Razvoj numeričnega modela laserske epilacije

Klaneček, Žan (author), Milanič, Matija (mentor), Simončič, Urban (co-mentor)

Razvit je bil protokol za simuliranje odstranjevanja dlak, ki temelji na mrežnem modelu iz tetraedrov. Ustreznost protokola je pri podobnih simulacijskih pogojih bila potrjena z rezultati drugih študij. Površinski dvig temperature zaradi obsevanja je bil izmerjen tudi eksperimentalno, rezultati pa primerjani in potrjeni preko simulacij. Na različnih realnih mrežnih modelih kože z dlakami so za aktualne parametre odstranjevanja dlak z laserjem Nd:YAG bili analizirani rezultati kliničnih raziskav. Preko ocene toplotne poškodbe smo pokazali, da lahko izide kliničnega odstranjevanja dlak, do neke mere, z numeričnim modelom tudi napovemo. Večja energija pulza predstavlja večjo verjetnost za nepopravljivo poškodbo kritičnih predelov dlake. Vsiljeno hlajenje s kriogenskim razpršilom zmanjša verjetnost poškodbe vrhnje plasti kože. Hkrati je bil raziskan vpliv kota izraščanja dlak iz kože ter vpliv sosednosti večih dlak. Izkaže se, da v primeru, ko dlaka izrašča navpično iz kože, pride do manjše toplotne poškodbe lasne čebulice kot v primerih, ko dlaka izrašča pod večjim kotom. Podobno se izkaže v zmanjšanju toplotne poškodbe centralne dlake v primeru, ko obsevamo več dlak hkrati. Če obsevamo šop večih dlak, bo poškodba dlak na periferiji snopa manjša. Na končno poškodbo dlake najbolj vpliva čas obsevanja in kratek čas relaksacije po pulzu. Vso nadaljnje ohlajanje h končnemu rezultatu doprinese relativno malo.

• Language: Slovenian
• Keywords: epilacija dlak, numerična simulacija, Monte Carlo, toplotni transport, mrežni model, toplotna poškodba
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: FMF - Faculty of Mathematics and Physics
• Year: 2019
• PID: 20.500.12556/RUL-110385
• COBISS.SI-ID: 3369572
• Publication date in RUL: 14.09.2019

Secondary language

• Language: English
• Title: Development of a numerical model of laser epilation

Abstract

A protocol for simulating hair removal was developed based on tetrahedral mesh. The relevance of the protocol was compared with results of other studies using similar simulation conditions. Surface temperature increase due to irradiation was also measured, experimentally. Results were then compared and confirmed with simulations. Different mesh models of skin with hair were used to analyse results of clinical studies on hair removal using Nd:YAG laser. With the assessment of thermal injury with our numerical model we proved that a clinical outcome can be predicted to some extent. Higher energy of the pulse presents greater risk of irreversible damage of critical parts of hair. Forced cooling with cryogenic spray lowers the risk of damaging upper layer of skin. At the same time, the impact of hair growth angle and the impact of adjacent hair were researched. It turns out that in cases where hair grows from skin vertically the damage on hair bulb is lower than in cases where hair grows at a greater angle. When a bunch of hair is irradiated in one pulse the thermal injury on central hair is reduced. If a bunch of hair is irradiated, the damage on hair on the periphery of the field will be lower. The final thermal injury is mostly dependent on time of irradiation and short relaxation time after pulse. Any further cooling does not contribute that much to the final result.

• Keywords: hair epilation, numerical simulation, Monte Carlo, heat transport, mesh, thermal injury