3. Enhance

Enhance

As an example the student will be able to choose the right atomic levels to use in order to calibrate a laser which can destroy tumoral skin cells. 
The student will choose the right frequencies knowing that the cells to be destroyed are sensitive to specific frequencies. 

The main types of lasers currently used in cancer treatment include:

• Carbon dioxide (CO₂)
• Argon (Ar)
• Neodymium: yttrium aluminum garnet (Nd: YAG) 

Doctors and other health experts who use these lasers need special training in how to use and safely handle them.

Carbon dioxide (CO2) lasers

CO₂ lasers don’t go deep into tissues like Nd: YAG lasers. They can cut or vaporize (dissolve) tissue and cause little bleeding. They do little damage to the surrounding or deep tissue. They are used to treat pre-cancers and some early-stage cancers.

Argon lasers

Argon lasers, like CO₂ lasers, only go a short distance into tissue. They are useful in treating skin problems and some types of eye tumors. Sometimes, they are used during colonoscopies (tests to look for colon cancer) to remove polyps before they become cancer. They also can be used with light-sensitive drugs to kill cancer cells in a treatment known as photodynamic therapy (PDT).

Another way they can be used is to help stop bleeding by sealing blood vessels in patients who are getting radiation therapy for certain types of cancer. This might be needed because sometimes radiation therapy can damage the blood vessels near tumors, causing them to tear and bleed.

Nd: YAG (Neodymium: Yttrium-Aluminum-Garnet) lasers

Light from this laser can go deeper into tissue than other types of lasers, and it can make blood clot quickly. Nd: YAG lasers can be used through thin flexible tubes called endoscopes to get to hard-to-reach parts inside the body, such as the esophagus (swallowing tube) or the large intestine (colon). This light can also travel through flexible optical fibers (thin, clear tubes) put into a tumor, where the light's heat can destroy it.

Treating cancer with lasers

Lasers can be used in 2 main ways to treat cancer:

• To shrink or destroy a tumor with heat 
• To activate a chemical (a photosensitizing agent) that kills only the cancer cells 

Lasers can be used alone or with other cancer treatments, such as chemotherapy (chemo) or radiation therapy.

Shrinking or destroying tumors directly

The CO₂ and Nd: YAG lasers are used to shrink or destroy tumors. They can be used with thin, flexible tubes called endoscopes. Endoscopes let doctors see and work inside certain parts of the body that could not otherwise be reached except by major surgery. Using an endoscope also helps position the laser beam to hit its target accurately.

Here are some examples of how lasers treat cancer or pre-cancerous conditions:

• Colorectal polyps: Lasers can be used to remove small growths in the colon and rectum that might become cancer called polyps. 
• Pre-cancers and early cancers: Lasers can be used to treat some pre-cancers of the skin and cervix, and early cancers of the skin. 
• Advanced cancer: Lasers might be used to treat cancers causing a blockage in the airway by destroying a part of the tumor. 
• Brain tumors: Laser-induced interstitial thermotherapy (LITT) can be used to treat some brain tumors. It uses heat to help shrink tumors by damaging cells or taking away the things they need to live (like oxygen and food). 

Lasers using photodynamic therapy

For most types of photodynamic therapy (PDT), a special drug called a photosensitizing agent is put into the bloodstream. Over time, it is absorbed by body tissues. The drug stays longer in cancer cells than in normal cells.

Photosensitizing agents are turned on or activated by certain types of light. When cancer cells that contain the photosensitizing agent are exposed to light from an argon laser, it causes a chemical reaction that kills them. Light exposure must be carefully timed so that it’s used when most of the agent has left healthy cells but is still in the cancer cells.
PDT is sometimes used to treat cancers and pre-cancers of the esophagus, bile duct, bladder, and certain kinds of lung cancer that can be reached with endoscopes.

It is also being studied for use in other cancers, such as brain, pancreas, and prostate. Researchers are looking at different kinds of lasers and new photosensitizer drugs that might work better.