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QA & Dosimetry Symposium Speaker Spotlight: Vikren Sarkar, Ph.D.

February 16, 2016

Vikren Sarkar, Ph.D.

As TG-101 suggests, and as anyone who does SRS knows, there are multiple steps between simulating a patient and finally delivering a stereotactic treatment.

Because of the interdependencies of these steps, end-to-end testing is crucial in order to identify and quantify dose discrepancies between what is prescribed and what is delivered.

Like several other institutions and facilities, we used to have a jerry-rigged end-to-end solution that went back and forth between our clinic and machine shop, enduring several slight changes in design and engineering.

Finally, as a team, we decided to look for a commercial option because we realized each iteration was costing us time and money. Moreover, we would have more confidence that our phantom was expertly-designed, precisely-milled and quality-assured by professionals.

Our options were the Lucy® phantom, which has long been commercially available, and therefore accepted by the market, or the relatively new StereoPHAN™ phantom from Sun Nuclear. One main question was, "should I even trust the 'new kid on the block,' or not?"

I designed several tests across the end-to-end SRS QA process which would allow head-to-head comparisons of the phantoms. My QADS presentations will reveal what I found.

Some may think the presentation will skew in favor of the Sun Nuclear phantom because they are hosting the symposium. But I think the audience will find the tests were designed to pit the phantoms against stringent clinical requirements, rather than promoting a specific brand. The stakes are way too high for anything less.

In a given week, we have roughly 10 patients receiving stereotactic treatments. During set up, you can often tell the patients are fearful, and may have questions about what is going on. It's important to be able to confidently answer their questions, and assure them that because we have taken the highest care in preparing their treatment, they are in good hands.

Part of that confidence comes from ensuring our end-to-end QA tools can reliably deliver accurate and repeatable results.

It's with this mindset that I started this comparison project.

I hope the audience walks away with a good understanding of which phantom works best for their clinical needs. I also hope my talk sparks some thought about how much the industry would benefit from standardizing high quality in the production of stereotactic QA tools.

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