgot to acquire the 10×10 field with the verification plan, can I use 10×10 field acquired earlier?
It is important to irradiate 10×10 field in the same session with your verification plan. Epiqa need 10×10 field to check the position of the portal vision and daily output of machine, because you verify absolute dose. So we suggest you to irradiate verification plan once more and in the same session 10×10 field, 50 MU. Then evaluate new PV images in Epiqa.

Q: When we compared our results from Epiqa and from Varian Portal Dosimetry we found some discrepancies.
Your result with Varian portal dosimetry can be different, because for the calculation of the reference images in Varian portal dosimetry you use PDIP algorithm (you get predicted image), but it isn´t the same algorithm as you use for patient plan calculation. For patient you use AAA (PBC) and in Epiqa you can verify this calculation with AAA (PBC).
See Epiqa user experience on: Comparing Epiqa and Varian Portal Dosimetry

Last update on 22. July 2020