The features of chart of the stationary laser scanning therapeutic apparatus (ALS) of invisible (infra-red) radiations for the outward irradiation are determined by the following properties:

Necessity of the multidirectional positioning of laser instrument in relation to the area of therapeutic influence due to the ALS motion (adaptations), hinge manipulator, and optical deflector;

Complication of positioning and control of position of working infra-red beam;

Complicated character of emittance of semiconductor IR-lasers, pulsed mode of radiations of several types of semiconductor lasers;

Limited possibility of the use of focusing diffraction elements defined by the wide spectral line of radiations of semiconductor lasers (up to 100 nm);

Necessity of the use of complicated trajectory of laser beam scanning;

Difficulty of the calculation of optical elements with the use of the standard programs, without taking into account chromatic aberrations;

Necessity of the use of complicated technologies and materials for making of optical details.

Thus, stationary laser scanning therapeutic apparatus (ALS) of invisible (infra-red) radiations for the outward irradiation is the device based onto therapeutic influence of laser infra-red radiations with a wave-length of λ = 0,8...0,9 µm at medical treatment of diseases in gastroenterology, neurology, dermatology, traumatology, orthopedy and other. The features of design and application of ALS of this type, set above, demanded of development, research and adaptation of a few new subsystems and blocks. In particular, TV-system of visualization of infra-red image of laser ray, able simultaneously to pickup and display of the images of biological tissue in the visible range of spectrum is developed, and optical system of formation of thin optical infrared laser beam and block of concordance of frequency parameters of optical deflector with frequency parameters of pulsed laser was also created.

A general chart and the ALS arrangement are represented on the fig.33.

Structurally apparatus includes a small moving table 10, on which the iterative joint manipulator MAN is mounted with the block of emitter 1, optical deflector 3 and television system of visualization of infra-red image 6, 7, and also programmable control block 11 with a control stand and video-monitor 12, fastened on a table. The links of the manipulator MAN1, MAN2, MAN3, MAN4 and MAN5 allow adapting an optical ray and component parts of apparatus according to the position of patient body.

The structural elements listed above are executed as follows. In the corps of emitter block a laser diode 1 and forming lens 2 are placed. This lens consists of a few anamorphous lenses clarified for the near infra-red region of spectrum. The laser diode 1 is fixed in a mobile hob. Lens 2 is set in a corps motionlessly. As a scanning device a two-coordinate optical deflector 3 is used.

The optical chart of apparatus includes a laser diode 1, focusing lens 2, deflector 3 with turning mirrors 4 and 5, television block with a forming lens 7, CCD- matrix 6 and video-monitor 12. The infra-red laser radiations marked by the wave vector k_IR and ambient radiations marked by the wave vector k_amb, fall onto the biological object 9. Accordingly the infra-red radiations and visible ambient radiations reflected from the biological object 8 act onto the system of image pickup. Optical elements of focusing lens 2 are clarified for a wave-length λ = 0,82 µm. Mirrors 4 and 5 of optical deflector for this wave-length have maximal value of reflection coefficient.

A programmable control block (PCB) consists of four functional blocks (fig.34): power supply 13, microcontroller 14, digital-to-analog transformer (DAT) 29, and television block 16. Microcontroller 39 together with video-monitor 6 and control stand represent microcomputer 12. The power supply module 13 includes laser power supply and PCB power supply. The basic elements of DAT are the next: timer 15, electronic adapters 16 and 17, sinusoidal signal formation modules 18 and 19, output transformers 20 and 21, electronic regulators of amplitude 22 and 23, power amplifiers 24 and 25, and modulator 26.

The television block 16 consists of lens 8, CCD- matrice 7, preliminary amplifier 27, block of television channel control 28.

The apparatus described above works as follows. The emitter block of and television block 16 are set in the working area of biological object. The power supply module 13 provides necessary feeds onto the functional blocks of scanning device. By the keys of control stand 12 laser emitter 1, video-monitor 6 and television block 16 are activated. By the turns of manipulator and deflector 11 field of view of television block 16 is coincided with the beam of emitter on the surface of the biological object 9. The lens 2 forms the small size spot of radiations on the surface of the exposed tissue. The laser infra-red beam formed by a lens 2 gets onto optical deflector 11 (SCAN), which carries out one-coordinate or two-coordinate scanning due to mirrors 3 and 4, moving in bearing by the electromagnets 33. The lens 8 of television block pickup the images of object and trajectory of scanning laser ray 10 onto the sensible CCD-matrix 7.

Video-signal from a CCD-matrix is amplified by a preliminary amplifier 27, passes onto the control block 28 of a television channel 16, and is transformed into a television signal, forming the television image of biological object and of infra-red radiation spot on a video-monitor 6.

Scanning device works in two modes – of visualizations and control. Switching of the modes is produced by the keys of control stand. In the mode of visualization a television block is activated, and the image of object and of scanning laser ray appears on the screen of video-monitor 6. In the control mode the control parameters of laser scanning device are displayed on a video-monitor. In apparatus a possibility of combination of the modes of visualization and control is foreseen. In this case the image of the object exposed by a scanning laser ray and table of parameters of control are simultaneously displayed on the screen of video-monitor 12.

A programmable block executes control of the modes of operations of scanning device by means of control stand 12.  It also control of the mode of visualization of parameters on the screen of video-monitor 6. The power supply module 13 provides necessary DC electrical feed to microcontroller 14, digital-to-analog transformer and television block 16. The module also feeds laser emitter 1 and video-monitor 6.

Microcontroller 14 executes the functions of microcomputer, having necessary ROM that determines high operative control of laser scanning device. The central processor of microcontroller 14 provides arithmetic and logical processing of information in accordance with the program. The program sets a sequence and duration of the modes of operations, form of scanning figure and trajectory of its motion on the surface of biotissue. It also determines character and movement velocity of laser ray or figure.

A digital-to-analog transformer forms analog (sinusoidal) signals of control and transmits it on the two independent channels of the electromagnetic mirror drives of optical deflector 11 in accordance with the digital information got from microcontroller 14.

The timer 15 works in the mode of delivery of continuous pulse string on two channels with changeable frequency of the following of pulses in every channel. Sinusoidal signals formation modules 18 and 19 through output transformers 20 and 21 and electronic regulators of amplitude of sinusoidal signals 22 and 23, limiting its level in accordance with the digital code of the electronic adapters 16 and 17 give the control signals onto the power amplifiers 24 and 25. These blocks amplify signals to the values necessary for control of optical deflector 11.  Modulator 26 changes frequency of the laser radiation pulses following. Regulation of laser radiation power is produced by the change of value of the feeding current given onto the laser diode 1. Parameters of modulation, power of laser radiation, and also parameters of scanning are set by the keys of control stand 12 and controlled on a video-monitor 6.

References:

1.       Sidorov V.I. Laser Scanning Medical Apparatus (ALS) for Surgery and Therapy.

2.       Rebrin Y.K., Sidorov V.I. Optical Deflectors. Kiev: Tékhnika, 1988. - 136 pp.

3.      Rebrin Y.K., Sidorov V.I. Optical mechanical and holographic deflectors // Results in science and technology. Radio engineering. Vol. 45. - Moscow: VINITI, 1992. - 252 pp.

4.       Rebrin Y.K., Sidorov V.I. Holographic units of control of an optical ray. – Kiev:  KHMAES, 1986. -  124 pp.

5.       Rebrin Y.K., Sidorov V.I. Piezoelectric multielement units of control of an optical ray. – Kiev:  KHMAES, 1987. - 104 pp.

Vasil Sidorov on February 06, 2011 in queltanews.com

Technopark QUELTA,

Nizhyn Laboratories of Scanning Devices

sidorovvasil@gmail.com