Radioactive Implants

Radioactive Implants

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The use of radiation in medicine is not limited to x-rays and radiotherapy using external sources. Another form of radiation therapy is brachytherapy, which is a type of internal radiation therapy.

Brachytherapy involves the implanting of small packets of radiation sources. The implants, which are placed near tumours, help to reduce radiation doses, allowing a more direct exposure of the tumours to the radiation sources.

Radioactive seeds compared to a coin. Their size allows them to be implanted in organs affected by cancer
Radioactive seeds compared to a coin. Their size allows them to be implanted in organs affected by cancer

What are radioactive implants?

Doctors use radioactive implants in a type of radiation therapy called brachytherapy. These implants, which contain radioactive material, can be shaped like needles or small capsules, and are made of materials like iridium, caesium, iodine, and palladium. Depending on the treatment, they might be left near the affected area for a day or just a few minutes. This type of radiation therapy is best for treating tumours that are concentrated in a single mass and have a known location.

Radioactive implants are commonly used to treat prostate, breast, cervical, uterine, rectal, skin, bowel, and eye cancer. If you or someone you know is facing one of these types of cancer, talk to your doctor about whether radioactive implants might be part of the treatment plan.

Types of implants

Doctors use two types of radioactive implants in brachytherapy: interstitial and intracavitary. Intracavitary implants are placed inside natural cavities where the tumour is growing. These implants are temporary and are used to treat and uterine cancer. Interstitial implants, on the other hand, are placed near the tumour inside body tissue. They are helpful when tumours can't be removed because they are close to critical organs. Interstitial implants can be permanent, and the radiation lasts until the isotope decays.

Seeds used to treat prostate cancer

Some other implant procedures include surface (placed over the tissue), intraluminal (inside hollow cavities in organs), and intravascular (inside arteries and veins) treatments.

The physics of radioactive implants

Radioactive implants work by using a radioactive isotope that emits radiation through decay. This emitted radiation is known as ionising radiation, which can modify the electrical bonds of molecules and break their DNA chains. The damage can also be caused by free radicals that react with the DNA, causing more damage to the cell.

There are three types of radiation that cause damage in the cell: gamma, alpha, and beta radiation. Alpha sources are not commonly used because their penetration is very short. Instead, beta and gamma sources are preferred. The radiation is emitted through the decay of a radioactive isotope. If you are undergoing radiation therapy with radioactive implants, your doctor will ensure that the amount of radiation you receive is carefully controlled and monitored to minimise any potential side effects.

Damage to the cancer cells

Cells go through different stages of growth, and those undergoing active division, known as mitosis, are more sensitive to radiation. As cancer cells have a higher growth rate, this type of localised therapy can kill cancer cells faster than healthy ones.

Radiation therapy damages cells through two mechanisms: apoptosis or cell arrest. In apoptosis, the damaged cell activates its self-destruct mechanics, effectively killing itself. This process typically happens to cells that have reached the end of their lifespan and need to die to make space for new tissue. The cell leaves behind an apoptotic body, which is a little sealed sack. In cell arrest, the radiation damages the cell's DNA, causing it to stop dividing and replicating. Over time, the cell will eventually die, but the process is slower than apoptosis.

The process is self-triggered when the cell damage is extensive
The process is self-triggered when the cell damage is extensive

Cell arrest occurs when the cell's reproductive mechanism, also known as cycle arrest, is affected. During this process, the cell stops dividing and multiplying to repair its damaged DNA. If the damage is extensive, such as that caused by radiation, the cell will undergo apoptosis.

In addition to radiation-induced damage, cells can also be damaged by free radicals. Free radicals are molecules that result from the impact of radiation on the water molecules that make up most of the human body. These free radicals are highly reactive, and they can impact the DNA, breaking some of its bonds. This can lead to further damage to the cell, including changes to its genetic code that can potentially lead to cancer. However, the body has natural mechanisms to counteract the damage caused by free radicals, including antioxidants that canize them before they cause harm.

Radioactive implant precautions

In summary, radioactive implants are devices used for brachytherapy, a type of internal radiation therapy used to treat cancer. The implants emit ionizing radiation, which damages the cancer cells' DNA and inhibits their division process, leading to cell arrest and apoptosis. Patients undergoing this treatment may need to be isolated, and medical personnel must take precautions to protect themselves from radiation exposure. With long-term implants, prolonged contact with the treated area is not advised. However, it is unlikely that the radiation will cross all human tissue.

Radioactive Implants

Which treatments involves radioactive implants?

Cancer treatments, such as for prostate cancer, colon cancer, breast cancer, skin cancer, eye cancer, lung cancer, and many others can include radioactive implants as part of the therapy. The implants are used in circumstances where the cancer source is localised and small.

What are radioactive implants?

Radioactive implants are small implants filled with radioactive isotopes. The implants are used in the treatment of cancer by exposing the cancer cells to radiation.

How are radioactive implants used to destroy cancer cells?

The exposition to radiation damages the DNA of the cell by breaking its bonds or by creating free radicals. The damage induces cell arrest. During the arrest, the cell stops its processes of division or multiplication to repair its DNA.If the damage is as extensive as the damage produced by a radiation source, the cell goes into apoptosis, which is the programmed death of cells.

How do radioactive implants work?

Radioactive implants work by emitting radiation (gamma, beta, or alpha). The radiation comes from the decay of a radioactive isotope.

How the radioactive implants damage a cell?

Radioactive implants damage a cell by the direct action of the radiation, which impacts the DNA, or by creating free radicals, which then damage the DNA of the cancer cells.

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