Medical
Physics

We look forward to receiving and sharing your anonymized patient cases to be discussed with an extended network of experts in the field of SRS & SBRT.

122 Ramat Yam St, Herzliya, Tel Aviv District, Israel

Dear Doctors,


My region customers are looking for patient specific  small field VMAT dosimetry tools compatible with cranial SRS 3.0& Multiple Brainmets 3.0.


Could you recommend small field VMAT dosimetry tools models to us.


This may be helpful to new customers.


Regards,


Balasubramanian




This is Ganesh, medical physicist at Univ of Arkansas for Medical Sciences and I attended Dr Agazaryan's talk on Brainlab at the AAPM annual convention. I have a follow up question on the topic.   We have been using Brainlab MME ver 2.0 with Exactrac localization for little less than an year now. Our physicians define the tumor contours (GTV) for multiple mets on CT after fusing with MR. When it comes to defining the target (CTV or PTV) using a treatment margin, I would need an overall treatment error for a single-iso multi-mets plan and a single cranial tumor plan. We use single iso and multiple non-coplanar arcs in Truebeam sTx and planning is done on Brainlab MME ver 2.0. Our suggestion had been 0.5 mm margin for any target within 5 cm from txt Isocenter and 1 mm beyond that. I would like to double-check these margins with what is used at other institutions. ​It would be great if you can share your thoughts. We wont necessarily use it per se, but would like to have a good comparison point.


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Added a Expert Question to , Medical Physics

Hello,

I'm looking for Normal Whole Brain Volume Dose Tolerance for single fraction SRS Brain plans. We have historically used V(1200cGy) < 10cc but with people using single isocenters to treat multiple mets it's becoming easier to treat more mets than before. I would assume we are able to push the "limit" of the historic normal whole brain tolerance but there isn't much literature with regards to this. If you do use a larger tolerance than above, please share and include literature references if there are any. Thank you.

 

Rich


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Added a Expert Question to , Medical Physics

We have been using IR markers for Lung SBRT for several years and have been able to use them without too many problems. We recently upgraded to Exactrac V 6.2.2 from 6.2.1. We have noticed that we have not been able to use the IR markers to position the patient since then. When we set up a patient with IR markers, the Exactrac system is not able to move to the initial isocenter and finalize position. It keeps trying and then will say position not reached. We have not had this issue before consistently. We are not sure if this is an issue with our upgrade or potentially with the IR camera. What we have been able to narrow down is that the system works fine on a phantom setup where there is no movement. It is not able to move to position with patients now, even though the patient has minimal movement. Has anyone run into a similar issue? Any help is appreciated. Thank you.


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Added a Expert Question to , Medical Physics

We have been using IR markers for Lung SBRT for several years and have been able to use them without too many problems. We recently upgraded to Exactrac V 6.2.2 from 6.2.1. We have noticed that we have not been able to use the IR markers to position the patient since then. When we set up a patient with IR markers, the Exactrac system is not able to move to the initial isocenter and finalize position. It keeps trying and then will say position not reached. We have not had this issue before consistently. We are not sure if this is an issue with our upgrade or potentially with the IR camera. What we have been able to narrow down is that the system works fine on a phantom setup where there is no movement. It is not able to move to position with patients now, even though the patient has minimal movement. Has anyone run into a similar issue? Any help is appreciated. Thank you.