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BSD-2000 Hyperthermia System
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The BSD-2000 provides deep regional therapeutic hyperthermia to solid tumors by applying radiofrequency (RF) energy at the frequency range of 75 to 120 MHz. The BSD-2000 delivers energy to a patient using a power source and an array of multiple antennae that surround the patient’s body. The BSD-2000 was designed to provide an optimized heating zone targeted to the tumor region by utilizing the adjustment of frequency, phase, and amplitude from multiple power sources. The energy can be focused electronically to the tumor region, thus providing dynamic control of the heating delivered to the tumor region.
During a treatment, the cancerous tumor is heated to 40 and 45°C (104 -113 °F). Hyperthermia damages cells in solid tumors, without damaging normal tissues, because higher temperatures selectively damage cells that are hypoxic and have low pH, a condition of tumor cells and not a condition of normal cells. Hyperthermia has been shown to inhibit cellular repair mechanisms, induce heat-shock proteins, denature proteins, induce apoptosis, and inhibit angiogenesis.
Hyperthermia increases the effectiveness of radiation therapy due to the independent cytotoxic effects of hyperthermia combined with its radiosensitizing effects. Hyperthermia increases blood flow, resulting in improved tissue oxygenation and thus increased radiosensitivity. Hyperthermia also interferes with cellular repair of the DNA damage caused by radiation. Hyperthermia damages cells that are hypoxic, have a low pH, and are in the S-phase of division, which are all conditions that make cells radioresistant. The addition of hyperthermia to radiation treatment does not usually increase the toxicity of radiation therapy.
The BSD-2000 consists of four major subsystems.
- RF power delivery subsystem.
- Proprietary, thermistor-based, thermometry subsystem.
- Computerized monitoring and control subsystem.
- Applicator subsystem that includes an applicator and patient support system.
- Various accessories, including a tissue equivalent QA lamp phantom that provides verification of the energy focus, pattern steering, and system operations.
The BSD-2000 comes in two configurations, a lower power basic system (BSD-2000B) that has a maximum power output of 1300 watts and an upgraded higher power system (BSD-2000U) that has a maximum power output of 1800 watts. The standard treatment usually involves the use of the 1300 watt BSD-2000B, while the 1800 watt BSD-2000U is reserved for larger patients.
- Solid-state amplifier with 4-channel independent phase and amplitude adjustment capability.
- The maximum power per channel is 25% of the maximum output power of all channels.
- Phase accuracy within a 10 degree tolerance.
- Computer automatically monitors and controls forward and reflected power, phase, and power on each channel.
- Optimized treatment settings are calculated through the use of treatment planning software tools provided with the system.
- Non-perturbing, electromagnetically insensitive, temperature sensors with an accuracy of +0.2°C over a range of 25 to 52°C.
- Automated positioning system allows the operator to map the sensor along the length of the catheter in order to determine the temperature profile.
- Precise calibration capabilities - accurate to 0.05°C over a range of 0°C to 60°C.
- Optimized power coupling.
- Optimized patient comfort.
- Water system automatically fills the bolus and controls the bolus water temperature.
- Fabric sling comfortably supports patient inside the applicator.
- Easy patient access and handling.
- Quick drain capability allows fast access to the patient – 15 seconds for patient access and 30 seconds for a complete drain.
- User friendly, intuitive, color graphics interface.
- Step-by-step guide for setup and treatment procedure.
- Icon selectable adjustments of the treatment parameters.
- Tabs allow operator to easily switch between screen displays.
- Closed -loop feedback system provides automatic monitoring and control of treatment parameters, including power output, frequency, amplitude and phase, tissue temperatures, core temperature, and treatment time.
- System automatically records, displays, and prints patient treatment data.
- Control of power and tissue temperature to within ±0.1°C.
- Data regarding temperatures, RF power level, and RF power control updated every 2 seconds.
- Control algorithms smoothly adjust heating and cooling rates.
- The system controls the applied power level in accordance with operator inputs and automatically adjusts the level of power to maintain the operator selected temperatures throughout the treatment.
- The computer automatically performs numerous safety checks to ensure proper operation of the system and ensure safety for the patient and the operator.
The Sigma applicators (Sigma 60 and Sigma Ellipse) are annular phased array applicators that are comprised of a clear plastic shell, 8 radiating dipoles, and a bolus membrane. The Sigma 60 uses a cylindrical shaped plastic shell to support the 8 radiating dipoles. The Sigma Ellipse is an elliptically shaped plastic shell used to support the same components used in the Sigma 60. The Sigma Ellipse provides improved comfort for smaller size patients.
- Advanced annular phased array principles create a central focusing of energy, which significantly overcomes the penetration losses of the energy radiated into the body.
- Phased array applicators allow the operator to shape the heating pattern to the targeted treatment area and achieve selective power targeting at depth for treatment of deep tumors.
- Dipoles are covered by a thin dielectric layer to prevent contact with the bolus water.
- Water filled bolus dielectrically loads the individual antennas and provides an energy-confining medium that directs the RF energy into the body.
- Quick and easy patient setup.
- Plastic shell provides a clear view of the patient’s surface to allow visual verification of the applicator positioning and to facilitate monitoring of any skin color changes, which would be indicative of surface hot spots.
A Phase III randomized study was conducted at Erasmus Medical Center – Daniel den Hoed Cancer Center (DHCC), Rotterdam, The Netherlands, to compare hyperthermia (HT), delivered using the BSD-2000, and radiation (RT) to RT only treatment of 65 advanced cervical cancer patients, referred to as the BSD Intent-to-Treat (“BSD ITT”) population. 33 patients were randomized into RT combined with HT and 32 were randomized into RT alone. All patients had prognostic indicators that are associated with a poorer outcome for cervical cancer. The study met its primary endpoint of a 20% increase in complete response rates for cervical cancer patients receiving HT and RT as compared to RT alone. (Complete response [CR] was defined as disappearance of all viable tumor in the irradiated volume.) These data were a subset of the Deep Dutch Hyperthermia Trial data that were published in The Lancet. (Van der Zee J, Gonzalez-Gonzalez D, Van Rhoon GC, et al. Comparison of radiotherapy alone with radiotherapy plus hyperthermia in locally advanced pelvic tumours: a prospective, randomised, multicentre trial. Lancet 2000;355:1119-1125.)
Humanitarian Use Device. In the U.S., the BSD- 2000 has a Humanitarian Device Exemption (HDE) approval for use in conjunction with radiation therapy in the treatment of cervical carcinoma patients who would normally be treated with combined chemotherapy and radiation but are ineligible for chemotherapy due to patient related factors. The effectiveness of this device for this use has not been demonstrated.
See BSD-2000 Essential Prescribing Information for complete information on the FDA approved indications for use and side effects.
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