Lec 23 Radiación Ultravioleta (umh1723 2014-15)

Applications of Ultraviolet Radiation in Physiotherapy

Historical Context and Current Relevance

• The topic is relatively straightforward, with limited applications in physiotherapy known today. Historically, there were significant benefits from ultraviolet radiation in rehabilitation.

• Currently, therapeutic uses are primarily found in dermatology and some preventive measures against infections, which fall outside the typical scope of physiotherapy.

Emerging Fields and Competitions

• There is a growing interest among physiotherapists in aesthetic and beauty fields where ultraviolet applications are more frequently utilized.

• Despite this trend, many practitioners lack the necessary qualifications to safely use such equipment, leading to potential risks if not applied correctly.

Understanding Electromagnetic Radiation

Types of Ultraviolet Radiation

• Three types of ultraviolet radiation exist based on wavelength: A, B, and C. Each has distinct physical characteristics related to frequency and energy levels.

• Only one type of ultraviolet radiation has therapeutic or preventive applications; others are mainly used for cosmetic purposes.

Health Implications

• Historically, ultraviolet radiation was used to prevent diseases by aiding vitamin D synthesis. Insufficient exposure can lead to nutritional deficiencies.

• Certain professional groups may lack adequate sunlight exposure due to geographical location or work conditions (e.g., underground jobs), necessitating artificial UV exposure for health maintenance.

Physiological Effects and Application Methodologies

Importance of Sunlight Exposure

• While natural sunlight provides a broad spectrum of benefits including visible light and infrared radiation, specific physiological effects can be achieved solely through targeted ultraviolet exposure.

Dosage Considerations

• Discusses how historical methodologies determined appropriate dosages for patients based on skin type and absorption capabilities. Variability exists among individuals regarding their response to UV radiation.

Safety Measures

Understanding Ultraviolet Radiation and Its Applications

Overview of Ultraviolet Bands

• The ultraviolet spectrum consists of three bands, with only one having therapeutic applications in medicine.

• The band with wavelengths from 390-320 nm has the lowest energy and maximum penetration but minimal biological effects.

• There is confusion regarding why longer wavelengths (lower energy) have maximum penetration; this contradicts common expectations about energy levels.

Biological Effects and Indications

• Immediate pigmentation occurs with minimal erythema in the first band, indicating its primary use in aesthetic applications.

• The second band produces marked erythema and delayed pigmentation, suggesting different therapeutic indications compared to the first band.

High Energy Band Characteristics

• The third band has the highest energy due to its shorter wavelength, which should theoretically allow for maximum penetration; however, it produces less erythema and pigmentation than expected.

• Erythema can be induced by various forms of radiation (galvanic or infrared), leading to beneficial inflammatory responses that enhance microcirculation and tissue nutrition.

Therapeutic Applications

• Immediate pigmentation with minimal erythema suggests a focus on aesthetic outcomes rather than medical treatment.

• Different bands serve distinct purposes: some are better suited for quick tanning while others may lead to more pronounced skin reactions.

Clarifications on Radiation Effects

• It is clarified that UV radiation alone can induce pigmentation without needing infrared radiation; thus, high doses are not necessary for tanning.

• Understanding the main indications for each UV band helps clarify their respective uses in therapy versus aesthetics.

Conclusion on Penetration Levels

Understanding Ultraviolet Radiation and Its Effects

The Nature of Ultraviolet Radiation

• Discussion on the penetration of ultraviolet radiation into the skin, highlighting a lack of justification for why UV has greater penetration compared to absorption by the skin.

• Mention that UV-C does not have patriotic effects and is absorbed in skin layers, raising questions about its effectiveness based on wavelength and frequency patterns.

• Inquiry into color perception related to skin types and how it affects understanding of UV interaction with different skin components.

Methodology of Application

• Explanation of artificial lamp application methodology, focusing on two variables: distance from the source and application time as key factors in dosage.

• Clarification that intensity modification is not allowed; manufacturers provide fixed power output which cannot be adjusted during use.

Practical Considerations in Application

• Emphasis on maintaining perpendicularity during application for optimal results, referencing previous discussions about visible and invisible radiation.

• Description of gas excitation through electromagnetic radiation, detailing how atomic stability can lead to emission when returning to original states.

Safety Measures During Treatment

• Discussion on safety measures regarding lamp positioning; concerns about potential breakage are noted but deemed unlikely.

• Importance of protecting sensitive areas (e.g., eyes, genital regions), emphasizing direct reaction risks associated with UV exposure.

Individual Variability in Response to Radiation

• Notation that individual responses vary significantly due to personal characteristics such as skin type and pigmentation; this variability must be accounted for in treatment dosages.

• Introduction of minimum dose concepts for effective treatment while considering individual differences; highlights need for tailored approaches based on patient characteristics.

Dosage Calculation Over Time

• Explanation that after determining initial doses, adjustments can be made based on session progression while monitoring individual reactions over time.

What is the Necessary Exposure Time for Minimum Erythema?

Understanding Exposure Time in Therapeutic Applications

• The speaker discusses the importance of determining the necessary exposure time to provoke a minimum erythema, which will be used as a therapeutic dosage reference.

Protocols and Techniques for Irradiation

• A description of an old protocol using a cardboard device with multiple holes, known as "sencíómetro de cobax," which allows for varying irradiation times across different areas.

• The method involves covering certain holes while exposing others to specific irradiation durations, accumulating exposure over time.

Observing Erythema Response

• After applying different exposure times, the speaker measures erythema response with a latency period of 8 to 12 hours to identify the minimum effective dose.

• Emphasizes maintaining consistent distance during application (between 50 and 100 centimeters), ensuring accurate dosage calculations based on initial treatment exposure.

Effects of Continuous Radiation Exposure

• Discusses potential consequences of repeated radiation exposure on skin health, including cellular death and hyperkeratosis as defensive reactions leading to premature aging and increased cancer risk.

• Highlights historical texts that recommend limiting exposure before starting new experimental cycles due to risks associated with prolonged radiation effects.

How Does Skin Type Affect Erythema Response?

Individual Variability in Erythema Threshold

• The speaker notes that individuals may require longer exposure times (e.g., 120 seconds) based on their skin type (e.g., pale or brown skin tones).

• Establishes that achieving minimal erythema safely requires careful consideration of individual characteristics and previous exposures.

Physiological Responses to Radiation

• Defines erythema as vasodilation resulting from inflammatory processes, contrasting it with infrared responses due to differing latency periods.

• Factors such as race, skin color, age, sex, body region, and prior habituation significantly influence tolerance levels towards radiation exposure.

What Are the Physiological Effects of UV Exposure?

Short-Term Reactions Post-Irradiation

• Describes mild erythematous reactions without pain or irritation lasting approximately 24 hours after initial UV exposure.

• Mentions how these reactions can vary among individuals based on their baseline skin conditions following sun exposure.

Long-Term Consequences of Overexposure

• Discusses severe burns resulting from excessive UV radiation leading to blistering and other adverse effects.

The Role of Vitamin D Synthesis in Skin Health

Chemical Reactions Induced by UV Light

Understanding Exposure Time and Dosage in Ultraviolet Therapy

Fixed Intensity and Distance

• The intensity of the treatment is fixed, as well as the distance maintained during exposure. The only variable affecting the outcome is the exposure time.

Gradual Increase in Exposure Time

• For a person with a minimum effective dose (med) of 15 seconds, it is recommended to gradually increase exposure time each day, starting from 15 seconds to one minute on subsequent days. A sudden jump in dosage may not yield expected results.

Minimum Effective Dose

• The minimum dose that does not provoke any noticeable effects is discussed. It suggests that 15 seconds may not be sufficient to elicit a response in individuals from certain demographics, indicating variability based on geographical factors.

Therapeutic Effects of UVB Radiation

• Approximately 300 nm wavelength falls within the optimal range for therapeutic effects of UVB radiation, which is essential for achieving erythema beneficial for treatment purposes.

Dosing Strategy and Erythema Levels

• Different dosing levels are outlined: sub-eritematosa, mitis, normalis, fortis, and eritematosa. These levels help quantify doses throughout therapy sessions while monitoring visible skin reactions like redness or irritation.

Effects of Overexposure and Skin Reactions

Palpable Redness and Irritation

• Discusses how palpable redness and irritation can occur after overexposure to UV light. Symptoms typically resolve within two to three days but indicate how much dosage was absorbed during initial exposures.

Physiological Aspects of Erythema

• Highlights different types of skin responses based on color changes due to UV exposure. It emphasizes that visible signs can indicate excessive exposure leading to long-lasting pigmentation changes.

Vitamin D Synthesis through UV Exposure

Role of Provitamin D Conversion

• Explains that provitamin D converts into vitamin D only when exposed to specific wavelengths of ultraviolet light. Without adequate UV exposure, this transformation cannot occur effectively.

Controlled Environments for Treatment

General Guidelines for Treatment Application

• Discusses general practices regarding localized versus generalized applications in controlled environments such as specialized rooms designed for UV treatments.

Technical Considerations in Ultraviolet Therapy

Photothermal Effects

• Addresses technical challenges related to emitting pure ultraviolet radiation due to overlapping visible light emissions from lamps used in therapy settings.

Indications for Dermatological Applications

Current Uses in Dermatology

• Lists various dermatological conditions treated with ultraviolet therapy including acne, dermatosis, fungal infections, psoriasis among others; highlighting extensive research supporting these applications.

Professional Practices and Health Implications

Impact of Environmental Factors on Health

• Discussion on how certain professional groups in various countries may experience deficiencies due to environmental factors, particularly during communal meals.

Body's Response to External Stimuli

• The body exhibits a memory effect that allows it to return to its normal state after ceasing exposure to harmful stimuli, highlighting the resilience of human physiology.

Dermatological Treatments and Their Benefits

• Emphasis on dermatology as a field with significant therapeutic applications, including wound healing and preventive care through vasodilation effects.

Seasonal Health Challenges

• Winter exacerbates health issues; recommendations include using magnetotherapy for tissue regeneration and immune system activation, especially in patients with weakened defenses.

Caution in Beauty Treatments