Radiation-induced necrosis is a serious reaction to radiation treatment. It may result from the death of tumor cells and associated reaction in surrounding normal brain or it may result from the necrosis of normal brain tissue surrounding the previously treated metastatic brain tumor. Such reactions tend to occur more frequently in larger lesions, either primary brain tumors or metastatic tumors.
The diagnosis of radiation-induced necrosis is difficult to confirm. Many patients have a mixture of tumor and radiation necrosis and a biopsy may be necessary to distinguish it. Neither symptoms nor radiographic findings clearly distinguish radiation-induced necrosis from tumor. However, the FDG-PET Scan (which measures cellular metabolism) and T1-SPECT studies are useful in differentiating radiation-induced necrosis from recurrent tumor.
Hyperbaric Oxygen Therapy (HBOT) is a useful therapeutic option for patients with confirmed symptomatic radiation necrosis. Until the new millenium, the only treatment for patients was pentoxifyline or heparin therapy, and it was almost always unsuccessful. Both Duke University for Hyperbaric Oxygen Therapy and the University of Cincinnati previously had clinical trials on this science.
The most common condition treated at some Hyperbaric Oxygen Therapy Centers is tissue injury caused by brain radiation therapy for cancer. Wound healing requires oxygen delivery to the injured tissues. Radiation damaged tissue has lost blood supply and is oxygen deprived. Chronic radiation complications result from scarring and narrowing of the blood vessels within the area which has received the treatment. Hyperbaric Oxygen Therapy provides a better healing environment and leads to the growth of new blood vessels in a process called re-vascularization. It also fights infection by direct bacteriocidal effects. Using hyperbaric treatment protocols, "most" patients with chronic radiation injuries can be cured.
Hyperbaric oxygen therapy is administered by delivering 100 percent oxygen at pressures greater than atmospheric (sea level) pressure to a patient in an enclosed chamber. Hyperbaric oxygen acts as a drug, eliciting varying levels of response at different treatment depths, durations and dosages, and has been proven effective as adjunctive therapy for specifically indicated conditions.
Oxygen is a natural gas that is absolutely necessary for life and healing. Purified oxygen is defined as a drug but is the most natural of all drugs. Oxygen under pressure is still the same gas but is more able to penetrate into parts of the body where the arterial flow is hindered, producing ischemia (loss of blood flow) and hypoxia (lack of oxygen). When oxygen under pressure is breathed by a patient in a sealed chamber, it is termed a hyperbaric oxygen treatment (HBOT).
In addition to raising the arterial levels of oxygen 10 to 15 times higher than that produced by normal atmospheric pressure, the pressure exerted within the body can and does exert therapeutic benefits on acute and chronically traumatized and swollen tissus.
If on medicare, the approved course is 2.0 atm (two times above atmospheric pressure) for 90 minutes 20-30 sessions. For hyperbaric oxygen therapy to be covered under the Medicare program in the United States, the physician must be in constant attendance during the entire treatment. This is a professional activity that cannot be delegated in that it requires independent medical judgment by the physician. The physician must be present, carefully monitoring the patient during the hyperbaric oxygen therapy session and be immediately available should a complication occur. This requirement applies in all settings and no payment will be made by Medicare unless the physician is in constant attendance during the procedure.
Who Should Avoid This Therapy?
Avoid these treatments if you have a seizure disorder, emphysema, a high fever, or an upper respiratory infection. Do not undergo them if you have a severe fluid build-up in the sinuses, ears, or other body cavities. Forego them if you've had surgery for optic neuritis, or have ever had a collapsed lung. Avoid them, too, if you are taking doxorubicin (Adriamycin), cisplatin (Platinol), disulfiram (Antabuse), or mafenide acetate (Sulfamylon).
Pregnancy was once considered a contraindication for hyperbaric therapy. However, it's now deemed acceptable if a condition will cause long-term damage to the mother or fetus. For example, the treatments are given to pregnant women with carbon monoxide poisoning, which is toxic to both mother and child.
What Side Effects May Occur?
Seizures, a result of the direct effect of oxygen on the brain, are the most serious side effect associated with hyperbaric therapy. The risk is estimated at one in 5,000. Every chamber is equipped with a quick-release mechanism. If a seizure occurs, the oxygen will be immediately released and the seizure will subside.
Minor side effects include popping of the ears similar to that experienced in a descending aircraft. Sinus pain, earache, and headache are other possible side effects. In fact, pain may occur in any body cavity where air can get in but can't get out. For example, dental pain may occur if a filling has trapped air beneath it. In rare cases, pressurized oxygen may rupture an eardrum.
Sources:
http://www.hbot4u.com/radiation.html
http://www.hbot.com/frontpage.htm
http://health.ucsd.edu/specialties/hyperbaric
http://www.baromedical.com/about_hyp...c_medicine.asp
http://www.spinalrehab.com.au/Updates/Hyperbaric%20Oxygen%20treatments%20ca n%20help%20patients%20with%20radiation-induced%20brain%20injuries.htm