Radiotherapy, Gamma Knife Surgery and Proton Beam Therapy

Radiotherapy

Definition and Application of Radiotherapy

Radiotherapy utilises high-energy ionising radiation to destroy cancer cells by damaging the DNA within these cells.
It can be used alone or in conjunction with surgery or chemotherapy.
Radiation can be delivered from outside the body (external radiotherapy) or from within the body (internal radiotherapy or brachytherapy).

Mechanism of Action in Radiotherapy

The ionising radiation breaks the DNA molecule within the cancer cells, causing them to lose their ability to reproduce and grow.
As time passes, these cells die and the body naturally disposes of them.

Advantages and Limitations of Radiotherapy

Advantages: It’s a localized treatment and can be tailored to the size and shape of the tumor. Some forms also allow very precise targeting.
Limitations: Healthy tissues can be affected leading to side effects, depending on the part of the body being treated.

Gamma Knife Surgery

Introduction to Gamma Knife Surgery

Gamma Knife Surgery is a type of radiosurgery utilised for treating brain disorders. It’s called so due to utilisation of gamma rays.
It’s non-invasive and doesn’t involve any actual cut or opening of the skull.

How Gamma Knife Surgery Works

Around 192 tiny beams of radiation focus on the disease area with high precision.
Each individual ray is fairly weak and harmless to tissues it passes through, but their combined effect at the target is lethal to the diseased cells.

Advantages and Limitations of Gamma Knife Surgery

Advantages: It’s non-invasive, precise, requires no anaesthetic and usually completed within a day.
Limitations: It’s only suitable for certain conditions and for tumours up to a certain size. Requires very accurate diagnosis and treatment planning.

Proton Beam Therapy

Definition and Use of Proton Beam Therapy

Proton Beam Therapy is a type of radiotherapy that uses protons rather than x-rays to kill cancer cells.
Protons cause little damage to tissues they pass through and deliver their dose to the tumor site while sparing the healthy surrounding tissue.

Mechanism of Action in Proton Beam Therapy

The protons discharge their energy at a precise depth in the body, which is calculated according to the type and location of the cancer.
This spares healthy tissue that lies beyond the tumor, which is especially useful in places where all surrounding tissue is vital, like the brain.

Advantages and Limitations of Proton Beam Therapy

Advantages: It gives a lower dose to surrounding healthy tissues, potentially allowing a higher dose to the tumor.
Limitations: It’s expensive and less available than other types of radiotherapy. It’s not beneficial for all types of cancers.

Note: The proper use of these treatments involves detailed understanding of Medical Physics and utmost care should be taken to avoid imprecisions.