6. Medical Capabilities of the Crystal 2000 Family Laser Devices

A.A.Radaev

An analysis of our previous developments showed us their pros and cons. To extend medical capabilities of our laser systems, we developed the Crystal 2000 family. These devices produce laser radiation, which comes from several diodes. This radiation is coupled into several hair-like light-guiding fibers. After that, these fibers integrate into a single light-guiding fiber of a diameter of 400 to 800 µm. Fig.1 shows a typical Crystal 2000 laser diode device.

Fig.1. The Crystal 2000 laser diode device

We produce a wide range of these devices (see the Table).

Table. The Crystal 2000 laser diode devices (their wavelength, nm, and maximum cw radiation power, W, are shown in brackets)

It can be seen from the Table that the Crystal 2000 devices can be applied with success in laser therapy, laser surgery, laser cosmetology, photodynamic therapy, and laser thermal destruction. In fact, all these devices embody a similar principle. Due to a high unification degree, the manufacturing cost of these devices is substantially reduced. Furthermore, the high unification degree simplifies the operation of different devices. This also expedites the creation of special-purpose devices. In the latter case, two devices differ solely in the set of built-in lasers. Fig.2 shows a typical layout of laser diodes in a heat chamber.

Fig.2. A typical layout of laser diodes in a heat chamber

Fig.3 shows the device’s functional diagram.

Fig.3. The Crystal 2000 functional diagram: (1) ventdoors, (2) ventilators, (3) thermal cooler,

(4) cooler circuit, and (5) heat chamber for lasers

This layout yielded a high therapeutic efficiency in laser medicine. Below, we shall outline the device’s features.

Careful investigations were performed with a smaller number of ventilators, without input and output ventilators, as well as without both pre-cooling in the mainframe and final cooling in the thermostat. The results obtained showed that the temperature of operating lasers cannot be stabilized in these cases. When switched on, lasers cannot be cooled instantaneously down to a necessary temperature. Because of this, the lasers are not turned on immediately after the power-up. They are energized no sooner than the heat-stabilized circuit with lasers has reached a necessary temperature. A system of this type maintains the temperature of operating laser diodes to an accuracy of ± 0.1 °C. In this case, the power consumption is not more than 60 W. The READY signal tells the physician that the thermostat is ready.

We also studied other heat-stabilization patterns, which are simpler than the above-described one. However, they all produced considerable temperature variations, which finally put lasers out of order. We tested our devices in a temperature range of +12 to +35 °C. The results obtained showed that the devices functioned normally. Because of this, the Crystal 2000 devices can be run in medical establishments without air-conditioners. Heat stabilization is one of the ways to increase the devices’ reliability. Another way is to introduce a special circuit to diagnose the supply line. The point is that the supply-line voltage can differ from the nominal one (220 V, 50 Hz). For example, the supply-line voltage in hospitals and polyclinics can be substantially different. The voltage can also differ from that given in the State Standard. This may lead to the degradation of laser diodes. To protect operating rooms from voltage variations is a very expensive and intricate problem. It requires a large and costly stabilizing system. Our device switches off in the case of power-supply jumps. This approach makes it possible to considerably reduce the device’s cost and dimensions. It also secures laser diodes from overloads, which ensures high performance reliability. Because of this, our devices have a long warranty lifetime.

Let us point out a distinguishing feature of our device delivery. The device comes with a Certificate for American Laser Diodes, which are used in the device. These diodes are the best laser diodes all over the world. They produce optical radiation of a fixed wavelength and power. As a result, the physician knows exactly the radiation wavelength and maximum power of the entire device, allowed for losses. The output power at the fiber’s end should not exceed the maximum total power of lasers with due account of 30 % losses in the channel. Otherwise, a manufacturer has set laser diodes in an overrun mode. This may lead to a soon degradation of laser diodes. Today, medical devices of this class cannot be cheap. The point is that these devices use laser diodes that operate under high-power conditions. As a result, when devices employ poor-quality laser diodes, they degrade soon. However, the customer can easily ferret out the best manufacturer of laser diodes and the real cost of the entire device. The device’s maximum power depends on the number of installed modules, whereas its output wavelength comes from the certificate for laser diodes. Note, the manufacturing cost of 635-nm laser diodes now exceeds that of 662-nm laser diodes tenfold. However, 635-nm laser diodes produce a different clinical effect, for example, in photodynamic therapy. As a result, the physician can easily predict a possible clinical effect by studying the certificate for laser diodes. Besides that, the physician can check the power and wavelength of the entire device using special-purpose instrumentation. However, such instrumentation is scarce and almost inaccessible to medical practitioners. It follows from the certificate that the wavelength variation is not more than 10 nm.

In the beginning of this article, we showed our stock-produced devices. However, a customer can order any device operating in the range of 635 to 1060 nm. Such laser devices can be produced in two ways. In the first one, the manufacturer takes separate lasers and couples their radiation into a single output fiber. This can be done by means of hair-like fibers. In the second way, the manufacturer purchases integrated laser modules. Their radiation has already been coupled into a single fiber by the firm-manufacturer. We employ the first, more labor-consuming, way because it offers essential advantages. First, it provides a better heat abstraction, without an additional thermistor between the module and heat chamber. Secondly, our laser diodes are not closely spaced (as in the case of laser modules). This also considerably improves heat abstraction to the heat chamber. Thirdly, the wavelength range of laser diodes is much wider than that of laser modules. This makes it possible to more fully satisfy the customer’s requirements. Fourthly, we can install any number of laser diodes emitting at any wavelength. As a result, our devices can produce not only fixed powers of 5 W and 10 W, but also intermediate powers of 1, 1.5, 2 to 5, and 7.5 to 10 W. In turn, this offers additional advantages. For example, we can easily make the Crystal 2000 device with a maximum power of 0.5 W and seven operating wavelengths: 635, 662, 675, 780, 810, 980, and 1060 nm. Note, such a device cannot be produced from ready-made laser modules. Different wavelengths and powers can be used within the framework of impeccable functioning of a heat stabilizer. If needed, a customer can order a device operating at several wavelengths. By specifying a requisite radiation power, the customer can trade off cost against quality, which is impossible in the second way.

While the device is in use, its maximum power can be increased on the customer’s demand. Such a modification is performed at the minimum price and at the earliest possible date. To this end, additional lasers are installed into the device. In this case, laser radiation from new and old laser diodes is then coupled into a common fiber. At the minimum price, a single high-power device can also be separated into two devices producing the same total power. For example, we performed an “operation” on a 15-W laser and produced from it two lasers emitting at powers of 6 and 9 W.

If physicians need to replenish their knowledge of laser medicine in any lead, we provide special training. After the training, the physicians are granted with a certificate.

The device is designed as a lightweight (4 kg) and portable (290 x 210 x 240 mm) monoblock. If needed, a person can easily carry the device, both indoors and outdoors. As a result, a physician can utilize the potentialities of this device to the best advantage. It is worth noting that almost no-one claimed a warranty or post-warranty repair. The oldest two devices have been in clinical practice for 30months. The continuous operating time of these devices has exceeded 750 hours. Nevertheless, if a failure occurs, we shall quickly and reliably do a warranty or post-warranty repair in Moscow.

The customer will never be faced with tool problems. This is because our device comes with three operating fibers. If needed, we can supply any type of light-guiding fibers compatible with the SMA-905 joints. Now, many manufacturers produce instruments compatible with the joint of this type. Besides that, our device can come with any necessary equipment and consumed materials. They are supplied at an additional price. Note, all the equipment is guaranteed for compliance with the International Electro-Technical Commission Standards (i.e., it does no damage to the supply line). This is, undoubtedly, of great importance because some operating rooms have an ideal supply line. Such a line is created using a number of engineering solutions. It is a real disaster when a single device wrecks the line completely. Our device will never cause such a disaster. Hence, as manufactures, we undertake additional obligations to enjoy physicians’ confidence and improve their work.

The proposed layout of the Crystal 2000 device makes it possible to successfully apply this device in laser therapy, photodynamic therapy, laser surgery, cosmetology, and laser thermal destruction. In addition, it provides physicians with comfortable operational conditions.