Dr. Anil Sharma, (R) and his colleague Dr. Venkata Lingampally (L) use Delta4 Phantom+ for verification of all complex treatment (VMAT, IMRT, TomoTherapy) performed at Long Beach Memorial Medical Center.
We recently interviewed Dr. Anil Sharma, Ph.D., D.R.P., Director, Medical Physics, Clinical Professor UCI, Memorial Radiation Oncology Center in Long Beach, California, which treats all types of cancers. Our conversation covered the current QA needs and industry trends, as well as an outlook on the future. We believe Dr. Sharma’s insights will prove valuable for other clinics looking to expedite their workflow and maximize patient safety.
You were one of the first to offer IMRT and TomoTherapy. What prompted your decision to take this direction?
In 2004, we were one of the first TomoTherapy clinics in the world, and since then have been using it for all IGRT and IMRT patients. Before TomoTherapy, there was no way of delivering image guided treatments in 3D. TomoTherapy was the first machine that came with verification in 3D and treatment planning in 3D.
How did you perform QA at that time and what were your challenges?
Initially, we were performing QA using film. We would expose and develop the film then compare the distributions with the plan and what the film showed. It used to take an hour or more to do one DQA and that was only in a single plane. Ideally, you want to do volumetric QA in three dimensions. If you are doing things with film or with other systems that don’t give you a three dimensional dose verification, you need to repeat multiple times to have full confidence that your plan is right.
Your clinic was the first U.S. clinic to buy a Delta4 Phantom+. Did these QA needs lead to your purchasing decision?
Until we got Delta4 Phantom+, we didn’t have a system to achieve three dimensional verification. Now we are able to get the verification done right then and there. We don’t need to develop film or go to another system to read the film and do verification. We looked at other systems, but Delta4 Phantom+ is ideal for making DQA measurements. You can set it up with ease and since it’s fully wireless, you don’t have to worry about running the cable all the time between your measuring device and your system.
In what ways do you use Delta4 Phantom+?
We use Delta4 Phantom+ for all complex treatments such as IMRT, VMAT, and TomoTherapy. For less complex treatments, there are other ways of sufficiently performing verification. However, for complex plans which require intensity modulated treatments such as IMRT, VMAT, and TomoTherapy, we have to use an accurate and volumetric system like Delta4Phantom+.
How has Delta4 Phantom changed your workflow and what are its benefits?
Since it’s fully wireless and doesn’t use cables, we can transfer the system from the trolley to the patient’s table with ease and start taking measurements right away; then get the results when the treatment is finished for doing the QA. It speeds things up and is easy to use. Since the detectors in Delta4 Phantom+ are located where we are giving radiation, the single most important factor is that we are now making measurements right where we are actually giving the patient treatment. That gives a lot of confidence that we are making measurements right in the area that is most crucial to our planning and dose delivery to the patient.
What is a QA challenge during your workflow that you still deal with?
Even if a patient stays absolutely still on the bed, everything is mobile and moving in their body. Suppose you are treating a lung tumor and the patient is breathing. Everything is four dimensional, so time is what we will need to account for, as things start moving towards 4D planning and 4D dose verifications in a year or two.
What do you think is the next big thing in radiation oncology?
4pi dose delivery systems with a moving couch and rotating gantry allowing for radiation to be delivered from various angles and at various heights. These 4pi systems will be coming to the market within a year or two. Once they start coming in, I think verification will become more crucial for dose deliveries, so you can better target everything.
Where do you see radiation oncology, QA, verification, in 5-10 years?
It’s hard to tell, but more and more radiation therapy is going towards hypo fractionation -- trending towards giving a lesser number of fractions and more dose per fraction. It’s starting to happen now, but will require very accurate systems for planning, dose delivery, and dose verification. Hypo fractionation is probably going to take over almost all areas and all cases we currently treat conventionally.
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