Team Goshen: Making Good in "The Maple City" 

By Benjamin E. Nelms
Originally published in the Fall/Winter 2007 issue of  the.decimal point

The “Technology Demographics” of Solid IMRT

The population of Solid IMRT users is strong and ever-growing. As of September, 2007, there were a total of 174 .decimal customers. In the month of August, 2007, .decimal received orders for IMRT modulators from 117 unique radiation therapy centers. As this population grows, the demographic profiles of the user base become clearer. Of great interest are the “technology demographics” – the breakdowns of the different technologies which are used at .decimal customer sites (treatment planning, linear accelerators, IGRT quality assurance, etc.).

On the delivery side, the demographic seems to be clumping into three major sub-populations. The first, and most obvious, subpopulation is comprised of sites that have modern linear accelerators that are not equipped with MLC.

For these sites, .decimal brings their perfectly good high-energy photon machine(s) up to state-of-the-art IMRT delivery capability without requiring the huge up-front capital investment. The second major subpopulation consists of sites that have MLC and are capable of MLCbased IMRT but choose to use Solid IMRT instead. This choice is made for any number of reasons, with one common reason being the time  inefficiency of certain segmented MLC deliveries, a problem that leads to longer delivery time, longer fraction time slots, and added discomfort for the patients. The third major sub-population of Solid IMRT users is quite interesting but very expected – the sites that are experienced and effective practitioners of MLC-based IMRT, but that choose to have .decimal “in their toolbox” for special cases where Solid IMRT presents obvious clinical and practical benefits.

The Center for Cancer Care  in Goshen, Indiana is a textbook case of the third sub-population in the Solid IMRT technology demographic. The first sentence in this center’s mission statement is,  “Our mission is to provide the best cancer care available to our patients and their families.” One visit with the clinicians at Goshen’s Center for Cancer Care and you will realize that, in wonderful ways, this center takes this statement seriously and literally. It is not relegated to be some generic, feel-good statement for the web page. Truly, and simply, this does seem to be their mission.

Welcome to Goshen, Indiana
“The Land of Goshen” in ancient texts is hallowed ground, located around the delta of the Nile River in northern Egypt. If you were to draw an isosceles triangle with Mt. Sinai as the south point and the city of Jerusalem in the northeast, you’d trace out that the northwest corner would be smack dab in the middle of the Land of Goshen.

Well, you don’t have to go so far to find “the other Goshen” right here in the USA. “The Maple City” (as it is known to those familiar) is at the northern, central edge of Indiana, near the Michigan border in an area often colloquially called “Michiana.”

It is about 100 miles east of Chicago and about a marathon run east from South Bend. Originally settled by the Amish and Mennonites circa 1831,the friendliness and hard-working, honest-living character seems to be deeply engrained in the DNA of the town. It’s quintessential Middle America. You’ll find a Dunkin’ Donuts and fervor for local high school sports just like any humble city of 30,000 or so people.

Goshen will surprise you, though. Driving into Goshen, little will you know that Elkhart County is somewhat rich in entrepreneurial history, such as being a boom-town of the recreational vehicle (better known as “RV”) industry. A lot of the fine folks of the area have re-invested in their community through a dedication to offer the finest medical care available. Which brings us back to Goshen’s Center for Cancer Care…

The Center for Cancer Care and Team Goshen
As mentioned earlier, Goshen’s cancer center has an impressive technological profile to back up their mission to provide “the best cancer care available.” In the radiation therapy department, they have a Varian 2100 EX with 120-leaf MLC, a Tomotherapy Hi-Art machine, and a new Varian Trilogy on the way.

They use the latest and greatest Varian Eclipse treatment planning software, often incorporating multimodality imaging to more accurately delineate target volumes (and are also planning for a dedicated PET/CT device soon). IGRT is the norm, with daily localization via tomotherapy CT, ultrasound, or portal imaging. They are also experts in HDR brachytherapy and mammosite treatments. But as we all know, a football team with the neatest jerseys, an immaculate home field turf, and the cleanest bleachers does not automatically make them the state champs. It takes players. And Goshen’s Center for Cancer Care has good players, so to speak. Really good players. As a case in point, I’ll recount an experience I had at a regional Solid IMRT users’ meeting this summer in South Bend, Indiana. The meeting was very well-attended, and the talks very valuable, practical, and in all sincerity, pretty darn interesting.

On the morning of the first day was a talk by somebody I had never met, Dr. James Wheeler.  Perhaps I was charging up my coffee or something during the speaker introduction, and as a result I was not quite sure of Dr. Wheeler’s position or background.

A few minutes into the talk, I was already thinking to myself: “Cool. This is a physicist who really knows his stuff.” A few more minutesinto the talk and I had added to my subconscious impression: “Wow. He’s hitting scientific and analytical thinking in perfect stride.” Then came the kicker a few minutes later, when it became apparent that Dr. Wheeler was not Dr. Wheeler, Medical Physicist, but rather Dr. Wheeler, Radiation Oncologist. As it turns out, Dr. Wheeler is the Director of the radiation oncology program at Goshen, and M.D./Ph.D. with a doctoral degree in Physical Chemistry. Dr. Wheeler’s command over the challenges and solutions of radiation oncology is matched by the rest of the staff, or “Team Goshen” as I’ll call them here. The physics staff has aces like John Lowden and Brent Murphy (who also founded Advanced Radiation Consulting and Infinite Planning Solutions, which offer nationwide hands-on training courses in clinical medical physics), a fine-tuned IMRT/dosimetry staff, and a crew of therapists who have mastered the process of perfraction IGRT. The quality and experience goes all the way to the top, to Medical Director Douglas J. Schwartzentruber (MD, FACS) whose accomplishments include being the Senior Investigator of the surgery branch of the National Cancer Institute (NCI) for 13 years.

Given this staff and equipment profile, it goes without saying that .decimal, Inc. was very happy to have their product selected to join Team Goshen, a decision the staff at Goshen made about a year ago (late 2006). Goshen finished commissioning of Solid IMRT rapidly, in December of 2006. Earlier that year they had commissioned their Tomotherapy system (July 2006) and five years before that they had commissioned MLC-based IMRT (2001).

Team Goshen’s Early Experiences with Solid IMRT
Although they have less than a year with Solid IMRT under their belt, Team Goshen seems to have joined the list of seasoned veterans,rich in experience and opinions. A common question by those learning about Solid IMRT is whether it complicates workflow of treatment planning or actual delivery (with the therapist having to walk into the treatment room to load the custom modulator for each beam).

Regarding treatment planning, John Lowden (who has experience with Solid IMRT with XiO, Pinnacle3, and Eclipse) responded to this question with an emphatic “No” and even added, “The amount of trials (iterations) that have to be run to match the optimized fluence are considerably less. The compensators are the optimal fluence.” He added that with Pinnacle and XiO, the planning for Solid IMRT is easier (vs. MLC-based) and for Eclipse about the same, the only difference being that with Eclipse the beam weights must be re-entered by hand after the DICOM RT Plan (from the .decimal program “p.d”) is reimported back into Eclipse.

As for the workflow of the daily fractions and the therapist in-and out of the room with each beam, Lowden recounted something important, “A benefit that has been lost with the addition of recent technology (MLC, Tomo) is the therapists’ recurring checks of patient positioning during the treatment. If the therapists no longer go in the room between treatment fields, patients are not being doublechecked to see if they are remaining on their (positioning) marks.” (Note: This thought was echoed by Dave Vassy, Chief Medical Physicist in Spartanburg, SC, at the recent Solid IMRT Conference in South Bend. Dave also finds the in-and-out of the therapist required by Solid IMRT is of great practical benefit in verifying the patient’s position remain correct during the fraction.) Also regarding delivery efficiency, Lowden claims that Solid IMRT is often preferred due to its efficiency advantages over other techniques. “Solid IMRT has decreased the treatment time in treating head and neck patients. We have a Varian 2100 EX which ‘splits fields’ if the field size is greater than 14 cm in width, which is almost always the case with head and neck patients. Our 7-field beam arrangement would turn into 14 treatment fields. This increased our treatment times from 15 min to 25 min. Solid IMRT does not have this problem, and it also decreases the total monitor units delivered by about a factor of 3.”

On my first visit to Goshen, they had just received a shipment of .decimal brass modulators for a complex (and large volume) lung treatment. In fact, Solid IMRT has become the treatment of choice for radiation delivery to the lung at Goshen, based on the limited dose degradation of a temporally static modulation vs. the temporally dynamic modulation techniques (such as Tomotherapy or MLC). Dr. Wheeler elaborates: “With solid tissue compensators, we do not have to worry about geographic miss due to respiratory motion. It’s much easier to use solid tissue compensators than to incorporate all the complexities of full respiratory gating. We are now using solid tissue compensators for all of our lung cancer patients and our patients who have distal esophageal cancer, where tumor motion could also be an issue.”

Asked about whether his colleagues in the industry are catching on to the advantages of Solid IMRT in cases of organ motion, Dr. Wheeler replied: “It is likely to take a few more years before clinicians fully appreciate the importance of organ motion.

As more and more systems develop 4-D treatment planning software, the simplicity of using solid tissue compensators will become more apparent. Even centers with sophisticated respiratory gating technologies can still use solid tissue compensation to limit the larget volumes without having to ever worry about the leaves from the multileaf collimators being closed at the time the tumor is in a particular location.”

The set of brass modulators I saw on my visit was impressive, but I had to note that each was fairly large (due to the large fields) and could potentially be cumbersome if a therapist was diminutive. I asked Lowden about this. He responded, “The weight of the compensators for small fields is negligible, but with large lung fields the weight can be as high as 20 lbs. This is difficult for some therapists and they need assistance, which slows the process down.”

But as I handled and admired one of the heavy lung modulators, a therapist (and a diminutive one at that) walked in the room. I asked her if she thought the weight of large modulators was ever a problem. She rolled her eyes, acknowledging the question but assuring me it was nothing she couldn’t handle.

Such is the way of Team Goshen – top notch, and up to the challenge.