JPH11276604A - Laser device for PDT - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a temperature sensor for a PDT in which the temperature sensor can detect the temperature of a laser diode more accurately than before, on the premise that the wavelength of an excitation laser is controlled to a constant value based on the output of the temperature sensor. Providing laser equipment, etc. SOLUTION: A laser diode 1 for outputting an excitation laser, an electronic cooling element 2 for changing the wavelength of the output laser by heating and cooling the laser diode 1,
A temperature sensor 3 for detecting the temperature of the laser diode 1,
A temperature controller 4 as a control unit for controlling heat exchange by the electronic cooling element 2 based on the output of the temperature sensor 3 and controlling the wavelength of the laser to a predetermined constant wavelength is provided in the housing 5. . In particular, the temperature sensor 3 is disposed between the laser diode 1 and the thermoelectric cooler 2, and in this state, the laser diode 1 and the thermoelectric cooler 2
And proximity equipment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a PDT (Photodyn)
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser device for amic therapy (photodynamic therapy), and more particularly, to a laser device for PDT used for cancer treatment in the medical field.

[0002]

2. Description of the Related Art As a conventional example of a PDT laser device, there is JP-A-6-246014. In the device described in this publication, a semiconductor laser is used as a light source, and the wavelength of the laser is controlled to be constant by controlling the temperature of the light source. This makes it possible to efficiently excite the photosensitizer injected into the patient's body.

[0003]

Here, when controlling the temperature of the light source, it is natural that air having a temperature different from the temperature of the light source flows in the housing. When performing feedback control using a temperature sensor, depending on the mounting position of the temperature sensor in the housing, air in the housing may cause an error in the temperature measurement of the light source and cause the laser wavelength to deviate from an ideal value. Was.

[0004]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned inconveniences. In particular, it is assumed that the wavelength of the excitation laser is controlled to a constant value based on the output of the temperature sensor. It is an object of the present invention to provide a PDT laser device capable of detecting a PDT. It is another object of the present invention to achieve this object by devising the arrangement of physical elements in the housing, and to realize relatively high-accuracy detection without using signal processing means such as output correction means.

[0005]

In order to achieve the above object, the present invention provides a laser diode for outputting an excitation laser, and an electronic cooling element for changing the wavelength of the output laser by heating and cooling the laser diode. , A temperature sensor for detecting the temperature of the laser diode, and a control unit for controlling the heat exchange by the electronic cooling element based on the output of the temperature sensor and controlling the wavelength of the laser to a predetermined constant wavelength are provided in the housing. In particular, the laser diode and the thermoelectric cooler are provided close to each other with the temperature sensor being disposed between the laser diode and the thermoelectric cooler. In addition, an intake port and an exhaust port capable of forcibly ventilating the air in the housing are provided on the housing surface. This aims to achieve the above-mentioned object.

[0006] In the present invention, air is taken in from the intake port, and heat is taken out or transferred to the electronic cooling element. The air is exhausted from the exhaust port around the casing. At this time, since the temperature sensor is sandwiched between the laser diode and the thermoelectric cooler, the effect of heat received from air flowing around the inside of the housing is effectively reduced.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.
4 through FIG.

FIG. 1A is a plan sectional view, and FIG. 1B is a front sectional view. The PDT laser device shown in FIG. 1B has a laser diode 1 that outputs an excitation laser.
(Abbreviated as LD in the drawing), an electronic cooling element 2 for changing the wavelength of the output laser by heating and cooling the laser diode 1, a temperature sensor 3 for detecting the temperature of the laser diode 1, and a temperature sensor 3 A temperature controller 4 as a control unit for controlling the heat exchange by the electronic cooling element 2 based on the output of the electronic cooling element 2 and controlling the wavelength of the laser to a predetermined constant wavelength is provided in the housing 5. Especially,
The temperature sensor 3 includes a laser diode 1 and an electronic cooling element 2
In this state, the laser diode 1 and the thermoelectric cooler 2 are provided close to each other. Also,
An intake port 6 and an exhaust port 7 capable of forcibly ventilating the air in the housing 5 are provided on the housing surface.

More specifically, in the present embodiment, the laser diode 1 outputs a laser having a wavelength corresponding to the temperature of the main body in response to an external signal. This output laser is guided to the outside of the housing 5 through an optical fiber (not shown). The unit of the laser diode 1 is in contact with the upper part of the U-shaped jig 8 and is screwed. The jig 8 is formed by connecting two side plates and one top plate to form a U-shape. One end of each side plate is in contact with the bottom surface of the housing 5 and the jig 8 is connected to the top plate and the housing 5. The side faces are connected by two L-shaped members 9, 9. These two L-shaped members 9 and 9 are fixed to the top plate of the jig 8 and the side surface of the housing 5 by screws.

Inside the jig 8, in order from the side closer to the laser diode 1, an electronic cooling element 2, a fin 2 a for increasing the heat exchange efficiency by the electronic cooling element 2, and an intake air to the fin 2 a. And a fan 2b for performing the operation. The electronic cooling element 2 is a Peltier element, for example, and is fixed in contact with the top plate of the jig 8.

For this purpose, the temperature sensor 3 is embedded in the top plate of the jig 8. FIG. 2 is a cross-sectional view showing a state where the temperature sensor 3 is mounted. The top plate 8a of the jig 8 has a thickness of 1
The temperature sensor 3 is embedded in the concave portion. The concave portion is formed on the surface that comes into contact with the unit of the laser diode 1, and after applying the thermal conductive grease inside the concave portion, the temperature sensor 3 is embedded, and further, the thermal conductive grease is applied to the contact surface with the laser diode 1. The laser diode 1 is closely attached. Thus, the temperature sensor 3
To prevent air from entering the surrounding area, ensuring high thermal conductivity. Here, the temperature sensor 3 is disposed substantially at the center of the unit of the laser diode 1 as shown in the plan view of FIG. Here, in the prototype, aluminum was adopted as the material of the jig 8, and a platinum resistance element having a diameter of about 2 mm was selected as the temperature sensor 3. Also,
Temperature sensor 3 by shaving about 2 mm using a 5 mm thick top plate
Embedded.

The housing 5 containing these elements is actually used with a lid (not shown in FIG. 1) attached.
The intake port 6 is arranged at a position facing the fan 2 b mounted inside the jig 8. In addition, the exhaust port 7 is shown in FIG.
As shown in (b), it is arranged at a position corresponding to the attachment position of the jig 8 on the back surface of the housing 5. In particular, the exhaust port 7 is arranged at the upper part of the housing 5 (almost at the same height as the unit of the laser diode 1) to prevent the inconvenience of warm air staying at the upper part of the housing 5. here,
Reference numeral 15 denotes a leg of the housing 5, and the function of the leg makes it possible to easily perform intake from the intake port. Reference numeral 11 denotes an LD driver for driving the laser diode 1.

Next, FIG. 3 shows a configuration diagram of an electric system including the LD driver 11. The electrical system shown in FIG.
An LD driver 11 for driving the laser diode 1; a hybrid recorder 12 as a storage unit for sequentially recording output values of the temperature sensor 3; and a temperature sensor, in addition to the laser diode 1, the thermoelectric cooler 2, and the temperature sensor 3 described above. 3
A temperature controller 4 for controlling heat exchange in the electronic cooling element 2 based on the output of the main cooling unit 2, a main control unit 13 for controlling the operation of these units, and an input unit 14 for instructing the main control unit 13 to perform an operation. Equipped. Here, the hybrid recorder 12 is not shown in FIG.
It may be provided in the housing 5 or may be arranged outside the housing.

Among them, the temperature controller 4 is preset with an optimum temperature as the temperature of the laser diode. This optimum temperature is the temperature of the laser diode 1 when the laser diode outputs a laser having a wavelength suitable for the absorption wavelength of the photosensitizer (photosensitive substance) injected into the patient's body (hereinafter referred to as the laser diode 1). , Target temperature). Then, the temperature controller 4 controls heat exchange by the electronic cooling element 2 so that the output of the temperature sensor 3 converges to the target temperature. When the thermoelectric cooler 2 is a Peltier device, the temperature controller 4 heats or cools the laser diode 1 by appropriately switching the polarity of the drive current of the Peltier device.

The input section 14 has means for setting the laser output time, a first switch for starting the laser output, a second switch for enabling the first switch, and a stop for the laser output. Is performed automatically by a timer or the first
And a changeover switch for switching whether to perform the operation manually with the above switch. The main controller 13 operates based on these input operations.

Next, the laser output preparation operation in the above embodiment will be described.

When the power of the apparatus is turned on, the fan 7a of the exhaust port 7 is started, and outside air is introduced from the intake port 6.
The taken outside air flows through the inside of the housing 5 and passes through the exhaust port 7 to the outside. Thereby, ventilation in the housing 5 is performed. Further, the fan 2b inside the jig 8 is also started, and the outside air taken in from the intake port 6 flows to the fin 2a. Furthermore,
The electronic cooling element 2 is also started, and heat exchange between the fin 2a and the laser diode 1 is started. Here, the subsequent operation will be described assuming that the temperature of the laser diode 1 is higher than the target temperature.

First, the temperature of the laser diode 1 is detected by the temperature sensor 3 and input to the temperature controller 4. The temperature controller 4 determines that the input temperature is higher than the target temperature, and drives the electronic cooling element 2 in a direction to cool the laser diode 1. At this time, heat exchange is promoted by the outside air passing through the fins 2a. The heated outside air is discharged from the exhaust port 7 to the outside. On the other hand, when the temperature of the laser diode 1 becomes lower than the target temperature, the reverse control is performed. Then, after the temperature of the laser diode 1 has converged to the target temperature, the laser diode 1 is driven. As a result, the photosensitizer injected into the body of the patient is efficiently excited.

When performing PDT, the operator sets the changeover switch of the input section to "automatic" and sets the laser output time. Then, when the first switch is turned on after the second switch is turned on to enable the first switch, the LD driver 11 is driven by the main control unit 13 and the laser output is started. According to this, since the output of the laser is not started just by turning on the first switch, a situation in which the laser is output due to an erroneous operation can be prevented. When a preset laser output time has elapsed since the laser was output, the operation of the LD driver 11 is stopped by the main control unit 13, and the laser output is cut off.

On the other hand, when the operator tries the laser output for a short time, the changeover switch is set to "manual". Then, the first switch is turned on and immediately turned off. Thus, the main control unit 13 outputs the laser only for a moment while the first switch is on.

According to the above-described embodiment, the temperature sensor 3 is connected between the unit of the laser diode 1 and the thermoelectric cooler 2, more specifically, the top plate 8 a of the jig 8 and the laser diode 1. Because it is enclosed between the unit,
The outside air heated (or deprived of heat) by the fins 2a does not affect the temperature detection of the temperature sensor 3 as a disturbance, and the temperature of the laser diode 1 can be controlled to the target temperature with high accuracy. It is possible to reliably output the laser wavelength at a desired wavelength.

Further, the temperature sensor 3
Embedded, the laser diode 1 and the thermoelectric cooler 2 can be mounted closer to each other, thereby improving the heat transfer efficiency and quickly controlling the temperature of the laser diode 1 to the target temperature. be able to. Further, since the temperature sensor 3 is provided by shaving the laser diode 1 side of the top plate of the jig 8, the temperature sensor 3 is disposed closer to the laser diode 1 side than the electronic cooling element 2 in the attached state, and the temperature of the laser diode 1 is reduced. Can be detected with higher accuracy. In addition, since heat conductive grease is applied around the temperature sensor 3 and the unit of the laser diode 1 is provided in close contact with the temperature sensor 3, the heat transfer efficiency can be further improved, and the temperature to the target temperature can be more quickly increased. Control can be realized, and at the same time, temperature detection of the laser diode 1 by the temperature sensor 3 can be performed with high sensitivity.

[0023]

Since the present invention is constructed and functions as described above, according to this, the laser diode and the electronic cooling element are brought close to each other with the temperature sensor arranged between the laser diode and the electronic cooling element. Since it is equipped, the inconvenience of external air receiving (or passing) heat from the electronic cooling element affecting the temperature detection of the temperature sensor as a disturbance can be suppressed, and the temperature of the laser diode can be accurately adjusted to the target temperature. Therefore, it is possible to provide an unprecedented excellent PDT laser device capable of more reliably outputting the wavelength of the excitation laser at a desired wavelength.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a physical configuration according to an embodiment of the present invention, in which (a) is a plan view and (b) is a front view.

FIG. 2 is an enlarged view of a main part for explaining a mounting state of the temperature sensor of FIG. 1;

FIG. 3 is a block diagram showing an electrical configuration of an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laser diode 2 Electro-cooling element 3 Temperature sensor 4 Temperature controller (control part) 5 Housing 6 Intake port 7 Exhaust port

Claims (1)

[Claims] 1. A laser diode for outputting an excitation laser, an electronic cooling element for changing the wavelength of an output laser by heating and cooling the laser diode, a temperature sensor for detecting the temperature of the laser diode, A PDT laser device equipped in a housing with a control unit for controlling heat exchange by the thermoelectric cooler based on the output of the sensor and controlling the wavelength of the laser to a predetermined constant wavelength, wherein the temperature sensor is connected to the laser diode The laser diode and the electronic cooling element are provided in proximity to each other in a state where the laser diode and the electronic cooling element are arranged between the housing and the electronic cooling element. Characteristic laser device for PDT.