LASER PHYSICS SLIDE 9-20 BY AJ OF VMS BIOMEDICAL — Transcript

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1. 0:01This next topic that we will be
2. 0:03discussing is laser parameters
3. 0:06and this is what we adjust on your
4. 0:09laser.
5. 0:12These are the most most common ones
6. 0:14found in any laser system and as such I
7. 0:17expect all of you to get familiarized
8. 0:19with them as each of these will impact
9. 0:24your treatments.
10. 0:28So the first parameter which we
11. 0:30typically adjust
12. 0:33is the energy or we also call it power
13. 0:36or fluence.
14. 0:38There are two units. Your lasers
15. 0:41probably designed with watts
16. 0:45which in simple terms it's how fast the
17. 0:47light travels.
18. 0:50And we have the jewels.
19. 0:52The jewels
20. 0:55talks about the speed of light
21. 0:58in relation to time. So there's a
22. 1:01formula for this. It's watts
23. 1:05time second equals jewels.
24. 1:09And jewels typically refer to a specific
25. 1:13square area of your target.
26. 1:18Now let's speak about the poles.
27. 1:22What is a pose? It's pretty much a wave
28. 1:25that has its on time. So, you can see
29. 1:29the flat uh area there is when your beam
30. 1:32is on
31. 1:35and the delay is your off.
32. 1:40Among the pulse types, we have the
33. 1:42continuous wave or the CW.
34. 1:47In comparison to a
35. 1:50ammo shooting from a gun,
36. 1:53we can compare this with a fully
37. 1:56automatic
38. 1:58rifle.
39. 2:00You could see here the bullets, you keep
40. 2:03firing, but over time you run out of
41. 2:05ammo.
42. 2:07In this case,
43. 2:09there is no end point until you release
44. 2:12the foot switch or your trigger. As
45. 2:15such, it's
46. 2:17works well with cutting off your target
47. 2:22or the tissue or the structure of the
48. 2:24body.
49. 2:28The next waveform we will discuss is the
50. 2:32single shot.
51. 2:34The single shot we could simplify it
52. 2:37more like a sniper. One shot per foot
53. 2:40switch press.
54. 2:42very controlled but very slow.
55. 2:47What is optimal is the triple pulse.
56. 2:51So you have three pulses going up in
57. 2:55between our rest or when the laser is
58. 2:58off
59. 3:00just like a semi-automatic rifle.
60. 3:04It's more accurate and safe.
61. 3:12And here is a sample table of the
62. 3:14different pulse modes and their risk
63. 3:18level. Starting from the continuous wave
64. 3:22used for cutting and vaporization of
65. 3:23tissue or body structures, it carries
66. 3:27with the highest thermal risk.
67. 3:29Then we have the single pulse. It's one
68. 3:32isolated pulse each time you press the
69. 3:34foot switch or your trigger. It's very
70. 3:38precise and it's also good for pigment
71. 3:42because you need some type of a longer
72. 3:44absorption time. The risk level is low
73. 3:47to moderate and for multiples
74. 3:51when you stack the li the pulses
75. 3:55quickly
76. 3:57it's best for resurfacing scars and
77. 4:00depth control.
78. 4:03What makes this ideal is the off time in
79. 4:06between the pulse
80. 4:09and you being able to control the delay
81. 4:12time, which is the pause in between the
82. 4:15shot. Bam bam bam instead of bam bam bam
83. 4:20bam bam bam bam.
84. 4:25The importance of pulse timing and
85. 4:27duration is very important especially
86. 4:30when you're treating um your your
87. 4:32patients or your target. You have to
88. 4:34know your TRT which is your thermal
89. 4:38relaxation time
90. 4:40which means it's the time when your
91. 4:43structure cools down enough that it
92. 4:46doesn't get injured.
93. 4:49So the goal is to match the TRT of your
94. 4:53target.
95. 4:55And for your reference, here is a table.
96. 4:58Based on this table,
97. 5:01you should be
98. 5:04setting your device no more than the
99. 5:07thermal relaxation time.
100. 5:10Because if you exceed these parameters
101. 5:13now
102. 5:14you are causing damage electrmal
103. 5:18thermally.
104. 5:21Next is frequency. Frequency is just
105. 5:25bunch of waves
106. 5:27depending on your setting. So the unit
107. 5:30is one hertz which means one pulse or
108. 5:33shot per second. If you have five hertz,
109. 5:37expect when you're pressing on the
110. 5:39button, five sub puloses is delivered
111. 5:42and 10 hertz, 10 pulses per second.
112. 5:49So the way you apply frequency is you
113. 5:52can start slow and get to the same goal
114. 5:57without damaging them on the first
115. 6:02application of energy.
116. 6:05Another important parameter that's
117. 6:07misunderstood is the spot size. Keep in
118. 6:10mind, the larger the spot size, the
119. 6:12deeper the penetration. Refer to the
120. 6:15left figure here on the skin.
121. 6:18You see it's uniformly distributing the
122. 6:22beam hitting lower down the dermis area
123. 6:25while you have a very small spot size
124. 6:29which is intense
125. 6:31and creates a greater thermal damage.
126. 6:34Great for precision
127. 6:37and also cutting.
128. 6:40So when you're treating the way you use
129. 6:42spot size is making sure that you damage
130. 6:46the area that you only target and not
131. 6:50overexpose it when not needed.
132. 6:55Keep in mind the laser triangle. We
133. 6:58consider the laser and what we've
134. 7:00learned today
135. 7:02the target its importance on how it
136. 7:05absorbs the energy.
137. 7:08We need to know how this tissue
138. 7:10interaction the response of the tissue.
139. 7:14Let's practice clinical common sense.
140. 7:17Assess, assess, assess, assess, adjust,
141. 7:20assess, adjust. And lastly,
142. 7:26to lessen thermal injury and to protect
143. 7:28the top layer of the skin is we we need
144. 7:31to have an exercise cooling at all
145. 7:34times. When that technology, especially
146. 7:38with lasers, generate heat, we have to
147. 7:41control the heat by cooling it down.
148. 7:45Finally, we have this golden rule of
149. 7:47lasers. When your clinical endpoints
150. 7:49tell you when to stop, not the brochure.
151. 7:53It's not the settings from a YouTube. If
152. 7:56the end point or your goal is achieved,
153. 7:58stop and adjust. If the end point is not
154. 8:02reached,
155. 8:03safely increase or adjust your settings
156. 8:07by always paying attention also to
157. 8:09what's going on. The pose width, all
158. 8:12these parameters, spot size depend on
159. 8:14the target
160. 8:18and the chromophore physics.
161. 8:21So bear that in mind.
162. 8:24Now we leave this to a qu a question and
163. 8:27answer
164. 8:28section. Thank you very much.