Three-Dimensional Radiation Treatment

Three-Dimensional Conformal Radiation Treatment (3D-CRT) is another type of internal radiation therapy. The need to prefer an internal radiation therapy over traditional external beam radiotherapy is necessary as the new methods of internal radiation makes it easier to target more precisely the tumor without damaging the other areas or healthy organs. Whereas in external beam radiotherapy, the oncologists has to go through numerous Computed Tomography scans (CT), nuclear imaging scans (NMRI) and Magnetic resonance imaging (MRI) and the worst thing about this type is that it can cause damage to the healthy organs as it is not precise enough as compared to any internal radiation therapy. One of these internal radiation therapies is 3D-CRT (Three-Dimensional Conformal Radiation Treatment).

Firstly, MRI, PET Scans and CT Scans of a patient is gathered, which are actually two-dimensional images, then they are put in concave-shaped or dome-shaped rotating projector. This projector is plugged into a computer, which creates projections of the images as three-dimensional holograms. Now the interesting thing about this that it doesn’t create pictorial images like we used to see in any other tests, but these light images  show characteristics like shape, location and size of the cancer tumor and also the organs which are affected.

Now to create a customized radiation beam oncologists use these tools:

Multi-leaf collimator

It is fixed to the head of the radiation machine. This either blocks or allows the radiation from penetrating the target. It will create the initial size and shape of the doorway through which radiation beams will be emitted.

Custom-fabricated

It is made by lead, which is used to prevent the flow of light. They are set around the doorway to further conform radiation beams according to the shape of the tumor.

Are there any risks?

This question must arise in your mind, and the answer is yes there are some side-effects associated with 3D-CRT.

Esophagitis

Inflammation in esophagus (it is a tube for food that runs from throat to stomach). Around two weeks after beginning of the treatment you will observe this symptom, but generally it disappears more or less 2-3 weeks after the treatment is ended.

Mucositis

Inflammation of oral mucosa (membrane of gums, throat and mouth). You will observe symptoms like thick saliva, dry mouth, sores and difficulty in swallowing and chewing. This symptom will disappear within few weeks after the end of the treatment.

Pneumonitis (Radiation)

Inflammation of the lungs. You will observe this symptom around two weeks at the beginning of the treatment. It is accompanied by the symptoms like breathlessness due to exertion, fever and dry cough. These symptoms are not permanent, but it will scar the lungs permanently.

Brachytherapy

What is Brachytherapy?

Brachytherapy is a kind of radiation therapy. The harmful radiation is administered through a small object put inside the tumor; due to this it minimizes the damage of healthy tissue. Thus, this tumor has more narrow focus on the growth of tumor.

I want to tell you one very significant thing about Brachytherapy that it does not use any external radiation like other traditional radiation therapies. Due to this Brachytherapy may also be called internal radiation therapy and the other traditional radiation therapies are referred to as EBRT (External Beam Radiation Therapy).

In treating Mesothelioma or Lung cancer, brachytherapy is not used as a standard treatment! Although still the researchers are testing this way of treatment in clinical trials and from early studies it shows very promising and positive results to increase the life expectancy and minimize the harshness of the disease symptoms!  

When we look for effectiveness of brachytherapy, it plays a vital role in treating lung cancer. But the researchers found out more positive results in treating both cancers that are mesothelioma and lung cancer, when a patient goes through a treatment called permanent brachytherapy. In permanent brachytherapy a radioactive material is put inside the tumor and after few months of span it loses its radioactivity.

Want More Information about Brachytherapy?

By now we already know that brachytherapy is administered by placing a radioactive material, which is called implant. This radioactive material is may be in the form of seed (size of a grain of rice) or a wire.

The implant may be put during the surgery; this technique is called IORT (Intraoperative Radiation Therapy). Other than that, it can be injected into the cancer tissue via hollow tube. When this type of administration is used, a patient will receive general or local anesthesia and then doctors usually take the help of imaging scans like ultrasound and CT scan. As soon as the implant is placed inside the tumor, it attacks the cancer tissue in radius of 1cm. It can easily target the tumor inside, but accuracy is necessary.

Usually brachytherapy is implemented in the combination with other treatments. Moreover, IORT is always administered in conjunction with surgery.

The brachytherapy treatment can also used together with the traditional radiation treatment to attack the growth of tumor in various ways. Brachytherapy can be used as a curative treatment to get rid of mesothelioma cancer, but it largely depends upon the each patient’s condition and treatment. Not only this it can also used as palliative treatment to minimize the harsh symptoms of the disease like breathlessness and coughing, etc.

What are the side-effects of brachytherapy?

When comparing with external beam radiation therapy the side-effects of brachytherapy are quite minimal. Tenderness at the location of insertion is the most common side-effect that goes away within few months. Temporary swelling at the location of the treatment may also occur. While in EBRT, patient may experience nausea, irritation in skin and fatigue.

Now let me discuss the types of Brachytherapy!

Types of Brachytherapy

There are mainly two types of brachytherapy, which are low-dose rate brachytherapy and high-dose rate brachytherapy. Mesothelioma patients are usually treated with permanent brachytherapy; it is a kind of low-dose rate brachytherapy. In permanent brachytherapy it attacks the tumor with the radiation for several months.

The treatment can go up to several weeks depending upon which type of brachytherapy is used. Brachytherapy treatment time is much shorter than EBRT; EBRT takes about 2-10 weeks of treatment time.

Low- Dose Rate Brachytherapy

Low dose of radiation is given in LDR (Low-Dose Rate) for quite a long period of time. Radioactive material is placed for a week in the site. These radiations are very unsafe for the people in close proximity; therefore the patients that are receiving this treatment will be in hospital for the whole duration of the treatment. Moreover, these patients are not allowed to meet any guest and they are kept in private rooms. The good thing about LDR treatment is that it is not painful and uncomfortable.

High-Dose Rate Brachytherapy

High dose of radiation is given for not more than 20 minutes in HDR (High-Dose Rate). In HDR treatment, the patient may undergoes this treatment once or twice a day for a number of weeks. The patient can leave the hospital as soon as the doctor inserts the implant through hollow tube in the place. Like LDR, this treatment is also not painful and uncomfortable.

Study results of Brachytherapy

Only few tests of brachytherapy are being carried out for mesothelioma patients with varying results.

In 2005, 123 cases of pleural mesothelioma were treated with brachytherapy. Then, these patients went through pleurectomy/decortication. The conclusion of these tests was that with or without brachytherapy is not that much effective to stop the growth of mesothelioma tumor.

Brachytherapy is still expected to be one of most promising treatment of mesothelioma regardless of this study. The tests are still going on to prove its effectiveness on mesothelioma and we hope that it will come out as expected!

Intensity-Modulated Radiation Therapy

Primarily Intensity- Modulated Radiation Therapy (IMRT) is used to treat head, neck and prostate cancer, but in some cases IMRT is used in the treatment of mesothelioma and other lung related cancers. IMRT is not the only one radiation therapy used to treat the mesothelioma cancer; there are other two types of radiation therapy too like Brachytherapy and Three-Dimensional Radiation Treatment (3D-CRT) that could be really helpful in the treatment.

How is IMRT done?

A computer- controlled device, linear accelerator, is used by IMRT. This device boosts the speed through which radiation moves along a straight path. It is the linear accelerator that makes it possible to deliver very precise and high-radiation doses to the entire tumor or to the specific parts of the tumor. The accuracy and precision of the device decreases the possibility of damaging the healthy tissues in the surroundings of radiation area. As the ray is released in several small bursts the dose of radiation can adjust more easily to the shape and size of the tumor. As you know the life expectancy for the patients of Mesothelioma is largely depends on the elimination of tumor.

How is IMRT used in treating Pleural Mesothelioma?

Typically in treating pleural mesothelioma three types of treatments are used, which is called trimodality:

• Neoadjuvant chemotherapy (it is done before the main treatment that is surgery)

• Extrapleural pneumonectomy (it is the excision or surgical removal of the affected lung)

• Adjuvant radiation (it is done after the procedure of surgery, in order to destroy any remaining cancer cells)

In IMRT, the radiotherapy plays a very effective role! Toxicity problems are related to this type of radiotherapy; from time to time radiation oncologists assess the effectiveness of it by using imaging scan made by FDG-PET (fluorodeoxyglucose-positron emission tomography).

A radioactive glucose tracer (a substance that has a radioisotope) is used to track the metabolism of glucose in the cancer cells. This is really useful in providing information about whether the cell is responding to the treatment or it is still functional.

Now, let me discuss a form of IMRT, which is Hemithoracic Radiation Therapy!  

Hemithoracic Radiation Therapy

Hemithoracic Radiation targets a particular part of affected chest area. The good thing is that the researchers are finding successful results about applying the high doses of this radiation therapy on number of mesothelioma patients, which were in the advance stages of the disease! 

The median survival rate of the patients who received high dose of hemithoracic radiation is 12.4 months with a one-year survival rate.

What are advantages and disadvantages of IMRT?

The advantage of IMRT is the precision! The high dose of radiation can be given to the tumor without damaging the healthy tissues.

The disadvantage of this therapy is due to some toxicity problem like pneumonitis, which is fatal! In pneumonitis lungs become inflamed and in extreme cases the lungs are damaged because of the tissues within the air sacs, lungs are unable to stretch while breathing. It can cause respiratory failure, heart failure and death. But researchers are trying to eliminate this side-effect and determine how much a patient can tolerate the doses of this radiation.