KARLFELDT-Logo-Colored

Photodynamic Therapy (PDT): A Light-Activated Treatment

Photodynamic therapy pairs a light-sensitive medicine with a specific wavelength of light. When the medicine is activated, it produces a local reaction that can damage nearby cells. The right approach depends on the condition, medicine, light source and treatment site.

Here, Dr. Michael Karlfeldt explains how PDT works, what to ask about, and how our team discusses it as part of individualized care.

Red laser light applied through fiber-optic probes during an in-clinic photodynamic therapy session.
Illustrative clinic image. PDT protocols and light-delivery methods vary by diagnosis and treatment site.

How PDT works

PDT has three parts: a photosensitizing medicine, light at a matching wavelength, and oxygen in the treated tissue. The medicine is activated where the light reaches; PDT is generally a local treatment, and light penetration is limited. Different medicines and delivery methods are used for different approved conditions.

  1. Choose the photosensitizer. A clinician selects a medicine and timing based on the diagnosis and treatment plan.
  2. Deliver the medicine. It may be applied to the skin or given by another route, depending on the specific treatment.
  3. Apply the light. A matched light source activates the medicine in the intended area.
  4. Plan aftercare. The team reviews light precautions, side effects and follow-up.
Diagram showing the photosensitizing medicine, light activation and local treatment response in photodynamic therapy
Photodynamic Therapy Process was originally published by the National Cancer Institute. Learn more from the NCI.

A thoughtful, individualized conversation

At The Karlfeldt Center, I look at each person’s diagnosis, goals, current oncology care and overall health before discussing whether PDT or another supportive approach may be appropriate. We coordinate with a patient’s oncology team and explain what is known, what is still uncertain, and what a treatment can and cannot be expected to do.

There is no single protocol that fits every person. Photosensitizers, light delivery, potential benefits and risks vary by condition and treatment. We do not promise that PDT will treat or cure cancer.

Watch Dr. Karlfeldt explain photodynamic therapy

PDT delivery depends on the treatment site

Some PDT procedures use a light source placed close to or within the treatment area. For example, approved medical protocols may use an endoscope or optical fiber to deliver light to selected sites. This is different from simply shining light through the skin, and it is not appropriate for every diagnosis. The specific device, medicine and clinical setting matter.

Ask your clinician: What is the treatment target? Which photosensitizer and light source are used? What evidence applies to my diagnosis? What precautions and follow-up are needed?

1. Select the protocol

The diagnosis and target site guide the choice of photosensitizer, light source and timing.

2. Deliver the medicine

The medicine is given or applied according to the specific clinical protocol.

3. Activate with light

A matched wavelength is directed to the intended treatment area.

4. Review and follow up

Your care team discusses response, side effects, skin or eye precautions and next steps.

Interstitial light delivery

When light needs to reach a site beneath the surface, specialized procedures may use a fiber-optic applicator placed by a trained clinician. Whether an interstitial approach is suitable depends on the diagnosis, anatomy, device and available evidence. Evidence from one tumor type or procedure should not be assumed to apply to another.

See the National Cancer Institute overview of PDT.

Intra-articular (Joint)

Other light-based therapies

Photobiomodulation and other external light-based approaches are not automatically the same as photodynamic therapy. They use different protocols and have different evidence. We discuss the intended use, what is known and the limits of the evidence before considering any option.

Is PDT worth exploring? Start with a conversation

If you are considering PDT, bring your diagnosis, treatment history, current medications and questions. Our team can review whether the approach we offer fits your situation, explain practical details and coordinate with your existing care team.

Schedule a discovery call to discuss your questions with The Karlfeldt Center.

Book an appointment
Call The Karlfeldt Center

Curious how Naturopathic Medicine could help you? Schedule a service or talk to one of our Doctors. See you at The Karlfeldt Center!

Address

3451 E Copper Point Dr. Meridian, ID 83642

208-338-8902

Fax: 208-345-3225

Open Hours​

Monday: 9 AM - 4 PMnnTuesday: 9AM - 5PMnnWednesday: 9AM - 6PMnnThursday: 9AM - 5PMnnFriday: 9AM - 4PM