Steam ablation equipment

Abstract

The invention discloses steam ablation equipment which comprises an industrial personal computer, a steam generator, a gear pump system based on PID self-regulation, a heat tracing pipe, a sensor, an upper computer and an electromagnetic valve. The temperature index of steam output is controlled, the steam outlet pressure is controlled, and it can be known through simulation that in steam ablation, the temperature and the outlet pressure have important influences on the ablation effect; in order to realize accurate control of air pressure, a gear pump system based on PID self-regulation is adopted to realize closed-loop control of air outlet pressure; in order to realize accurate temperature control, the steam generator is divided into a vaporizing chamber and a heating chamber; the air outlet pressure and the air outlet temperature can be set at will, and by matching with different steam outlet needles, the device can be applied to the field of steam ablation in various occasions, such as chronic obstructive pulmonary disease, prostate and tumor fields possibly involved in the future.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and particularly to a steam ablation device. Background Art

[0002] Steam ablation is to minimally intervene saturated steam (steam molecules) carrying a large amount of heat into the target area of the patient. When the steam molecules condense back into liquid water, a large amount of heat is released into the target area of the patient, resulting in protein coagulation and ultimately cell death. Compared with traditional ablation techniques (microwave ablation, radiofrequency ablation, laser ablation), steam ablation has the advantages of low cost, no carbonization, no electromagnetic radiation, and can be used in combination with drugs.

[0003] Current steam ablation treatment devices (such as Rezūm water vapor ablation treatment system, InterVapor steam ablation system) can only treat benign prostatic hyperplasia and chronic obstructive pulmonary disease. Due to the lack of precise control of air pressure, currently only temperature and time are selected as ablation parameters in clinical practice, and the ablation tissues mainly focus on the application in hollow tissues, such as the prostate, lungs, and veins. Such tissues have a volume that can expand and change, and have good adaptability to the absorption and diffusion of steam. Therefore, the demand for steam pressure parameters is small. Summary of the Invention

[0004] Object of the Invention: The present invention provides a steam ablation device that can arbitrarily set the outlet air pressure and outlet temperature. By matching different steam outlet needles, it can be applied to the steam ablation field in various scenarios.

[0005] Technical Solution: A steam ablation device according to the present invention includes: an industrial control computer, a steam generator, a gear pump system based on PID self-regulation, a heat tracing pipe, a sensor, a host computer, and a solenoid valve; the gear pump system based on PID self-regulation is connected to the steam generator. The value of the outlet air pressure is set through the industrial control computer. The gear pump system based on PID self-regulation automatically adjusts the water inlet flow according to the measured value of the steam outlet pressure sensor. The steam generator sets its vaporization temperature and outlet temperature through the industrial control computer, ensuring that the outlet steam temperature and outlet air pressure of the steam ablation device are adjustable. The ablation time is set through the industrial control computer. After the real-time vaporization temperature, outlet temperature, heat tracing temperature, and outlet air pressure monitored by the sensor reach the set values, the solenoid valve switches the outlet to the main air duct and starts to output steam. During the remaining time, the solenoid valve switches to the secondary air duct, and the output steam enters the air release water tank, thereby maintaining the closed-loop dynamic balance of the gear pump system based on PID self-regulation. The heat tracing pipe is connected to the main air duct of the solenoid valve, and the heat tracing temperature is set through the industrial control computer, which can control and reduce the heat loss between the steam generator and the self-made steam ablation needle.

[0006] Further, isolate the steam generator into a vaporization chamber and a heating chamber, set its vaporization temperature and outlet temperature through an industrial control computer, and the set vaporization temperature should be lower than the outlet temperature; the water passing through the gear pump system based on PID self-regulation first goes to the vaporization chamber for the first heating and vaporization, and the vaporized water molecules enter the heating chamber for the second heating. The outlet temperature sensor real-time feeds back the current vaporization temperature of the vaporization chamber and the outlet temperature of the heating chamber. After the outlet temperature reaches the same as the set value, one of the necessary conditions for the solenoid valve to switch the air outlet to the main air duct is satisfied.

[0007] Further, the tracing pipe is connected to the main air duct of the solenoid valve. There is a heating coil in the tracing pipe to realize the third heating of the steam conduit wrapped in the tracing pipe, which can reduce the heat loss between the steam generator and the self-made steam ablation needle.

[0008] Further, set the tracing temperature through the industrial control computer, and the temperature of the tracing pipe should be set higher than the outlet temperature to avoid heat loss caused by the lower tracing temperature after the steam comes out of the main air duct of the solenoid valve.

[0009] Further, the upper computer includes a human-machine interaction interface to set the parameter values of the vaporization temperature, outlet temperature, tracing temperature and outlet air pressure of the steam generating device and real-time display the current vaporization temperature, outlet temperature, tracing temperature and outlet air pressure of the steam generating device.

[0010] Further, the gear pump system based on PID self-regulation uses the proportional-integral-differential algorithm to achieve closed-loop control. The expression of the output signal under the PID algorithm control is:

[0011]

[0012] e(t)=r(t)-y(t)

[0013] In the formula: u(t) is the output signal of the PID controller; r(t) is the given steam pressure signal; y(t) is the actually measured steam pressure signal; e(t) is the difference between the given value r(t) and the actually measured value y(t); Kp is the proportional gain; Tt is the integral time constant; TD is the differential time constant.

[0014] Further, the gear pump system based on PID self-regulation uses the proportional-integral-differential algorithm to return the steam outlet pressure collected by the steam outlet pressure sensor to the input port node, compare and subtract it from the set steam outlet pressure, and obtain the output value through the PID link and bring it into the gear pump system based on PID self-regulation, so as to be able to meet the real-time closed-loop regulation of the outlet steam pressure.

[0015] Beneficial effects: Compared with the prior art, the present invention has the following remarkable advantages: (1) In addition to controlling the temperature index of steam output, the present invention also controls the steam outlet pressure. Through simulation, it can be known that in steam ablation, in addition to temperature, the outlet pressure also has an important impact on the ablation effect; (2) In order to achieve precise control of the pressure, the present invention adopts a gear pump system with PID self-regulation to realize the closed-loop control of the outlet pressure; (3) In order to achieve precise control of the temperature, the present invention isolates the steam generator into a vaporization chamber and a heating chamber; (4) The present invention can arbitrarily set the outlet pressure and the outlet temperature. By matching different steam outlet needles, it can be applied to the steam ablation field in various occasions, such as chronic obstructive pulmonary disease, prostate, and the future possible tumor field, etc. Brief Description of the Drawings

[0016] Figure 1 It is a block diagram of the steam ablation device of the present invention.

[0017] Figure 2 It is a structural diagram of the steam ablation device of the present invention.

[0018] Figure 3 It is a structural diagram of the heat tracing system of the present invention.

[0019] Figure 4 It is an internal heating diagram of the steam generator system of the present invention.

[0020] Figure 5 It is a diagram of the ablation results of ex vivo porcine liver under different pressures of the present invention.

[0021] Figure 6 It is a diagram of the ablation results of ex vivo porcine liver at different times of the present invention.

[0022] Figure 7 It is a schematic diagram of the PID algorithm of the gear pump system with PID self-regulation of the present invention. Detailed Description of the Invention

[0023] Such as Figure 1As shown in the figure, a steam ablation device includes: an industrial control computer, a steam generator, a gear pump system based on PID self-regulation, a tracing pipe, sensors, a host computer, and a solenoid valve; the gear pump system based on PID self-regulation is connected to the steam generator, and the value of the outlet air pressure is set through the industrial control computer. The gear pump system based on PID self-regulation can automatically adjust the water inlet flow according to the measured value of the steam outlet pressure sensor; the steam generator sets its vaporization temperature and outlet temperature through the industrial control computer; overall, it ensures that the outlet steam temperature and outlet air pressure of the steam ablation device are adjustable; the ablation time is set through the industrial control computer. After the real-time vaporization temperature, outlet temperature, tracing temperature, and outlet air pressure monitored by the sensors reach the set values, the solenoid valve switches the air outlet to the main air outlet channel and starts to output steam. During the remaining time, the solenoid valve switches to the secondary air outlet channel, and the output steam enters the air release water tank, thereby maintaining the closed-loop dynamic balance of the gear pump system based on PID self-regulation. The tracing pipe is connected to the main air outlet channel of the solenoid valve, and the tracing temperature is set through the industrial control computer, which can control and reduce the heat loss between the steam generator and the self-made steam ablation needle.

[0024] As Figure 2 shown in the figure, the internal structure of the steam ablation device mainly includes an industrial control computer, a steam generator, a gear pump system based on PID self-regulation, and a solenoid valve; the tracing pipe is independent of the internal structure and belongs to an externally installed device. The temperature sensor is integrated inside the steam generator.

[0025] As Figure 3 shown in the figure, the tracing system mainly consists of heat insulation cotton, heating coils, and a tracing pipe. Since air has a very large specific heat capacity and the steam will immediately drop to around 100 degrees Celsius when it comes into contact with the outside world, it is particularly important to solve the heat loss of the steam during the distance from the steam generator to the needle tip. A tracing system is added outside the connecting pipe between the ablation needle and the steam generator. The tracing temperature can be set from 100 to 200 degrees Celsius through the host computer, and it has good heat preservation and heat insulation properties and will not cause harm to the user during operation. It conducts heat preservation treatment on the steam during the transmission process and reduces its heat energy loss during the transmission process.

[0026] As Figure 4 shown in the figure, for the steam generator to achieve precise temperature control, the steam generator is separated into a vaporization chamber and a heating chamber. Its vaporization temperature and outlet temperature are set through the industrial control computer, and the set vaporization temperature is lower than the outlet temperature; the water passing through the gear pump first enters the vaporization chamber for the first heating and vaporization, and the vaporized water molecules enter the heating chamber for the second heating. The outlet temperature sensor real-time feeds back the current vaporization temperature of the vaporization chamber and the outlet temperature of the heating chamber. Only after the outlet temperature reaches the same as the set value can it meet one of the necessary conditions for the solenoid valve to switch the air outlet to the main air outlet channel.

[0027] AsFigure 5 As shown, set the outlet steam temperature to 120 °C, the air pressure to 100 KPa, and the time to 3 minutes. The ablation result is as Figure 5 (a) shows. Its major axis is 22 mm, the minor axis is 20 mm, and the axial ratio is 90.9%, approximately a circle. Adjust the air pressure to twice and three times the original, and observe the changes in its major and minor axes and the axial ratio. Figure 5 (b) is the ablation result with an outlet steam temperature of 120 °C, an air pressure of 200 KPa, and a time of 3 minutes. Its major axis is 25 mm and the minor axis is 22 mm. Compared with the Figure 5 (a) parameters, the major axis increases by 3 mm, the minor axis increases by 2 mm, the overall ablation area increases, and the axial ratio is 88%, also approximately a circle. Figure 5 (c) is the ablation result with an outlet steam temperature of 120 °C, an air pressure of 300 KPa, and a time of 3 minutes. Its major axis is 32 mm and the minor axis is 28 mm. Compared with the Figure 5 (a) parameters, the major axis increases by 10 mm, the minor axis increases by 8 mm, the overall ablation area further increases, and the axial ratio is 87.5%, also approximately a circle. During the steam ablation of liver tumors, the ablation area can be increased by changing the air pressure parameter. At the same time, from Figure 5 (a)5(b)5(c), it can be seen that compared with traditional minimally invasive thermal ablation techniques such as microwave ablation, radiofrequency ablation, and laser ablation, there is no carbonization and it has the largest axial ratio.

[0028] As Figure 6 shown, set the outlet steam temperature to 120 °C, the air pressure to 100 KPa, and the time to 5 minutes. The ablation result is as Figure 6 (a) shows. Its major axis is 36 mm, the minor axis is 32 mm, and the axial ratio is 91.4%, approximately a circle. Adjust the time to 7 minutes and 10 minutes, and observe the changes in its major and minor axes and the axial ratio. Figure 6 (b) is the ablation result with an outlet steam temperature of 120 °C, an air pressure of 100 KPa, and a time of 7 minutes. Its major axis is 50 mm and the minor axis is 44 mm. Compared with the Figure 6 (a) parameters, the major axis increases by 14 mm, the minor axis increases by 12 mm, the overall ablation area increases, and the axial ratio is 88%, also approximately a circle. Figure 6 (c) is the ablation result with an outlet steam temperature of 120 °C, an air pressure of 100 KPa, and a time of 10 minutes. Its major axis is 65 mm and the minor axis is 58 mm. Compared with the Figure 6 (a) parameters, the major axis increases by 31 mm, the minor axis increases by 26 mm, the overall ablation area further increases, and the axial ratio is 89.2%, also approximately a circle. During the steam ablation of liver tumors, the ablation area can be increased by changing the ablation time parameter. At the same time, no carbonization phenomenon occurs regardless of the ablation time.

[0029] AsFigure 7 As shown, in the gear pump system based on PID self-regulation, the actual output value (steam outlet pressure) is collected by a detection device (steam outlet pressure sensor) and returned to the input port node, where it is compared with the set steam outlet pressure and the difference is calculated. The comparison error is processed through a PID link (proportional, integral, and differential algorithms) to obtain an output value, which is then input into the actuator (gear pump system with PID self-regulation), so as to achieve real-time closed-loop regulation of the outlet steam pressure. The gear pump system based on PID self-regulation uses the proportional-integral-differential algorithm to achieve closed-loop control. Closed-loop control is a control method that corrects according to the output feedback of the controlled object. It corrects according to the quota or standard when the deviation between the actual and the planned is measured. PID control combines the three functions of proportional, integral, and differential. It can not only accelerate the system response speed, reduce oscillation, and overcome overshoot, but also effectively eliminate the static error, greatly improving the static and dynamic qualities of the system. The closed-loop control based on the PID algorithm has the advantages of fast response, high stability, and no steady-state error.

Claims

1. A steam ablation device, characterized in that: include: Industrial computer, steam generator, gear pump system based on PID self-regulation, heating pipe, sensor, host computer and solenoid valve; The gear pump system based on PID self-regulation is connected to the steam generator, and the value of the outlet air pressure is set through the industrial computer. The gear pump system based on PID self-regulation spontaneously adjusts the water inlet flow rate according to the measurement value of the steam outlet pressure sensor. The steam generator sets its vaporization temperature and outlet temperature through the industrial computer, which ensures that the steam outlet temperature and outlet air pressure of the steam ablation equipment are adjustable as a whole; the ablation time is set through the industrial computer, and when the real-time vaporization temperature, outlet temperature, heating temperature and outlet air pressure monitored by the sensor reach the set value, the solenoid valve switches the outlet to the main outlet and starts to output steam. During the rest of the time, the solenoid valve switches to the auxiliary outlet, and the output steam enters the deflation water tank, thereby maintaining the closed-loop dynamic balance of the gear pump system based on PID self-regulation. The heating pipe is connected to the main outlet of the solenoid valve. The heating temperature is set through the industrial computer, which can control and reduce the heat loss between the steam generator and the homemade steam ablation needle.

2. The steam ablation device according to claim 1, characterized in that: Isolate the steam generator from the vaporization chamber and the heating chamber, and set its vaporization temperature and outlet temperature through the industrial computer. The vaporization temperature should be set lower than the outlet temperature. The water passing through the gear pump system based on PID self-regulation first goes to the vaporization chamber for the first heating and vaporization. The vaporized water molecules enter the heating chamber for the second heating. The outlet temperature sensor feeds back the current vaporization temperature of the vaporization chamber and the outlet temperature of the heating chamber in real time. When the outlet temperature reaches the set value, one of the necessary conditions for the solenoid valve to switch the outlet to the main outlet is met.

3. The steam ablation device according to claim 1, characterized in that: The heating pipe is connected to the main air outlet of the solenoid valve. A heating coil is arranged in the heating pipe to realize three-stage heating of the steam conduit wrapped in the heating pipe.

4. The steam ablation device according to claim 1, characterized in that: The heating temperature is set through the industrial computer, and the temperature of the heating pipe should be set higher than the outlet temperature.

5. The steam ablation device according to claim 1, characterized in that: The upper computer includes a human-computer interaction interface for setting parameter values ​​of vaporization temperature, outlet temperature, heating temperature and outlet pressure of the steam generating equipment and for displaying the current vaporization temperature, outlet temperature, heating temperature and outlet pressure of the steam generating equipment in real time.

6. The steam ablation device according to claim 1, characterized in that: The gear pump system based on PID self-regulation adopts proportional-integral-differential algorithm to realize closed-loop control. The output signal expression under PID algorithm control is: e(t)=r(t)-y(t) Where: u(t) is the output signal of the PID controller; r(t) is the given steam pressure signal; y(t) is the actual measured steam pressure signal; e(t) is the difference between the given value r(t) and the actual measured value y(t); Kp is the proportional gain; Tt is the integral time constant; TD is the differential time constant.

7. The steam ablation device according to claim 1, characterized in that: The gear pump system based on PID self-regulation adopts the proportional-integral-differential algorithm, returns the steam outlet pressure collected by the steam outlet pressure sensor to the input port node, compares it with the set steam outlet pressure, and obtains the output value through the PID link, which is brought into the PID self-regulating gear pump system, thereby meeting the real-time closed-loop control of the outlet steam pressure.

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