VMAT: Rapidarc vs. Tomotherapy

[medgator]

Advertisement - Members don't see this ad

Just wanted to start a thread on helical IMRT/tomotherapy and rapidarc/VMAT (Volumetric Modulated Arc Therapy)

What do you guys think about varian's answer to helical tomotherapy, namely rapidarc? Elekta also has a VMAT solution apparently.

I had quickly skimmed an article in some physics journal (came out a month or two ago) comparing the two, and it seemed like a mixed bag: Rapid arc can certainly deliver IMRT faster, but I get the sense that tomotherapy can provide a better plan. Apparently tomotherapy sponsored a contest to challenge someone to provide a better plan using a different system, and it seems that no one has taken them up on it. Rapidarc seems well-suited to better throughput (i.e. getting 30+ IMRT patients treated per day).

 

[Palex80]

RapidArc and VMAT (Elekta also has VMAT coming out) are extremely handy techniques to deliver a high patient output on one LINAC. Indeed one can treat a lot more patients with these techniques, than with standard IMRT, because they are a lot faster. This can be extremely handy in the case of Head+Neck or Pelvis RT.
On the other hand, these techniques are not as good as Tomotherapy, when it comes to delivering THE perfect plan for the patient.

I would say that RapidArc/VMAT are excellent techniques for standard IMRT procedures on a daily basis. A clinic that has these features can become a lot more lucrative than before, because more patients can be treated per LINAC. But when it comes to very special cases, difficult tumour localizations or large volume treatment, I would still want to have Tomotherapy available. There are some indications, for which Tomotherapy is simply unbeatable IMHO, like whole abdominal RT (emerging studies for OvarialCa) or bone marrow directed TBI.

The problems with Tomotherapy are the costs (it's quite expensive), the fact that you need the whole infrastructure just for one machine (planning system, server, etc) and that you can't treat a ot of patients / day continuisly without expecting a major breakdown. I have witnessed a Tomotherapy machine breaking down after patient load was increased to 30 patients / day. One very important aspect is that you need a backup plan, in case your Tomotherapy machine breaks down and won't be available for 1-2 days in some cases (for example H&N). The problem is that creating a plan that quickly aint that easy, since the Tomotherapy planning system is a stand-alone solution.

 

[medgator]

The problem is that creating a plan that quickly aint that easy, since the Tomotherapy planning system is a stand-alone solution.

I've heard that tomo is working on something to interface with Varian ARIA/eclipse, to allow for that.