electromagnetic.3

What are the non-ionizing EM modalities discussed in this lecture?

Shortwave diathermy, microwave, infrared, visible light, and ultraviolet light.

What are the ionizing forms of electromagnetic radiation?

X-rays and gamma rays.

What is the primary clinical use of infrared radiation?

Superficial heating.

What are the main clinical uses of UV radiation?

Treatment of skin disorders and wound healing.

What are the main clinical uses of shortwave diathermy?

Deep tissue heating, pain management, edema reduction, and wound healing.

What does LASER stand for?

Light Amplification by Stimulated Emission of Radiation.

What are the 3 defining characteristics of LASER light?

Monochromatic, coherent, and directional.

What does monochromatic mean?

The light has a single wavelength.

What does coherent mean?

The light waves are in phase.

What does directional mean?

The light travels in a parallel, concentrated beam.

What are other terms for low-level LASER therapy?

LLLT and cold laser.

What are the 3 types of UV radiation?

UVA, UVB, and UVC.

What is the wavelength of UVA?

320–400 nm.

What is the wavelength of UVB?

290–320 nm.

What is the wavelength of UVC?

Less than 290 nm.

What are the general physiological effects of UV radiation?

Skin erythema, tanning, epidermal hyperplasia, and vitamin D synthesis.

Which UV type is specifically used for wound healing?

UVC.

What skin disorders may be treated with UV?

Psoriasis, acne, alopecia, scleroderma, eczema, and atopic dermatitis.

How can UVC assist wound healing?

Promotes granulation tissue, increases local blood flow, increases vitamin D production, and helps remove necrotic tissue.

What is MED?

Minimal erythemal dose.

Why is MED determined before UV treatment?

To identify the minimum UV dose that produces a mild erythemal response and guide treatment dosage.

What protective equipment is required during UV treatment?

UV-protective goggles for both patient and clinician.

How should a UV lamp be positioned?

Perpendicular to the treatment area and at the same distance used during MED testing.

How is UV treatment progressed?

Increase exposure time by about 25–50% each treatment, with a maximum of 5 minutes.

What should be assessed after UV treatment?

Skin response and patient response to the dose.

What are major UV contraindications?

Eye irradiation, skin cancer, pulmonary TB, cardiac/kidney/liver disease, lupus, and fever.

What are major UV precautions?

Photosensitizing medications/supplements, photosensitivity, recent X-ray exposure, and erythema from a previous UV dose.

A patient taking a photosensitizing medication is referred for UV treatment. What should you do?

Treat it as a precaution because the patient may have an exaggerated response to UV exposure.

A patient still has erythema from the previous UV session. Should you immediately increase the dose?

No. Existing erythema is a precaution and indicates the skin has not fully recovered.

Why must the same lamp distance be used during treatment as during MED testing?

Changing the distance changes the intensity delivered, making the MED-based dose inaccurate.

A patient with psoriasis is being treated using UV. What is the key parameter used to guide initial dosing?

Minimal erythemal dose.

What is diathermy?

Application of shortwave or microwave electromagnetic energy for therapeutic purposes.

What are the wavelength ranges used with diathermy?

Shortwave: 3–200 m; microwave: 1 mm–1 m.

What are the main advantages of diathermy over modalities such as ultrasound or moist heat?

It heats deeper tissues and can treat larger surface areas.

What are the 2 general forms of diathermy effects?

Thermal and nonthermal.

Which form of diathermy produces thermal effects?

Continuous diathermy.

Which form of diathermy produces primarily nonthermal effects?

Pulsed shortwave diathermy.

What are the thermal effects of diathermy?

Increased tissue temperature, vasodilation, increased nerve conduction, increased pain threshold, and increased soft tissue extensibility.

What are the primary indications for thermal diathermy?

Decreasing pain/spasm and improving ROM.

What are the nonthermal effects of pulsed shortwave diathermy?

Increased microvascular perfusion and altered cell membrane permeability/cellular activity.

What are indications for nonthermal diathermy?

Pain and edema control, soft tissue healing, peripheral nerve regeneration, osteogenesis, and OA.

A patient has restricted ROM and muscle spasm. Which type of diathermy is more appropriate?

Continuous thermal diathermy because the goal is increased tissue temperature and extensibility.

A patient has acute edema but you do not want to significantly heat the tissue. Which type of diathermy is more appropriate?

Pulsed shortwave diathermy for nonthermal effects.

What sensation should a patient report during thermal diathermy?

Mild warmth.

What sensation should a patient report during nonthermal diathermy?

No warmth, possibly slight tingling.

What is the difference between inductive and capacitive diathermy applicators?

Inductive coils/drums are placed directly over or close to the skin; capacitive plates are positioned about 2–10 cm from the skin.

What are contraindications to all forms of diathermy?

Implanted biomedical devices and pregnancy.

What are thermal diathermy contraindications?

Metal implants, malignancy, eyes, testes, and growing epiphyses.

What are precautions for diathermy?

Nearby electronic/magnetic equipment and obesity.

Why is metal removal important before diathermy?

Metal can interact with electromagnetic energy and increase the risk of undesirable heating or interference.

Why can obesity affect diathermy treatment?

It may alter energy penetration and tissue heating, so treatment response must be monitored carefully.

A patient with a pacemaker is referred for diathermy. What is the correct response?

Diathermy is contraindicated because of the implanted biomedical device.

A child has an open growth plate near the treatment area. Can thermal diathermy be applied directly over it?

No. Growing epiphyses are a contraindication for thermal diathermy.

A patient has a metal implant near the knee and needs deep heating. Is thermal diathermy appropriate?

No. Metal implants are contraindicated for thermal diathermy.

Which modality is better suited for heating a large, deep tissue area: moist heat or diathermy?

Diathermy.

What is photobiomodulation?

Cellular effects produced when therapeutic light is absorbed by chromophores.

What happens when LASER light is absorbed by chromophores?

It can increase mitochondrial ATP production, increase RNA/collagen synthesis, alter prostaglandins, alter serotonin/endorphins, and reduce nociceptor activity.

What is photostimulation?

Cellular stimulation from lower LASER doses that promotes functions such as ATP and collagen production.

What is photoinhibition?

Suppression of cellular or neural activity at higher doses, used for effects such as pain reduction and bacterial inhibition.

What does the Arndt-Schultz principle describe in LASER therapy?

LASER effects are dose dependent.

According to the Arndt-Schultz principle, what do lower LASER doses generally produce?

Photostimulation.

According to the Arndt-Schultz principle, what do higher LASER doses generally produce?

Photoinhibition.

Which LASER response is more associated with wound healing?

Photostimulation.

Which LASER response is more associated with pain management?

Photoinhibition.

Why can too high of a LASER dose reduce the desired healing response?

Higher doses may shift the response from stimulation toward inhibition or tissue suppression.

A patient is being treated primarily to enhance healing. Would you expect a relatively lower or higher LASER dose?

Relatively lower, to favor photostimulation.

A patient is being treated primarily for pain inhibition. Would you expect a relatively lower or higher LASER dose?

Relatively higher, to favor photoinhibition.

What effect does LASER have on ATP production?

It can improve mitochondrial function and increase ATP production.

Why is increased ATP helpful for tissue healing?

ATP provides energy for cellular processes involved in repair.

How can LASER affect collagen?

It can increase procollagen, collagen synthesis, and mRNA involved in collagen production.

How can LASER modulate inflammation?

By increasing blood flow and affecting immune and repair cells such as lymphocytes, mast cells, macrophages, fibroblasts, keratinocytes, and endothelial cells.

Which wavelengths were noted as particularly effective for bacterial inhibition?

Approximately 405–670 nm.

How can LASER affect nerve tissue?

It can alter nerve conduction velocity, action potential activity, nerve regeneration, scarring, and nociceptor activity.

What are common indications for LASER therapy?

Soft tissue/bone healing, OA, RA, lymphedema, carpal tunnel syndrome, diabetic peripheral neuropathy, and pain management.

What are major LASER contraindications?

Direct eye irradiation, recent radiation treatment, hemorrhage-prone areas, thyroid/endocrine glands, and malignancy.

How long after radiation treatment is LASER listed as contraindicated?

Within 4–6 months.

What are LASER precautions?

Low back/abdomen during pregnancy, epiphyseal plates in children, and areas of reduced sensation or circulation.

What are possible adverse effects of LASER?

Tingling, mild erythema, rash, burning, increased pain, numbness, burns, and retinal damage from eye exposure.

Why are areas of reduced sensation a LASER precaution?

The patient may not accurately detect excessive heating, discomfort, or tissue irritation.

Why are protective goggles required with LASER?

Brief direct exposure can cause retinal damage.

What is the therapeutic wavelength range for LASER?

Approximately 600–1300 nm.

What happens to LASER wavelengths below 600 nm?

They are attenuated by tissue.

What happens with wavelengths above 1300 nm?

Interactions are primarily thermal.

What is LASER power measured in?

Watts or milliwatts.

What is power density?

Average power delivered per unit area.

What is the formula for power density?

Power density = power ÷ beam area, expressed in W/cm².

What class are therapeutic LASERs typically?

Class 3B.

What is the power range of Class 3B LASERs?

Greater than 5 mW but less than 500 mW.

Why is Class 3B LASER considered hazardous to the eyes?

Brief exposure can cause permanent eye injury.

What is energy density?

Total electromagnetic energy delivered per unit area over the treatment.

What unit is used for LASER energy density?

J/cm².

How does energy density differ from power?

Power is the rate of energy delivery, while energy density is the total amount of energy delivered per unit area.

A device has a high power but is applied for a very short time. Does high power automatically mean high energy density?

No. Energy density also depends on total treatment time and area.

What energy density is suggested for soft tissue healing?

5–16 J/cm².

What energy density is suggested for fracture healing?

5–16 J/cm².

What energy density is suggested for acute arthritis?

2–4 J/cm².

What energy density is suggested for chronic arthritis?

4–8 J/cm².

What energy density is suggested for lymphedema?

1.5 J/cm².

What energy density is suggested for neuropathy?

10–12 J/cm².

What energy density is suggested for acute soft tissue inflammation?

2–8 J/cm².