Frequently Asked Questions

The Radixact System, the next-generation TomoTherapy® platform, has been designed to enable doctors to more effectively and efficiently deliver precise radiation treatments to more patients. The TomoTherapy platform represented a dramatic advance in the radiation oncology field, as the only system specifically designed for integrated 3D daily image-guidance with intensity modulated radiation therapy (IG-IMRT) to help patients control their cancer. The TomoTherapy technology, used in the Radixact System, has more than two decades of clinical evidence and has been used to help thousands of cancer patients. Today, the Radixact System is routinely used to treat a variety of cancers – from routine to complex tumors, those located in hard-to-reach areas, recurrent tumors and cancers of the skin and blood.

The FDA provided clearance for the TomoTherapy technology for the treatment of tumors anywhere in the body, including rectal cancers, in 2002. The next generation of the TomoTherapy platform, the Radixact System, was cleared in 2016.

    • Patients enrolled in two studies received simultaneous daily radiation and a targeted radiation boost over a 25-session time period. The TomoTherapy platform’s unique architecture enabled the delivery of a high dose of radiation, directly to the tumor, through the integrated boost of radiation, while minimizing radiation dose delivered to organs in close proximity to the targeted tumor. Patients in the studies experienced improved treatment results and reduced side effects 1 , 2.
    • Treatment with TomoHelical™ and TomoDirect™ is safe, with low rates of severe toxicity. Radiation delivered with helical TomoTherapy following daily imaging with the platform’s integrated imaging capabilities allowed for the reduction of treatment margins around the tumor, so less normal tissue was irradiated. The authors highlighted a “clear reduction in the rates of acute and late non-hematological toxicities” when compared to a randomized trial evaluating the use of 2D- or conformal 3D-RT techniques, published in the New England Journal of Medicine (NEJM) 3.
  • TomoHelical used simultaneously to deliver daily radiation treatments and a targeted radiation dose boost to the primary tumor was able to significantly reduce the volume of the tumor, while minimizing dose to surrounding organs-at-risk. This enabled surgeons to perform sphincter-preserving surgery while removing the remaining tumor in 80.1 percent of patients in the study, thereby increasing the chance of maintaining normal bowel function and preserving quality of life2.

Radixact treatment is available at many locations worldwide. TomoTherapy treatments are available at hundreds of locations worldwide.

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The helical design of the Radixact System – unique among radiation therapy systems – enables multiple 360-degree rotation radiation dose delivery as the treatment table moves the patient at a deliberate pace through the center of the system. The Radixact System revolves around you while thousands of “beamlets” – smaller than the radiation beams of conventional systems – are delivered to the tumor. Each beamlet can deliver a different dose of radiation. Different doses go to different parts of each tumor, with less damage to surrounding healthy tissue.

Integrated imaging and advanced dose-delivery capabilities enable your treatment team to create a more personalized treatment plan and confidently deliver the most precise dose of radiation, directly to the tumor. Radixact helical delivery also enables treatment of a full range of diseases, including larger, more complex tumors, multiple tumors, and recurrent tumors.

Radixact treatments are completed in one to several weeks, similar to conventional radiation therapy.

Put simply, helical delivery means that the source of the radiation beam(s) (the linear accelerator or LINAC), can move in multiple 360-degree rotations around the patient during treatment delivery while the treatment table moves the patient at a deliberate pace through the center of the system. Whereas conventional radiation therapy systems can only deliver radiation from a limited number of points, the helical delivery of the Radixact System helps to allow your treatment team to administer the accurate dose of radiation to the tumor from 360 degrees around the patient.

Radiation therapy is a treatment that uses high-energy X-rays (photons) to destroy cancer cells and shrink or control the growth of tumors. Radiation therapy works by damaging cells, disabling them from growing and dividing. The goal of any radiation treatment is to destroy cancer cells while helping minimize dose to healthy tissue. As imaging technologies have advanced over the past several decades, radiation therapy has integrated those upgrades to help enhance dose delivery, improve outcomes and reduce the side effects of treatment.

Radiation is a proven cornerstone of effective treatment for many rectal cancers, and may be combined with other treatments including surgery, chemotherapy and brachytherapy. Radiation therapy is constantly evolving with the introduction of new technologies to the market. The Radixact System can deliver a highly advanced type of radiation therapy known as image-guided, intensity-modulated radiation therapy (IG-IMRT).

Intensity-modulated radiation therapy (IMRT) is a specialized form of external beam radiation therapy that varies the intensity of each radiation beam. IMRT can help clinicians shape the delivery of radiation to fit the contours of the tumor more accurately and precisely – and help minimize dose to surrounding organs and tissues.

Image-guided intensity-modulated radiation therapy (IG-IMRT) is a type of targeted external beam radiation therapy that enhances IMRT by using images acquired before each treatment to help ensure accurate patient and tumor positioning before delivery of the radiation treatment.

With daily imaging, clinicians gain the confidence necessary to accurately set-up the patient on the table before treatment and reduce margins throughout the course of the treatment. And by modulating the intensity of the radiation beams/beamlets, IG-IMRT enables clinicians to carefully shape the radiation dose to fit the contours of the target(s), while minimizing dose to surrounding organs and other healthy tissues. This precision and accuracy is particularly valuable when it comes to minimizing dose to the digestive tract, bladder and reproductive organs.

There are more options than ever for treating rectal cancers, and the right option depends on your specific diagnosis. The Radixact System is typically used to treat locally advanced rectal cancer. The best way to determine if Radixact treatment is right for you is to find a Radixact treatment location and make an appointment to discuss your specific details.

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Most radiation side effects are minimal and last only a short time. Side effects can, however, be severe. Possible short-term side effects could include:

  • Skin irritation, blistering and peeling
  • Nausea
  • Rectal irritation
  • Bowel incontinence (stool leakage)
  • Bladder irritation
  • Fatigue
  • Sexual issues (erection issues in men and vaginal irritation and/or pain in women)

Long-term side effects could include:
  • Scarring, fibrosis
  • Digestive and urinary problems
  • Sexual issues

Ask your doctor for more details about the side effects of your specific radiation therapy. Learn More About Potential Side Effects

You can expect your Radixact treatment to require daily sessions over one to five weeks. Because the Radixact System can deliver radiation continuously, without requiring interruptions to reposition, the entire treatment process typically lasts 10-20 minutes – including patient set-up time.

Treatment sessions are non-invasive outpatient procedures, and no anesthesia is required. Most patients resume normal activity immediately after treatment sessions.

No anesthesia is required for Radixact treatment and treatment sessions are completed on an outpatient basis.

The majority of patients can continue normal activity during and immediately following Radixact treatment – compared to the typical requirement to limit normal activity for one to several weeks after traditional surgery. Just as important, the Radixact System is designed to minimize dose to healthy tissues and reduce the incidence of side effects, with the goal of improving patient quality of life both during and after treatment. In some circumstances, side effects may occur.

The majority of patients can continue normal activity during and immediately following Radixact treatment — compared to the typical requirement to limit normal activity for several weeks after traditional surgery. Many patients experience minimal side effects and can quickly return to their daily routines.

Radiation delivered to organs surrounding the rectum, such as the bowel and bladder, may lead to life-changing side effects, making it critically important for the radiation to be delivered with extreme accuracy and precision. Additionally, precise dose delivery is essential for optimizing long-term disease control.

Because the precise targeting of the Radixact System significantly reduces irradiation of surrounding healthy tissues, some patients previously treated with conventional radiation therapy systems or IMRT may be candidates for re-irradiation with the Radixact System, in the event of recurrence. Patients should consult their physician regarding their specific case.

Medicare and private insurance companies in the United States may reimburse image-guided IMRT for rectal cancers subject to medical necessity and your health insurance plan constraints. Patients should contact a Radixact treatment center to determine if this procedure is a covered benefit under your health insurance plan and any out-of-pockets costs such as deductibles, co-insurances, and/or copayments.

Not every patient’s condition is effectively treated with IG-IMRT. Talk to your physician about the best options and come to a joint decision.


[1] De Bari, B., Franzetti-Pellanda, A., Saidi, A. et al. Neoadjuvant chemoradiotherapy delivered with helical tomotherapy under daily image guidance for rectal cancer patients: efficacy and safety in a large, multi-institutional series. J Cancer Res Clin Oncol 145, 1075–1084 (2019).

[2] Zhao, J., Liu, X., Wang, W. et al. Concomitant dose escalation with image-guided Tomotherapy in locally advanced mid–low rectal cancer: a single-center study. ted. Cancer Management and Research 2019:11 1579–1586.

[3] Sauer R, et al: Preoperative versus Postoperative Chemoradiotherapy for Rectal Cancer. N Engl J Med. 2004 Oct 21;351(17):1731-40.

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Important Safety Statement: Most side effects of radiotherapy, including radiotherapy delivered with Accuray systems, are mild and temporary, often involving fatigue, nausea, and skin irritation. Side effects can be severe, however, leading to pain, alterations in normal body functions (for example, urinary or salivary function), deterioration of quality of life, permanent injury and even death. Side effects can occur during or shortly after radiation treatment or in the months and years following radiation. The nature and severity of side effects depend on many factors, including the size and location of the treated tumor, the treatment technique (for example, the radiation dose), the patient’s general medical condition, to name a few. For more details about the side effects of your radiation therapy, and if treatment with an Accuray product is right for you, ask your doctor.