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laser therapy explained

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Laser therapy treatment or also referred to as Photobiomodulation

The light energy from the lasers is absorbed by cellular components, particularly mitochondria.  This absorption triggers biochemical changes, leading to increased cellular energy production and various cellular responses.

Laser therapy devices commonly utilise specific wavelengths of light, often in the red or near-infrared spectrum. These chosen wavelengths are selected for their capacity to penetrate tissues and stimulate cellular processes without causing harm. It's worth noting that, generally, the longer the wavelength, the deeper the penetration into the tissues. This property makes laser therapy a targeted and effective modality for various applications in healthcare and rehabilitation.

Lasers are classified into different classes based on their potential hazards and safety considerations. The classification system is established by international standards, particularly the International Electrotechnical Commission (IEC) and the American National Standards Institute (ANSI).

The most commonly referenced laser classification system is outlined in the IEC 60825-1 standard and adopted by ANSI.

The classes are designated by Roman numerals, ranging from I to IV, with subcategories denoted by letters.

Class I:

  • Class I lasers are considered safe under normal operating conditions, and exposure to the laser radiation is not known to cause harm. These lasers are low-powered and do not pose a risk for accidental exposure.


Class II:

  • Class II lasers emit visible light, and the natural aversion response (blinking) of the human eye provides adequate protection. They are considered safe when used in a controlled environment. Examples include laser pointers and barcode scanners.


Class IIIa:

  • Class IIIa lasers are low-powered lasers that could potentially cause harm if directly viewed for extended periods. However, the risk of injury is considered low, and accidental exposure is not likely to cause permanent damage. Common examples include some laser light shows.


Class IIIb:

  • Class IIIb lasers are moderate-powered lasers that can pose a significant risk of injury, especially if the beam is viewed directly. Eye protection is crucial when working with Class IIIb lasers. Examples include certain industrial lasers and medical lasers.


Class IV:

  • Class IV lasers are high-powered lasers that can cause serious injury to the eyes and skin if misused. The risk of injury extends to reflections and scattered beams. These lasers are often used in medical, industrial, and research applications.

 

Safety precautions, including protective eyewear and controlled access, are essential.


It's crucial for individuals working with lasers to understand the classification of the lasers they are using and adhere to appropriate safety measures. Laser safety guidelines and precautions should be followed to minimize the risk of accidents and ensure the safe use of laser devices. 

While laser classification primarily denotes safety considerations, higher-powered lasers, such as those in Class IV, do offer advantages in terms of treatment efficiency. The increased power allows for greater tissue penetration and the delivery of higher energy levels. This feature is particularly beneficial for clinics aiming to treat multiple areas during a session. For instance, the use of a Class IV laser significantly reduces treatment times compared to a Class III laser. This efficiency not only benefits clients but also allows practitioners to make optimal use of appointment times by incorporating multiple modalities. The Class IV laser, with its enhanced capabilities, proves to be an ideal choice for achieving both effective treatments and efficient clinic sessions.

The power of a laser, measured in watts (W), plays a crucial role in determining its effectiveness and the depth of penetration during a treatment. 

     1.  Treatment Depth:

  • Higher laser power generally allows for deeper penetration into the targeted tissues. This is particularly important when aiming to treat deeper structures or conditions that require a more significant reach.


     2.  Cellular Response:

  • Laser power influences the amount of energy delivered to the tissues. Adequate energy is necessary to stimulate cellular processes, such as increased ATP production and enhanced metabolism, which contribute to tissue repair and regeneration.


     3.  Treatment Time:

  • Higher laser power can lead to shorter treatment times. With increased power, the therapeutic effects are delivered more efficiently, allowing practitioners to achieve desired outcomes in a shorter duration.


     4.  Tissue Absorption:

  • Different tissues absorb laser light differently. The power level needs to be carefully selected to ensure optimal absorption by the target tissues. Higher power may be required for conditions where deeper penetration is necessary.


     5.  Intensity and Dosage:

  • Laser power, in conjunction with treatment duration, determines the overall dosage or energy delivered to the tissues. This dosage is a critical factor in achieving therapeutic effects without causing adverse reactions.


     6.  Heating Effects:

  • Higher laser power can lead to increased heating effects in tissues. This can be beneficial in certain therapeutic applications, such as promoting blood flow and reducing muscle spasm. However, careful monitoring is essential to prevent overheating and potential tissue damage.

 

     7.  Clinical Applications:

  • The appropriate laser power depends on the specific clinical application. For superficial conditions, lower power may be sufficient, while deeper or more chronic conditions may require higher power for effective treatment.

 

  • It's important to note that the choice of laser power should be made in consideration of the specific goals of the treatment, the targeted tissues, and the characteristics of the condition being addressed. Additionally, safety measures, including appropriate eyewear for both the practitioner and the patient, should be implemented to prevent any potential adverse effects associated with laser exposure. 

Treatment Process:

  • The therapy is typically administered by directing the laser or LED light onto the skin over the target area.Treatment sessions are relatively short, usually lasting a few minutes to around 30 minutes, depending on the condition and the specific device used.

  • The number of sessions required varies, and the treatment plan is often determined based on the individual's response and the nature of the condition being treated.

The calculation of joules per square centimeter (J/cm²) for a laser dose involves considering the energy delivered by the laser and the area over which that energy is distributed. The formula for calculating laser dose in joules per square centimeter is:

            Energy (J) = Power (W) × Time (s)

            Dose (J/cm²) = Energy (J)

                                       Area (cm²)

Here's a step-by-step guide:

 

1.  Determine the Energy (J):  Multiply the laser power (in watts) by the treatment time (in seconds) to find the total energy delivered.

            Energy (J) = Power (W) × Time (s)

2.  Determine the Area (cm²):  If the laser is applied over a specific area, measure or calculate the area in square centimeters.

            Area (cm²) = Length (cm) x Width (cm)

3.  Calculate Dose (J/cm²):  Divide the energy (in joules) by the area (in square centimeters) to obtain the dose.

            Dose (J/cm²) = Energy (J)

                                      Area (cm²)

It is very important to use consistent units for power (watts), time (seconds), energy (joules), and area (square centimeters) in your calculations.

For example, if you have a laser with a power of 5 watts applied for 10 seconds over an area of 20 cm²:

            Energy (J) = 5 W × 10 s = 50 J

            Dose (J/cm²) = 50 J   = 2.5 J/cm²

                                      20 cm²

This calculated dose represents the amount of energy delivered per square centimeter during the laser treatment. Adjusting the power, time, or treatment area will impact the calculated dose, and these parameters should be carefully selected based on the therapeutic goals and the specific characteristics of the condition being treated.

Applications:

  • Pain Management:  Laser therapy is commonly used for the relief of musculoskeletal pain, including conditions such as arthritis, back pain, and joint disorders.

  • Tissue Repair and Regeneration: It may aid in the healing of wounds, injuries, and surgical incisions by promoting cell growth and tissue repair.

  • Inflammation Reduction: Laser therapy can help reduce inflammation, making it useful in conditions like tendinitis and bursitis.

  • Neuropathy: Some forms of laser therapy are used to manage peripheral neuropathy, a condition characterized by nerve damage.

Safety:

Laser therapy is generally considered safe when administered by trained professionals. It is non-invasive and does not involve the use of medications.

The low-level nature of the lasers used means that there is minimal risk of tissue damage or burns.

Further reading:

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