Zap-X and SRS

[SBRTreble]

I know it was discussed a while back, but it has been a while and I wonder if anyone has had recent experience using Zap-X for brain radiosurgery. Specifically, are people treating more than 2-3 brain mets, and how is the quality of the treatment planning? Would appreciate any thoughts/feedback!

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[NotMattSpraker]

I have limited experience. Covered some treatments but not a central part of that team.

Physicists seem to not like the treatment planning compared to Linac SRS. We were treating multiple brain mets, but I cant remember a case of >3 or 4? Multi target the team prefers Linac, same for small target/high dose ex. Trigem.

If you showed me linac SRS versus ZapX dosimetry for a relatively simple plan, Im not sure I could tell the difference. It did good plans. The limited angles on the ZapX seemed to be the main point of contention.

I find the interface and delivery process to be clunky. It seems kinda scary to be in it, its like a coffin. I enjoy treating in a room with windows though.

 

[Palex80]

We were treating multiple brain mets, but I cant remember a case of >3 or 4? Multi target the team prefers Linac, same for small target/high dose ex. Trigem.

Is it because the machine cannot treat several targets with one common isocenter?

 

[TheWallnerus]

If you want a vaultless SRS, there has to be some tradeoffs I guess. A new vault will cost around $1.5m these days.

 

[Neuronix]

I know it was discussed a while back, but it has been a while and I wonder if anyone has had recent experience using Zap-X for brain radiosurgery. Specifically, are people treating more than 2-3 brain mets, and how is the quality of the treatment planning? Would appreciate any thoughts/feedback!

I've evaluated a number of plans and they look like hot garbage compared to MLC based systems or any recent GK system that uses mixed shots/blocking.

Other than that they're cheap, don't require shielding, and some "newness" factor, I have no idea why anyone would buy one. If you want to do brain radiosurgery only, buy a GK or some microMLC based thing (Novalis/BrainLab). If you want to do stereotactic therapy anywhere, buy a CK. If you want the rad onc equivalent of a swiss army knife, buy an Edge.

Is it because the machine cannot treat several targets with one common isocenter?

Correct me if I'm wrong, but it's cone (iris system?) based, not MLC. I feel like we're going backwards in technology.

 

[SBRTreble]

ok, good to know - I appreciate it!

The primary motivation is running out of space, and the 'vaultlessness' of it all is the main attraction. Just trying to figure out how much we'd lose in terms of quality and sophistication compared to our Truebeam. Sounds like it could be substantial. Thanks

 

[medgator]

If you want a vaultless SRS, there has to be some tradeoffs I guess. A new vault will cost around $1.5m these days.

And Medicare took out the vault expense years ago in it's reimbursement calculation models iirc

 

[seper]

no vault, no cobalt? that’d be nice

 

[Gfunk6]

As I understand it, ZAP was designed with primarily the Asian (Chinese) market in mind by Adler. They have a very large population with a lot of cancers, statistically speaking. It would be nice to have a machine that is capable of intracranial SRS which is relatively cheap and doesn't require a vault.