A new (wrong) behavior with MLC (Pinnacle 8 to 9 )

[Tercier Pierre-Alain]

Dears,

The title says everything.

If you are a DMPO regular user/fan pay attention...

We are using DMPO IMRT with Varian machine.
With Pinnacle 8.0m nothing to say (it was +/- perfect).
Starting from Pinnacle 8.0m we take the machine and re-commisionned them
to go with Pinnacle 9.0b.

And we see that the new variable called "Minimum dynamic leaf gap (cm) :" in the
"MLC Editor window" (Physics tool) interferes with DMPO (which is static!?!?).
It was setup at 0.05 cm (coming from Pinnacle 8.0m).

If you change an MLC position manually (to help the DMPO algorithm) and restart
the optimisation. You see "closed" leaves are assigned with a 0.05 cm gap.
You cannot close the leaves completely. And DMPO let also this new gap during
the optimisation (it doesn't create it but it doesn't remove it also).

We change the 0.05 cm gap "Minimum dynamic leaf gap (cm) :" to 0.00 cm.
In the "Physics tool" and recommission the machine.

The wrong behavior disappears (the closed leaves are really closed).
And can also be manually closed at 0.00 cm gap which was no more possible
before.

So as we do not use "sliding windows" we let the wrong 0.00 cm gap for the
"Minimum dynamic leaf gap (cm) :" parameter (from Varian doc it should be at
0.05 cm).

The DMPO treatment are ok again with our QA and so on.

I hope to see somebody from Philips stand up to clean the BUG.
Because it's clearly a new BUG. Manual moves in the MLC position
introduces gap in a DMPO treatment which stay to the end of
optimisation (at least if you are unlucky).

At the moment do not touch manually the MLC or change the dynamic gap to 0.00 cm
for DMPO. For department with "sliding windows" and DMPO treatments I have no
counter measure in mind. Sorry!

Thanks
Pat

--
Dr. es Sciences, Phys. Méd. SSRPM
TERCIER Pierre-Alain
Service de Radio-oncologie tel: +41 26 4267681
HFR - Hôpital Cantonal fax: +41 26 4267665
CH-1708 Fribourg

[Andrew Jones]

We noticed this as well.  But, there truly is a 0.05 cm gap in the Varian leaves when closed so this does appear to model the MLC correctly.  Perhaps I'm overlooking a detail here?

 

AJ

 

 

Andrew O. Jones, PhD
Director, Radiation Physics Group
Department of Radiation Oncology
Geisinger Medical Center
N. Academy Ave
Danville, PA  17822
570 271-6304


>>> "Tercier Pierre-Alain" <pinnacle3-users+bncCLT...@googlegroups.com> 10/20/2010 4:56 AM >>>

--
You received this message because you are subscribed to the Google
Groups "pinnacle3-users" group.
To post to this group, send email to pinnacl...@googlegroups.com
To subscribe to this group, send email to
pinnacle3-us...@googlegroups.com
To unsubscribe from this group, send email to
pinnacle3-use...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/pinnacle3-users?hl=en

---

IMPORTANT WARNING: The information in this message (and the documents attached to it, if any) is confidential and may be legally privileged. It is intended solely for the addressee. Access to this message by anyone else is unauthorized. If you are not the intended recipient, any disclosure, copying, distribution or any action taken, or omitted to be taken, in reliance on it is prohibited and may be unlawful. If you have received this message in error, please delete all electronic copies of this message (and the documents attached to it, if any), destroy any hard copies you may have created and notify me immediately by replying to this email. Thank you.

[Bert Goudry]

Hello,

After a small discussion at our department I have a question about what you wrote: “If you change an MLC position manually (to help the DMPO algorithm)”.  

What do you mean by this? Why do you change mlc positions when optimizing a IMRT-plan?

Bert

____________________________________________________________________________

Bert Goudry

Dosimetrist

Universitaire Radiotherapie Antwerpen
ZNA Middelheim
Lindendreef 1
2020 Antwerpen
Belgium

 

+32 3 2802188

bert.goudry@zna.be

____________________________________________________________________________

 

---

Dr. es Sciences, Phys. Md. SSRPM

TERCIER Pierre-Alain
Service de Radio-oncologie             tel: +41 26 4267681

HFR - Hpital Cantonal                 fax: +41 26 4267665

CH-1708 Fribourg


--
You received this message because you are subscribed to the Google
Groups "pinnacle3-users" group.
To post to this group, send email to pinnacl...@googlegroups.com
To subscribe to this group, send email to
pinnacle3-us...@googlegroups.com
To unsubscribe from this group, send email to
pinnacle3-use...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/pinnacle3-users?hl=en

[Feygelman, Vladimir]

Not to mention that under normal circumstances the leaves are closed under the jaw, so this does not matter at all.

 

VF

 

---

Dr. es Sciences, Phys. Md. SSRPM

TERCIER Pierre-Alain
Service de Radio-oncologie             tel: +41 26 4267681

HFR - Hpital Cantonal                 fax: +41 26 4267665

CH-1708 Fribourg


--
You received this message because you are subscribed to the Google
Groups "pinnacle3-users" group.
To post to this group, send email to pinnacl...@googlegroups.com
To subscribe to this group, send email to
pinnacle3-us...@googlegroups.com
To unsubscribe from this group, send email to
pinnacle3-use...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/pinnacle3-users?hl=en

---

IMPORTANT WARNING: The information in this message (and the documents attached to it, if any) is confidential and may be legally privileged. It is intended solely for the addressee. Access to this message by anyone else is unauthorized. If you are not the intended recipient, any disclosure, copying, distribution or any action taken, or omitted to be taken, in reliance on it is prohibited and may be unlawful. If you have received this message in error, please delete all electronic copies of this message (and the documents attached to it, if any), destroy any hard copies you may have created and notify me immediately by replying to this email. Thank you.

--
You received this message because you are subscribed to the Google
Groups "pinnacle3-users" group.
To post to this group, send email to pinnacl...@googlegroups.com
To subscribe to this group, send email to
pinnacle3-us...@googlegroups.com
To unsubscribe from this group, send email to
pinnacle3-use...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/pinnacle3-users?hl=en

This transmission may be confidential or protected from disclosure and is only for review and use by the intended recipient. Access by anyone else is unauthorized. Any unauthorized reader is hereby notified that any review, use, dissemination, disclosure or copying of this information, or any act or omission taken in reliance on it, is prohibited and may be unlawful. If you received this transmission in error, please notify the sender immediately. Thank you.

[Tercier Pierre-Alain]

No, No, you are beside the target, sorry,

 

Definitely not it's wrong we have no gap in the leaves in Pinnacle under the jaws (the gap is 0.00cm).

 

In ARIA (we also have Eclipse) the gap is 0.00 cm everyplaces where you want to have it 0.00.

 

In Pinnacle 8.0 it's the same as Eclipse (that is good IMHO).

 

In Pinnacle 9.0 if you are not covered by jaws you cannot put 0.00cm gap

(if you let the dynamic gap at 0.05 cm according to Varian doc).

 

In Pinnacle 9.0 it's the same as Eclipse (that is good IMHO).

(if you corrupt the dynamic gap to 0.00 cm dis-according to Varian doc).

This will be ok if you do not use sliding windows. But otherwise ???

 

How to say more!

 

Sad day

Pat

 

--
Dr. es Sciences, Phys. Méd. SSRPM
TERCIER Pierre-Alain
Service de Radio-oncologie             tel: +41 26 4267681
HFR - Hôpital Cantonal                 fax: +41 26 4267665
CH-1708 Fribourg

 

---

De : pinnacl...@googlegroups.com [mailto:pinnacl...@googlegroups.com] De la part de Andrew Jones
Envoyé : mercredi, 20. octobre 2010 13:54
À : pinnacl...@googlegroups.com
Objet : Re: [p3rtp] A new (wrong) behavior with MLC (Pinnacle 8 to 9 )

Dr. es Sciences, Phys. Md. SSRPM

TERCIER Pierre-Alain
Service de Radio-oncologie             tel: +41 26 4267681

HFR - Hpital Cantonal                 fax: +41 26 4267665

CH-1708 Fribourg


--
You received this message because you are subscribed to the Google
Groups "pinnacle3-users" group.
To post to this group, send email to pinnacl...@googlegroups.com
To subscribe to this group, send email to
pinnacle3-us...@googlegroups.com
To unsubscribe from this group, send email to
pinnacle3-use...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/pinnacle3-users?hl=en

[Tercier Pierre-Alain]

It's not the problem but I can explain it to you.

 

Pre-caution (we have min 4 MU and 4 cm2)

 

In some circumstances during DMPO some small places blocked to a 3.9999 MU and small area.

It happen that we see a place where the dose is missing. So we close the MLC (leaves by leaves)

at the places where the MLC was open and repopen at the place where we identify the

missing dose. A re-start of optimisation and it's ok...

 

We see (not everytime to be honnest) an improvement in the cost function and on isodoses.

 

You may not ignore that the DMPO algorithm is not convex. Therefore it's not a big

surprise that it could be trapped in a local minimum. I guess our "manual" moves of

leaves push the conditions in another place where the algo reaches a better

solution.

 

That's it (and for some of these cases we see the problem with MLC (Pinnacle 9 and never

with Pinnacle 8).

 

Pffiuww

Thanks to everybody

Bye

Pat

 

--
Dr. es Sciences, Phys. Méd. SSRPM

TERCIER Pierre-Alain
Service de Radio-oncologie             tel: +41 26 4267681

HFR - Hôpital Cantonal                 fax: +41 26 4267665
CH-1708 Fribourg

 

---

De : pinnacl...@googlegroups.com [mailto:pinnacl...@googlegroups.com] De la part de Bert Goudry
Envoyé : mercredi, 20. octobre 2010 14:58
À : pinnacl...@googlegroups.com
Objet : RE: [p3rtp] A new (wrong) behavior with MLC (Pinnacle 8 to 9 )

[grégory bolard]

Hello Pierre-Alain,

You're right. It's definitively a problem. If you edit manually the leaf positions before a second optimization,
the dynamic leaf gap is added between closed leaves for a step and shoot plan.
Thanks for this information. For people using also dynamic mlc delivery (Dynamic Arc or Sliding Window) a solution
can be to temporary set the dynamic leaf gap value to 0 by a script for a DMPO optimization (MachineList.Current.MultiLeaf.MinDynLeafGap=0;).

Another thing:
We encounter a problem with the computation of a list of planar dose in v9. The dose is cancelled automatically
for all planar doses each time Pinnacle calculate a new dose map. Are we alone to have this problem?

Greg
Clinique de Genolier
Switzerland

> Message du 21/10/10 08:59
> De : "Tercier Pierre-Alain"
> A : pinnacl...@googlegroups.com
> Copie à :
> Objet : RE: [p3rtp] A new (wrong) behavior with MLC (Pinnacle 8 to 9 )
>
> IMPORTANT WARNING

> >>> "Tercier Pierre-Alain" 10/20/2010 4:56 AM >>>

[Tercier Pierre-Alain]

Dear Greg,

 

No we also see this problem!

 

Now a way to see it disappear is:

 

1) Put a dose grid at a correct place

2) Calculate all the beams (Compute / spread)

3) Pay attention to point for your prescription to a point where it make sense (even if DMPO will

prescribe by MU). You have to define a point dose then choose again prescription by MU.

4) Calculate PlanarDose (and "spread" works).

 

I don't know why but up to now it solves all this "bizarre" behavior where it calculates a planard

dose and cancel it as soon as it goes to the next one.

 

Bye

Pat

--
Dr. es Sciences, Phys. Méd. SSRPM
TERCIER Pierre-Alain
Service de Radio-oncologie             tel: +41 26 4267681
HFR - Hôpital Cantonal                 fax: +41 26 4267665
CH-1708 Fribourg

 

---

De : pinnacl...@googlegroups.com [mailto:pinnacl...@googlegroups.com] De la part de grégory bolard
Envoyé : jeudi, 21. octobre 2010 09:35
À : pinnacl...@googlegroups.com