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The Department of Radiation Oncology brings advanced radiation oncologic care to Arkansas. We are a rural state with a highly disproportionate elderly population that contributes to a high incidence of cancer and other catastrophic diseases related to the aging process. Our intent is to increase survival and improve quality of life for Arkansas' cancer patients through more precise treatment, which reduces morbidity and increases the rate of organ function/life preservation. With baby boomers beginning to attain the age of 60 in 2007, we can expect cancer cases to double between 2011 and 2017. The incidence of cancer is one in 12 males and one in 11 females for ages 40-59, but increases to one in three males and one in four females for ages 60-70. We can expect a growing need for comprehensive cancer care resources and research in the state well into the future.

Radiation Oncology is one of the three major treatment modalities for cancers, which also include surgery and systemic therapy. Approximately 60% of all cancer patients will require the services of Radiation Oncology at some point in their course of treatment. Of the approximately 1,334,100 new cancer cases diagnosed in the United States (estimated by the American Cancer Society for 2003), roughly 170,000 patients will die of uncontrolled local diseases without any evidence of distant metastases (spread of cancers to other part of the body). Another 160,000 patients will also die of both uncontrolled local diseases and distant metastases. However, ample clinical evidence shows that some of this latter group of patients had local failure prior to distant metastases and in fact, the distant metastases were the result of seeding from the local failure. Thus, improved local control as a result of improved local treatment delivery could save tens of thousands of lives a year. This is one of the primary goals of the Radiation Oncology Department

Intensity Modulated Radiation Therapy

Research in radiation biology over years has suggested that escalated (increased) dose to the tumor would improve the Tumor Control Probability (TCP), i.e. reduce the relapse rate. Unfortunately dose escalation it was often hindered by unacceptable complications because of the also increased dose to surrounding critical structures. In Intensity-Modulated Radiation Therapy (IMRT), each conven¬tional wide beam is divided into a large number of beamlets with individually adjusted weights by powerful planning computer. It tailors the high-dose volume precisely around the tumor to allow the radiation oncologist to more safely escalate the radiation dose to tumors, thus potentially improving local control, and to more conformally avoid critical and radiosensitive structures, thus minimizing complications. Some patients simply cannot be safely and adequately treated without using IMRT. Therefore, the introduction of IMRT to the Arkansas population is the first critical steps in trying to improve the population health statistics.

Helical Tomotherapy

Helical Tomotherapy (Highly Integrated and Adaptive Radiotherapy - HiART System) is an evolutionary concept that takes IMRT to the next level. It not only provides the means to deliver IMRT treatments but also to perform real-time imaging and treatment analysis. That will enable us, for the first time in the history of radiotherapy, to quantify exactly where the treatment was delivered using dose reconstruction and superimposition to the patient's anatomy at the time of treatment delivery. Such information also allows adaptive radiotherapy, which is not available in IMRT delivered by any other technology. The Radiation Oncology Department at UAMS is participating as a Center of Excellence by serving as a beta site for the HiART technology in association with the University of Wisconsin and nine other centers in North America. Helical tomotherapy treatment is available at UAMS starting January 2004.

The concept of Adaptive Radiotherapy can be implemented for the first time with the HiART system. Adaptive radiotherapy is a revolutionary new concept in radiotherapy where individual patient data is collected, before and during treatment, and used to individualize the patient's treatment. The obtained data is fed back to the treatment planning computer and a new modified plan is obtained based on changes recorded during the treatment. The patient can then be treated using this modified and most up-to-date plan.

Standard radiotherapy addresses the problems of set-up and tumor motion errors by adding adequate safety margins around the target to ensure full daily dose delivery. X-ray images taken immediately prior to treatment can help verify the position of bony anatomy. Targets are secondarily related to relevant bony anatomy.

The HiART system provides the ability to obtain megavoltage CT images (MVCT) at anytime during the course of treatment. The MVCT images have clinically useful and adequate resolution permitting:

1. set-up to be linked to internal anatomy with improved set-up precision,
2. study of individual set-up errors and organ/tumor motion (thus, individualized and narrower margins around the target can be used),
3. significantly better ability to shape the beam to precisely conform to the target and maximally exclude critical radiosensitive structures compared to other IMRT technology,
4. dose reconstruction and anatomical correlation,
5. adaptive radiotherapy,
6. collection of dose-bins data for biological optimization research,
7. efficient and direct verification of dose delivery not available with other IMRT delivery-technology.

Furthermore, the unit’s configuration, similar to a CAT scanner, eliminates the risk of gantry collisions resulting in injuries to patients and staff.

Respiratory Gated Radiation Therapy

For the purposes of radiation therapy organ motion can be subdivided in two major categories: inter- and intra-fraction. Inter-fraction organ motion is the day-to-day change in organ position due to natural physiological processes. Intra-fraction organ motion is motion that occurs on much shorter time scale, which is of the order of several seconds to several tens of seconds. Typical examples of intra-fraction motion are anatomical changes resulting from respiration, cardiac activity, muscular contractions, etcetera. Respiratory motion is considered to be the major source of intra-fraction anatomical change during radiation therapy treatment.

Respiration affects all tumor sites in the thorax and the abdomen. Lung cancer in particular accounts for 28% of all cancer deaths in the US. The five-year survival rate for lung cancer patients is 15%. Recently Radiation Therapy Oncology Group (RTOG) published results indicating that there is 18% decrease in the risk of death among the cancer patients with every 10 Gy increase in the biologically equivalent dose to the tumor. Estimates indicate that to achieve a 50% local progression-free survival at 30 months, a dose of 85 Gy should be delivered to a lung tumor. This dose level is considerably higher, due to risk of lung complications, than the dose levels routinely achievable in clinics. There is clinical evidence that technologies allowing increased tumor doses, while sparing the surrounding normal tissue, will improve the cure rate among the lung cancer patients.

Several methods that account and compensate for respiratory motion during radiation therapy have been proposed. Respiratory gating is the most widespread and used one in the readiotherapy community. Respiratory gating is a synchronization of the radiation beam with the respiration motion.

What is gating?

As can be seen from the gating example below, there is no observable difference between a static and a gated circular image. However, if a free motion (without gating) is imaged, the object shape appears deformed. The motion characteristic (amplitude and period) employed in the comparison are representative of a realistic human breathing pattern.

A gating example

4D CT and tomographic models

A computed tomography (CT) simulator, as a Must-Have imaging device in a modern radiation therapy center, is designed to provide patient anatomic information required in the treatment planning of three dimensional (3D) conformal radiotherapy and Intensity Modulated Radiation Therapy (IMRT). The four dimensional (4D) CT is one of the most appealing advancements in CT technology in recent years. Previous generations of CT simulators (3D) can only provide static images. In cases where respiratory motion is involved, only blurred time-averaging (motion artifacts) anatomic images are obtained. In contrast, a 4D CT simulator, taking advantages of its much faster speed and multiple slice capability, is able to collect a complete image set with minimal artifacts from multiple phases of a breathing cycle. With 4D images, the extension and location of the tumor at various times in breathing cycles are understood, and the developed treatment plan could provide better tumor coverage and normal tissue sparing. New treatment modalities such as respiratory gating and active tumor tracking also benefit from time information from 4D images.

The Department of Radiation Oncology at UAMS houses a Philip BrillianceTM CT Big Bore with the latest 4D technology. With a large 85 cm bore size, the CT scanner enables patients to be scanned with immobilization devices, respiratory devices and other apparatus without compromising imaging quality and positioning. The 4D CT is a part of our respiratory gating and image guided radiation therapy (IGRT) programs.

TRUS-Guided Real-Time Prostate Brachytherapy

Among men, prostate cancer accounts for one-third of all new cancers diagnosed in the United States. The American Cancer Society estimates that in 2005 over 30,000 men in the United States will die from prostate cancer and over 230,000 new cases will be diagnosed.

Prostate cancer is one of very few cancers for which there is still a debate, not just on how to treat, but whether there should be any treatment at all for some disease categories. At the present time there are several options for treating early stage prostate cancer; including surgical prostate resection (radical prostatectomy), external beam radiation therapy, brachytherapy or a combination of two or more of these modalities. Over the past several years, there is a growing volume of evidence that permanent prostate seed implant brachytherapy produces very favorable and durable biochemical survival for patients with early-state carcinoma and who have either low-, intermediate-, or high-risk features. Presently permanent seed implantation under the imaging guidance of transperineal ultrasound (TRUS) has become a very popular and viable option especially for early stage prostate cancer. Due to the convenience and a decrease in side effects, many patients are opting for this type of treatment.

In 2003, UAMS adopted the Nucletron FIRST system (Fully Integrated Real-time Seed Treatment System, Figure 1) and Nucletron SPOT Pro live planning workstation (Figure 2) to provide our patients with cutting edge technology for prostate seed implantation. Equipped with the Needle Navigator module, for the first time, clinicians can see changes in the treatment volume during the procedure using 3D Ultrasound, adapt their treatment plan to the actual clinical situation in real-time (Figure 3). Its powerful inverse planning module significantly reduces your planning time to shorten your valuable OR occupation time.

Figure 1 The automatic seed delivery system.

Figure 2 SPOR Pro treatment planning and delivery control workstation.

Figure 3 Viewbox of 3D ultrasound image and needles with seeds.

MammoSite Breast Brachytherapy

MammoSite® RTS a Less Invasive Option for Breast Cancer Patients

Mammosite is a new technique for delivering radiation treatment for only a part of the breast what is known as partial breast irradiation (PBI).

To use MammoSite® RTS for partial breast irradiation, UAMS CARTI has the following criteria:

• Patients must be older than 50
• The tumor can be no larger than 2 cm
• Tumors must be Grade 1 or 2
• Margins must be negative
• There must be no evidence of lymphovascular invasion
• Lymph nodes must be negative

Benefits of MammoSite® RTS

For eligible patients, the benefits of MammoSite® RTS is comparable to traditional whole breast radiation.

Studies have determined that the use of MammoSite® RTS is as effective as whole breast radiation. The cosmetic results may be better compared to whole breast radiation. The MammoSite® RTS procedure can be completed in five days compared to five to six weeks for whole breast radiation.

The Procedure

The MammoSite® RTS is a small balloon catheter that is inserted in the tumor cavity using ultrasound guidance. A tiny radioactive seed connected to an afterloader is inserted into the balloon and delivers the radiation. Typically the visits are for five consecutive days, with two 10-minute treatments each day. Once in place, the balloon is inflated with saline and a contrast agent inserted through an applicator shaft. The balloon remains inflated during the five-day treatment period.

The MammoSite® RTS can be inserted during the lumpectomy or in a separate procedure under local anesthesia up to 10 weeks after the lumpectomy.

Radiation is emitted by a radioactive seed attached by a wire to an afterloader. The seed is inserted through the applicator into the balloon and removed following each treatment session. The balloon is deflated and the MammoSite® RTS is removed after the last treatment.

The procedures are always done jointly by a team consisting of V. Suzanne Klimberg, M.D., chief of the Division of Breast Surgical Oncology, UAMS, Emad Youssef, M.D., in the Department of Radiation Oncology, and Yulong Yan, Ph.D., in the Division of Medical Radiation Physics and Informatics, in the Department of Radiation Oncology, for complete patient care and quality assurance.

Expansion of LDR brachytherapy program to include interstitial implants of various tumor sites

Implant or brachytherapy is the procedure in which an appropriate applicator or applicators are inserted into or in close proximity to tumors or tumor beds. Then radioactive material is loaded inside the applicator and left in place for a calculated duration to delivered very high radiation dose to the tumors and maximally spares any adjacent critical structures. It is generally used in combination with other treatment modalities (such as external beam radiation therapy) depending on the clinical scenarios and indications. The goal of the brachytherapy treatment is to maximize tumor control while keeping the complication rate at the lowest level possible. Carefully selected patients, who had failed previous treatment using external beam radiation therapy and had exhausted other treatment options, may be treated with implants for symptomatic relief.

The Department of Radiation Oncology offers implant procedures using low-dose rate radioactivity for various tumor sites such as cervical cancer, uterine cancer, soft tissue tumors, and so on. Patients are generally hospitalized for the duration of the implant, which usually lasts a few days. Patients may also be treated as out-patients using implant procedures with high-dose rate radioactivity such as lung cancer with tumors in the airways, uterine cancer, and so on. The best and most suitable implant types are selected for individual patients. We have physics, engineering, and machine shop that can build individualized or customized applicators for these special procedures if necessary. We also have special categories of implant procedures that are described separately including MammoSite for early localized breast cancer and Transrectal Ultrasound (TRUS)-Guided Real-time prostate implant.

Stereotactic Radiosurgery

Developed by Professor Lars Leksell of the Karolinska Institute in Sweden over 30 years ago, the Gamma Knife is a neurosurgical device based on the use of radioactive isotopes (Cobalt -60) used in the treatment of intracranial benign and malignant tumors, vascular malformations and certain functional disorders of the brain. With this unit in place, UAMS Medical Center is offering a treatment option to patients with brain tumors or other brain disorders once considered virtually untreatable, and can offer a noninvasive treatment alternative to patients with lesions which were once only treatable with conventional neurosurgery.

Gamma Knife radiosurgery requires the collaborative efforts from a team of specialists including neurosurgeons, radiation oncologists and radiation physicists. UAMS Gamma Knife center is jointed operated by the Department of Radiation Oncology and the Department of Neurosurgery.

To see more detailed information, the reader is referred to this webpage http://www.gammaknife.uams.edu

Thermal Theapy

Thermal therapy is a treatment used in battling cancer by heating tumors. Research has shown that heat can damage or kill cancer cells in some tumors while also making radiation therapy more effective in treating some tumors that are recurrent or progressive despite conventional therapy. While it has been known for hundreds of years that fevers can kill cancer, only relatively recently has technology been developed that can control and focus heat specifically on tumors and surrounding tissue. The Department of Radiation Oncology at UAMS strongly supports both research and clinical application of thermal therapy. The Department houses the BSD-500 system that is capable of delivering treatment in the temperature range around 41C (warm as a hot tub) that is immediately followed by radiation therapy.

The BSD-500 system has been approved by the FDA for use alone or in conjunction with radiation therapy in the palliative management of certain solid surface and subsurface malignant tumors (i.e., melanoma, squamous- or basal-cell carcinoma, adenocarcinoma, or sarcoma) that are progressive or recurrent despite conventional therapy. Clinical studies using BSD's hyperthermia systems in conjunction with radiation therapy have shown that 83.7% of patients had some tumor regression (reduction), 37.4% of patients had a complete tumor regression and 24.5% had a greater than 50% tumor regression.