About CyberKnife G4 Ukraine

CyberKnife ®G4 is one of the newest developments in the field of high medical technologies (Hi-Tech), which is based on the most modern achievements of the scientific and technological progress in the sphere of robotics, computer navigation and radiation surgery. Though its name may conjure images of scalpels and surgery, the CyberKnife treatment involves no cutting. In fact, the CyberKnife System is the world’s first and only robotic radiosurgery system designed to treat tumors throughout the body non-invasively. It provides a pain-free, non-surgical option for patients who have inoperable or surgically complex tumors, or who may be looking for an alternative to surgery.

The first installation of CyberKnife® G4 system into the clinical practice occurred in the medical centre in Stanford University (USA) under the management of neurosurgeon John Adler in the 1994. In 2001 FDA permitted the use of CyberKnife ®G4 system for the oncological diseases of any localization.

The CyberKnife ®G4 technology is not an experimental one, as far as the CyberKnife ®G4 treatment costs in the USA are covered by Medicare and large insurance companies. These costs are 20-45% smaller than the costs of traditional operations.

The use of CyberKnife ®G4 technology in the ambulatory regime makes this technology much more attractive both for the patients and for the insurance companies.

The radiosurgical session is performed in ambulatory regime, without blood, there is no infringement of ordinary patient life rhythm taking into account the food and medicine consumption. The treatment duration with CyberKnife ®G4 technology usage lasts from 30 to 90 min. The characteristic feature of this technology is its possibility of system implementation for children (there is the possibility to treat children at the age of 15 as far as there is no need for child fixation), and for spinal cord tumors treatment, which makes the CyberKnife® G4 system qualitatively different from the rest of radio surgical technologies. Moreover, it is the only system to combine a linear accelerator, robotic arm and image guidance system. The flexibility of the robotic arm allows the CyberKnife to precisely target lesions in areas of the body that are unreachable by other radiosurgery systems. The CyberKnife is also unique in its ability to continually monitor and adjust in near real-time for changes in target location during treatment. Finally, unlike most other stereotactic radiosurgery systems, the CyberKnife is able to locate and treat lesions in the head without the use of an invasive head frame.

The possibilities of CyberKnife ®G4 technology are much more excessive than all the known radio surgical methodologies. The most minor changes of patient body position during the treatment session are compensated by the computerized navigation system.

The CyberKnife is composed of a compact linear accelerator mounted on a robotic arm. The robotic arm moves the linear accelerator sequentially to multiple pre-calculated positions around the patient. At each "position", the linear accelerator fires a beam of radiation at the tumor or lesion. Image guidance cameras periodically verify target position. CyberKnife ®G4 management is performed by the computerized navigation system, which watches after each minor change of patient position while respiration and so forth. The alike system of management eliminates the need for the patient body fixation and the narcosis use. Thus, there is no need for the special patient preparation.

The CyberKnife ®G4 radiosurgery is used as the alternative for the traditional multi-week radiotherapy and for the replacement of conventional surgery intervention and connected with it hazards while the impossibility of radical elimination of the tumor.

Key Advantages

• Non-invasive alternative to surgery
• Pain free and requires no anesthesia
• Minimal side effects
• Outpatient procedure with little or no recovery time
• Allows for an immediate return to normal activities
• Treats tumors almost anywhere in the body
• Continually tracks, detects and corrects for tumor and patient movement throughout the treatment
• Delivers high-dose radiation with sub-millimeter accuracy, minimizing damage to surrounding healthy tissue
• Treats tumors from virtually unlimited directions with flexible robotic mobility
• Provides an option for patients diagnosed with inoperable or operable surgically complex tumors
• Treats patients in as few as one to five visits
• Improves patients quality of life during and after treatment

Other radiosurgical technologies

Gamma Knife

The first radiosurgical device was conceived and developed in the 1950s by Professor Lars Leksell at the Karolinska Institute in Stockholm, Sweden. His work culminated in the development of the Gamma Knife (Elekta Inc), which was used to treat patients beginning in 1968. This device is capable of precisely irradiating small intracranial (inside the skull) target with gamma ray photons. The treated lesion is targeted and the patient's head immobilized (held completely still) through the use of an external metal frame attached to the skull by four screws. A large helmet-shaped device with 201 separate, fixed "holes" or ports allows the radiation emitted by discrete (separate) radioactive cobalt-60 sources to enter the patient's head in small beams that converge on the designated target. The Gamma Knife is designed to treat intracranial targets only.

Advantages of the Gamma Knife include:

• Over 30 years of clinical use with a large number of studies published in the medical literature
• Targeting precision within 2 mm
• Multiple targets in the brain are easily treated during a single treatment sessio

Disadvantages of the Gamma Knife include:

• The basic design limits use to the brain only
• The procedure for radiation targeting requires the placement of a somewhat painful stereotactic head frame
• It can be difficult to treat patients with lesions located in certain areas (e.g. the periphery) of the brain
• It cannot be used for staged radiosurgery (delivering the radiation dose in more than one fraction or treatment session); staged radiosurgery can be particularly beneficial for larger tumors or lesions located near nerves and other sensitive structures

Linear Accelerators (LINAC)

An alternative to the Gamma Knife was developed in the mid 1980s and utilized the conventional linear accelerators (LINAC) that are commonplace in most large hospitals. By combining a series of small modifications to the radiation delivery mechanism of the LINAC with specialized planning software, it is possible to do many types of brain radiosurgery. There are both dedicated and non-dedicated LINAC-based radiosurgery devices. Dedicated LINAC systems are used solely for radiosurgery treatment. In contrast, non-dedicated systems are the daily workhorses for conventional radiation therapy departments which can also be temporarily modified to perform radiosurgery. Compared to the latter multi-purpose LINAC, dedicated systems tend to be more carefully calibrated for spatial accuracy and optimized for radiosurgical efficiency. Unlike the radioactive cobalt-based Gamma Knife, LINAC-based systems use X-ray beams generated from a linear accelerator. As a result, these devices do not require or generate any radioactive material. Common brand names for modified LINAC include XKnife™ (Radionics™ Inc).

Advantages of Multi-Purpose LINAC Radiosurgical Systems include:

• More commonplace technology in hospital

Disadvantages of Multi-Purpose LINAC Radiosurgical Systems include:

• Less accurate
• Less efficient than dedicated systems, which results in longer treatment time
• Frame-based targeting only works for brain lesions

Intensity Modulated Radiation Therapy

The recent development of IMRT or Intensity Modulated Radiation Therapy has added another dimension to multi-fraction radiation therapy. These LINAC-based technologies use computer-controlled "beam-shaping" to do a better job of conforming the radiation dose to the shape of the tumor or other lesion. This form of advanced radiation therapy can be utilized at virtually any location in the body. IMRT technology enables a mechanical device (called a multi-leaf collimator) that is typically attached to most modern medical linear accelerators, to dynamically reshape the outlines and intensity of the radiation field during cancer treatment. When combined with sophisticated planning software, IMRT fits the dose of radiation to a target much better than conventional radiation therapy, and thereby minimizes the volume of surrounding normal tissue that is injured by treatment. While it appears that IMRT may produce fewer side-effects than conventional radiation therapy, IMRT is not as spatially precise as radiosurgery. Because of this imprecision, a full course of IMRT treatment is typically administered over multiple treatment sessions (typically 20-30+). Common brand names include X-Knife™ (Radionics™) and Novalis® (Brain Lab).

Advantages of Shaped-Beam systems include:

• The capacity to treat most regions of the body with IMRT
• When coupled to an invasive stereotactic frame, precision targeting for brain tumors that approaches, but does not equal, that of the Gamma Knife or CyberKnife
• The capacity to more accurately target extracranial (non-brain) tumors than standard radiation therapy
• An ability to deliver fractionated intracranial or extracranial treatment

Disadvantages of the Shaped Beam systems include:

• The need for an invasive head frame (similar to the Gamma Knife) to assure treatment accuracy when used for brain radiosurgery (single fraction)
• Less treatment accuracy when multiple fractions are used to treat areas of the brain where the use of an invasive head frame is impractical
• A significantly lesser degree of targeting accuracy when treating extracranial tumors compared to brain radiosurgery
• Treatment accuracy is degraded further when the target moves during radiation delivery from either natural breathing or patient movement

CyberKnife® Robotic Radiosurgery System

The CyberKnife System is a stereotactic radiosurgery system utilizing contemporary technology that is designed for sub-millimeter accuracy and flexibility. The CyberKnife was designed to address the limitations of frame-based stereotactic radiosurgery systems and expands the application of radiosurgery to sites outside of the head. It is the only system to incorporate a miniature linear accelerator mounted on a flexible, robotic arm. An image-guidance system that can track target location during treatment also enables the CyberKnife to offer superior targeting accuracy without the need for the invasive head frame. While Gamma Knife and LINAC-based systems can perform radiosurgery in the brain, true radiosurgery for areas outside of the brain is difficult if not impossible to perform with these systems.

Advantages of the CyberKnife include:

• No invasive head frame or other rigid immobilization device is required
• The ability to perform radiosurgery (1-5 fractions/stages) on targets throughout the body, not just the brain
• Precise targeting of selected lesions in the brain and body
• A unique ability to provide real time monitoring of the treated target throughout treatment using an advanced image-guidance system
• A unique ability to correct during treatment for limited target motion (e.g. due to small patient movements)
• The capacity to easily perform staged radiosurgery

Disadvantages of the CyberKnife include:

• Some tumors require the placement of very small markers (fiducials) via a needle for the treatment of targets outside of the head

Compared to other radiosurgical devices, treatment takes longer when multiple tumors are ablated during the same treatment session.