Download a PDF of the Current Issue 2015 Volume 12 Number 3 July- September

University of Florida Proton Therapy Institute: A Unique Cancer Treatment and Research Center

Gary Barlow, BSRT, Director for Technical Services Theresa Edwards Makrush
8-3-3 The largest medical device in use today deploys one of the smallest particles known to man to effectively treat cancer patients. The device is a particle accelerator. The particle is the positively charged part of an atom called a proton. The cancer treatment is proton therapy.   There are fewer than 30 of these devices worldwide, nine in the U.S., one in the Southeast. It is at the University of Florida Proton Therapy Institute in Jacksonville, Fla. The 98,000-square-foot facility houses both conventional radiation therapy and proton therapy. There are four rooms for proton therapy, three that are equipped with treatment gantries that are each 30 feet in diameter and rotate 360 degrees in either direction to position the treatment nozzle. The cyclotron that generates the protons weighs 440,000 pounds and uses electromagnets to accelerate the particles to two-thirds the speed of light. Each patient is treated with a customized beam of protons, produced in the cyclotron, injected into the beam-line, transported to the gantry and through the treatment nozzle. Less than a microsecond is all it takes the proton beam to travel from start to finish, to its targeted cancer.   Proton therapy is a type of external radiotherapy. The most common form of external radiotherapy uses X-rays. X-rays are waves of energy. Upon entering a patient, X-rays may interact with tissues in their path, some are absorbed in these interactions, but most pass through the patient. When X-rays are absorbed, they release radiation energy that can destroy both cancer cells and normal, healthy cells along their path. Like a bullet, an X-ray beam leaves a path of damage as it passes through the patient. Protons are particles with mass.  Unlike X-rays, protons travel only a finite distance and release the majority of their radiation energy just before stopping. How far they travel is related to their acceleration—the greater the acceleration, the deeper they penetrate into the body.  In contrast to X-rays, protons lose only a little energy, or radiation dose, in normal tissues on the way to the target and they release most of their energy, or radiation dose just before stopping. The protons can be accelerated to stop in the cancer.  Because the protons stop in the targeted cancer, no radiation energy is released beyond the cancer, as with X-rays. In this way, protons deliver relatively more of their radiation energy to the cancer than X-rays and much less radiation to normal tissues, thereby causing less damage to normal, healthy cells. In the sense that protons deposit relatively more of their radiation energy in the target than X-rays, protons are more accurate and more efficient than X-rays.   Proton therapy enables the radiation oncologists to deliver high doses of radiation to the targeted cancer without exposing as much normal tissue to radiation as necessary with X-rays. Protons are therefore ideal for treating cancers located in or near critical organs like the brain, head and neck, eye, lung, pancreas and prostate.   The UF Proton Therapy Institute is affiliated with the UF College of Medicine’s Department of Radiation Oncology and the UF Shands Cancer Center. It is a not-for-profit, 501(c) 3, cancer treatment and research facility. The project was initiated in 1998 when then department chair Dr. Nancy P. Mendenhall identified proton therapy as the future of radiation oncology. Following a five-year feasibility study, facility construction began in 2003 and was completed in 2006 with the first proton therapy patient treated on August 14, 2006. With Dr. Mendenhall now serving as medical director of UF Proton Therapy Institute, the facility is fulfilling its mission: to bring cancer patients the best chance for cure with the least risk of complications and to generate scientific evidence for the optimal uses of proton therapy in cancer treatment.   Because there are currently only nine proton therapy facilities in the country, protons are a rare medical resource and the UF Proton Therapy Institute is committed to making this promising technology available to as many patients as possible. With a focus on accuracy and efficiency, approximately 94,000 treatments have been delivered to more than 2,700 patients since August 2006. The types of cancers treated include head and neck, brain, lung, central nervous system, soft tissue (sarcoma), lymphoma, pancreas and prostate as well as cancers in children. Proton therapy is particularly beneficial for treating cancer in children whose rapidly growing bodies are more susceptible to the harmful effects of radiation. Recent studies from St. Jude Children’s Research Hospital show that even small amounts of radiation exposure in children cause permanent damage to IQ, hinder the body’s normal growth and development and increase risk for secondary cancers later in life. The pediatric program at UF Proton Therapy Institute has become one of the busiest in the country, treating 15 to 20 pediatric patients each day. Thus far, more than 200 children have received proton therapy at the facility.   Patients come from near and far to have proton therapy. About 70 percent of patients come from beyond a 60 mile radius and include people from 49 states and more than a dozen countries such as Great Britain, Norway, Saudi Arabia, Pakistan, Peru, Nicaragua and Hong Kong. On average, 110 patients are treated each day Monday through Friday from 6:30 a.m. until 10 p.m. Each patient receives daily proton therapy for six to eight-weeks. An active patient services program provides patients with opportunities to get to know each other, share their common treatment experiences and socialize. This social network creates a community for patients, many of whom are far from their traditional support system of family and friends.   As an academic medical treatment and research facility, the radiation oncologists and physicists at UF Proton Therapy Institute are UF faculty. The facility is one of the first clinically dedicated proton therapy centers in the world. Nearly 98 percent of all patients at the institute are on one or more protocols and clinical trials. Important areas of study include prostate cancer and pediatric cancers, Hodgkin’s lymphoma, lung and pancreas cancer, bone and soft tissue tumors in critical sites, brain tumors and cancer of the head and neck area.  Early findings in prostate cancer, lung and pancreatic cancer, Hodgkin’s lymphoma, and head and neck cancers have been presented at national and international meetings. The University of Florida Proton Therapy Institute is also collaborating with St. Jude Children’s Research Hospital in children’s’ brain tumor trials.   UF Proton Therapy Institute is a regional, national and international resource for patients without access to proton therapy centers.  Approximately 80% of patients treated are from outside the Jacksonville area, including approximately 25% who travel more than 300 miles and over 5% from overseas.   Though focused on accuracy and efficiency, the medical professionals and staff at UF Proton Therapy Institute are also dedicated to compassionate patient care. 98 percent of patients surveyed report their quality of care as excellent and would recommend it to others.   In the coming months, the UF Proton Therapy Institute will begin treatment in a new room designed especially for patients with eye tumors and other eye disorders. In addition, a new protocol will open for patients with advanced left-sided breast cancer. Treatment planning studies indicate that proton therapy in left sided breast cancer can reduce the amount of radiation received in the heart and lung while delivering the highest possible dose of radiation to the cancer.