In the animation, as opposed to a real micrometer, we only do readings of the distance to the nearest hundredth of a millimeter.

nd:yaglaserfor skin

A micrometer allows a measurement of the size of a body. It is one of the most accurate mechanical devices in common use. This document introduces this instrument.

Depending on your eyes and the particular micrometer that you use, assigning a Reading Error of ± 0.003 mm is probably reasonable. This is 3 micro-meters!

Patient’s satisfaction: 1 = not satisfied, 2 = little satisfied, 3 = somewhat satisfied, 4 = satisfied, 5 = very satisfied.

Nd YAG laserfor pigmentation

There is a clear demand for laser treatment of various vascular lesions, but there are still challenges when using laser energy in a therapeutic context. PDL and IPL are used to treat superficial vascular lesions, but are not ideal for treating deeper lesions.3 With the advent of lasers with longer pulse durations and wavelengths than those used for PDL and IPL, deeper and larger caliber vessels can be managed more effectively without frequent treatment sessions and side effects. Long-pulsed Nd:YAG laser treatment of deeper vessels has been shown to be effective; however, the long-term effects of this laser treatment have not been evaluated.4 In this study, we demonstrated that diverse vascular lesions responded favorably to long-pulsed Nd:YAG laser therapy. As expected, we found that selective photothermolysis of vessels in vascular disorders including erythema, telangiectasia, port wine stain, cherry angioma, and hemangioma could be achieved by 1064 nm Nd:YAG laser pulses. Both PGA scores and patient satisfaction ratings after laser treatment were good. Long-pulsed Nd:YAG laser therapy can therefore potentially be used to treat both superficial and deep vascular disorders.

With regard to side-effects, higher risk of potential collateral damage around vessels and pain during the procedure should be kept in mind when using this laser for vessels.2 Water, a competing chromophore of light at the wavelength of 1064 nm, may be the culprit responsible for additional tissue damage despite the fact that this wavelength is absorbed 10-fold more by oxyhemoglobin than water.2 In our study, all patients tolerated the procedure moderately well without remarkable pain. Two patients experienced postinflammatory hyperpigmentation on the site of the vesicles; this epidermal damage may have been caused by the high fluence. Technically, a non-overlapping technique is very important to avoid subsequent complications like scar formation.15 When we performed laser therapy to treat telangiectatic vessels, we evaluated the therapeutic end point based on the immediate response of the vessels. However, when treating diffuse erythema rather than telangiectasia, clinicians should be cautious when selecting parameters; however, guidelines to reduce adverse reactions have yet to be established.

This study had several limitations. First, we included only a small number of patients. Second, this was not a randomized controlled study and we did not directly compare the long-pulsed Nd:YAG laser with PDL and IPL. Third, long-term follow-up was not performed.

Nd:YAGlaserfrequency

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Nevertheless, we demonstrated that long-pulsed Nd:YAG laser treatment is an alternative treatment modality for various vascular problems recalcitrant to standard therapy. Our study could also contribute to the establishment of appropriate treatment parameters. It is important to note that the use of bulk skin cooling, no overlapping of pulses, use of subpurpuric fluences, and use of a small spot size can limit dermal injury and improve the safety of Nd:YAG lasers. Further studies comparing the effects of variations in each of the treatment parameters or different treatment intervals should be performed to determine optimal treatment conditions.

The above diagram shows a micrometer measuring the width of a pencil. The Thimble is rotated, causing it to move right or left. It is connected to the right-hand Measuring Rod, which also moves right or left. The measured size of the pencil is the distance between the two measuring rods when they are just in contact with the sides of the pencil.

This document, including all figures and animations, was written by David M. Harrison, Dept. of Physics, Univ. of Toronto, mailto:harrison@physics.utoronto.ca in August 2002.

Fourteen Korean patients underwent a single treatment session using a long-pulsed Nd:YAG laser. Two blinded clinicians rated cosmetic outcomes using ‘Physician Global Assessment (PGA)’ based on standardized photographs. Patients’ subjective satisfaction and side-effects of treatment were evaluated after treatment.

The diagram to the right is a close-up of the micrometer showing the thimble. The thimble rotates around a cylinder which has markings every one-half millimeter.

Now the distance between the measuring rods is 7.500 mm. The downward line on the cylinder corresponding to 7.5 mm is barely visible.

The most common side effects were erythema and vesicles in four of 14 patients (28.6%). Among these four patients, two reported mild post-inflammatory hyperpigmentation on the side that they received long-pulsed Nd:YAG laser treatment. However, those cutaneous reactions showed improvement without scarring (Fig. 3). No unbearable pain was noted in this study, and all patients tolerated the treatment well.

A 1064 nm long-pulsed neodymium:yttrium-aluminum-garnet (Nd:YAG) laser has been proven to be effective for the treatment of leg veins because of its deep penetration into the skin and homogenous heating of large vessel walls.2 Recently, the efficacy of long-pulsed Nd:YAG laser treatment for various vascular disorders such as port wine stain, hemangioma, angiokeratoma, and venous lake was reported.5,6

Nd:YAGlaserbefore and after

You should always use the Friction Screw or its equivalent to close the rods on an object. Otherwise incorrect measurements will result!

Long-pulsed Nd:YAG laser treatment is a safe and effective treatment modality for diverse vascular disorders that are unresponsive to conventional therapy.

There are several possible causes for the steep fluence-response curve of Nd:YAG laser treatment. When blood is heated to 50–54°C, partial oxidation of oxyhemoglobin leads to met-hemoglobin (met-Hb) formation.7,10 Optical absorption by met-Hb is much higher than that of either Hb or hemoglobin.11,12 Several in vitro studies13,14 have demonstrated that when blood is photocoagulated by 1064 nm Nd:YAG laser pulses, absorption at 1064 nm increases on the millisecond time scale by a factor of about 3, which may be due to partial conversion of oxyhemoglobin to met-Hb. When the lumen is thermally coagulated, optical scattering is increased and formation of a coagulum results in concentration of chromophores.1 In summary, long-pulsed Nd:YAG laser irradiation can heat up the entire vessel wall and coagulate the vessel at high fluence, which aids in the clearance of vascular lesions, unlike PDL and IPL.

In this retrospective study, we identified 16 patients with cutaneous vascular disorders who visited the dermatology clinic of Hanyang University Hospital between June 2014 and May 2015. All patients were of Fitzpatrick skin types III and IV. Patients for whom standardized photographs were obtained before and after treatment were considered eligible for inclusion. Patients with a history of deep vein thrombosis, connective tissue disease, predisposition to hypertrophic scars and keloids, oral isotretinoin in the previous 2 months or immunosuppression, or who were pregnant or lactating were excluded.

Five men and nine women were finally enrolled (mean age 45.4 ± 16.4 years) in this study. Thirteen of 14 patients (92.9%) had good or excellent PGA results. Ten of 14 patients were very satisfied or satisfied with the clinical results (71.4%), and all patients reported that immediate treatment discomfort was tolerable. Side effects were minimal; four patients (28.6%) reported erythema, vesicles, or hyperpigmentation which recovered without scarring.

If you are a student in the Physics laboratory at the University of Toronto, the material discussed here is also covered in the Commonly Used Instruments section of the First Year Laboratory Manual. There is also a videotape on using a Micrometer and a Vernier Caliper available from the laboratory technologists.

In this case, then, the distance between the measuring rods is 7.000 mm. The upward line on the cylinder corresponding to 7 mm is barely visible under the thimble.

Note that this is all consistent with the fact that the markings on the cylinder correspond to fifty divisions for a complete revolution. Thus the numbers on the thimble correspond to hundredths of a millimeter.

All patients underwent a single treatment session using a long-pulsed Nd:YAG (Multiflex, Ellipse A/S®, Denmark). Surface cooling was achieved using a focused stream of cool air (SoftCoolTM) to reduce pain during treatment and to minimize the risk of possible epidermal damage. To treat vessels with a diameter of 0.2–0.3 mm, the following treatment parameters were used: 12.0 ms pulse width and 214.2–260.3 J/cm2 of fluence using a 1.5 mm spot. Larger dilated vessels with a diameter of 0.3–0.5 mm were treated with a pulse width of 16.0 ms and 225.1–252.2 J/cm2 of fluence using a 3.0 mm spot. When the vessel was treated with the laser, the immediate vessel response was carefully tracked. If the vessel disappeared immediately, the next laser shot was applied at the point where the vanishing point stopped. If the vessel did not show any response after the first shot, the fluence was raised to the next level (10–20 J/cm2 higher in general) and the laser firing point was moved up by about 1–2 mm from the initial spot to avoid stacking of laser pulses.

Among the lasers for vascular lesions, the ratio of melanin to blood absorption is similar at 585 and 1064 nm, whereas the absolute values of absorption and scattering coefficients are considerably lower at 1064 nm as compared with 585 nm.7,8 It might imply that 1064 nm pulses can treat deeper vessels selectively. Lower absolute values of blood absorption at 1064 nm can be compensated for by increasing the fluence. Although a very high fluence of more than 150 J/cm2 must be applied, this increase in treatment fluence does not necessarily damage the epidermis, because the absolute absorption of melanin is lower at 1064 nm as well.4 In addition, the absorption coefficient of blood at 1064 nm is 0.4/mm, which is much higher than that of the surrounding dermis (0.05/mm) at the same wavelength. This difference in absorption coefficients makes 1064 nm light more selective for treatment of deep blood vessels than shorter wavelengths of light.8,9

1064 Nd YAG laserprice

This material may be distributed only subject to the terms and conditions set forth in the Open Content License, v1.0 or later (the latest version is presently available at http://opencontent.org/opl.shtml).

nd:yaglaserfor skin whitening

Seven of 14 patients (50%) showed excellent improvement, six patients (42.9%) showed good improvement, and one patient (7.1%) showed moderate improvement. The average PGA score was 2.43 (Table 1, Figs. 1, 2).

Several lasers emitting in the green and yellow range of the light spectrum, such as 585 nm and 595 nm pulsed dye lasers (PDLs), the 532 nm KTP laser, and the 578 nm copper vapor laser, are standardly used to treat various vascular disorders including port wine stains, superficial hemangioma, and telangiectasia.1,2 Intense pulsed light (IPL)-emitting noncoherent broadband light is considered to be an effective treatment option for diverse vascular lesions.3 However, this treatment modality tends to be less effective for deeply-situated vascular lesions than superficial vascular lesions due to the limited penetration depth of light.4

There is an animation of reading the micrometer. You may access the animation by clicking on the red button to the right. It will appear in a separate window, and has a file size of 31k.

1064-nmlaserskin treatment

Depending on your eyes and screen resolution, you might be fairly confident that the reading is less than, say, 8.627 mm and similarly confident that it is greater than 8.621 mm. Thus you might assign a Reading Error to this measurement of 0.003 mm

Long-pulsed neodymium:yttrium-aluminum-garnet (Nd:YAG) lasers have recently been used for treatment of large, deep vascular lesions refractory to conventional vascular lasers. The aim of this study was to evaluate the clinical efficacy and safety of long-pulsed Nd:YAG laser treatment of various vascular disorders.

Because of the mechanical advantage due to the fine pitch of the screw threads that move the thimble and the right-hand measuring rod, it is easy to use enough force in closing the rods on the object being measured to deform either the rods or the object. In the diagram you can see a Friction Screw, which applies "just enough" torque to rotate the thimble in a gentle manner.

Among 16 enrolled patients, two patients dropped out for personal reasons unrelated to the treatment. The remaining 14 patients completed this study. Patients’ age ranged from 16 to 62 years (mean, 45.4 years). Subtypes of vascular disorders were facial telangiectasia, rosacea, port wine stain, hemangioma, cherry angioma, and acne erythema. Detailed demographic information is provided in Table 1.

Clinical assessment was done by two blinded clinicians using Physician Global Assessment (PGA) based on evaluation of pre-treatment photographs and post-treatment photographs taken 1 month after the last treatment. Improvement was assessed on a scale from 0 to 3 (0 = no improvement, 1 = moderate, 2 = good, 3 = excellent). In addition, patients were asked to rate their satisfaction with the cosmetic results (1 = not satisfied, 2 = a little satisfied, 3 = somewhat satisfied, 4 = satisfied, 5 = very satisfied). Side effects after treatment were also assessed.

Patients were generally satisfied with the cosmetic outcomes of their treatment. Mean score was 4.0, and 10 of 14 patients stated that they were ‘very satisfied’ or ‘satisfied’ with their appearance. The boxes of ‘somewhat satisfied’ and ‘little satisfied’ were checked by one of the patients who experienced adverse effects (Table 1).

The left-hand side of the thimble has markings all around it. The line labelled 0 is the primary pointer. When it lines up with the central horizontal line on the cylinder, as shown, then the distance between the measuring rods is exactly an integral or half-integral number of millimeters.

Now the distance is greater than 8.620 mm, but clearly less than 8.630 mm. We might estimate this reading to be 8.624 mm.

In this study, we investigated the clinical efficacy, side effects, and subjective satisfaction of Korean patients after they underwent long-pulsed Nd:YAG laser treatment for diverse vascular disorders.

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