RADIATION IN MEDICAL TECHNOLOGY

Lovedeep Singh* and SS Verma

*M.Sc. (Physics) Final Year studentDepartment of Physics, SLIET, Longowal

*E-mail: lovedeepgehal@gmail.com

Radiation takes many different forms in our natural environment. Radiation is an energy that comes from a source and travel through vacuum or we can say that radiation is a process in which electromagnetic waves travel through a vacuum or any materialistic medium. Light, sound and heat are some types of radiation. Although scientists have only known about radiation since

1890’s, they have a large effect on our daily life. Today in benefit humankind, radiation is used in industry, agriculture and medicine technologies. In addition, radiation has very useful applications in areas like space exploration, law enforcement, geology etc. Light, sound and heat are some types of radiation. We will here discuss about the uses of radiation in medical sciences-

USES OF RADIATION IN MEDICAL TECHNOLOGY

Doctors, Dentists, oncologists use a variety of nuclear materials and procedures to diagnose, monitor and treat a wide assessment of medical conditions in humans. In medicine, mainly ionizing radiations are used. Ionizing radiations are those which can produce charged particles (ions) in matter. The most common uses in medicine are given below –

1. Modern diagnostic radiology: - It assures faster and more precise diagnosis and enables monitoring of a large proportion of diseases. It has been estimated that in about one half of the cases, radiological procedures have substantial effect on the speed of diagnosis. Furthermore, several screening procedures such as menology have been developed which are very beneficial for specific population.

2. Nuclear Medicine:- Nuclear medicine is a branch of medicine that use radioactive substances called radiopharmaceuticals, in the diagnosis and treatment of a range of diseases. These substances are specially developed to be taken up predominantly by one organ or type of cell in the body. Once these pharmaceuticals have logged in the relevant part of the body, a special gamma camera is used to scan your body and take pictures which record the radiation emitting from your body. Nuclear medicine offers unique diagnostic information in oncology, cardiology, endocrinology, neurology, urology and others. Techniques used in nuclear medicine are :-

- Bone scanning- Positron Emission Tomography (PET)- Single Photon Emission Tomography (SPET)- Cardio-vascular imaging – Imaging of heart and blood vessels.

3. Radiation therapy:- It is the treatment using penetrating x-rays or gamma rays on the affected regions of the body to destroy cancer cells. It uses ionizing radiation for treatment. The incidence of cancer is about 40% reflecting long life expectancy. Therapeutic techniques can highly be complex but in order to be effective they must be approached on an indisiplinary basis, requiring effective and harmonics co-operation between radiation oncologists, medical physicists and high qualified techniques. Radiotherapy can be used before surgery to shrink a tumor and make it easier to remove. Appropriate use of radio- therapy saves a millions of lives every year. Depending upon the position of radiation source, different types of treatments are used.

> External beam radiotherapy- External beam radiotherapy is one of the kinds of radiation therapy used for destroying cancer cells. In this therapy the external beam is directed towards the affected part of the patient's body. This beam comprising of high energy particles destroys the cancer cells.

> Proton therapy:- Proton therapy is an advanced facility used for the treatment of cancer. A positively charged particle in the atomic nuclei is called a proton and these are used in proton beam therapy. Proton beam therapy uses a machine called cyclotron which is used to energize protons. Protons are extracted from the cyclotron and directed with magnetic fields to the tumor.

4. Sterilizing equipment:- Gamma rays are high energy electromagnetic waves which are only stopped by thick lead. This means that they can easily pass through medical equipment, such as syringes. As gamma rays pass through the packaging they will inactive viruses and kill remains in a sealed plastic pack it will remain sterile.

5. Tracers: - radioactive tracers are used to investigate a patient’s body without the need for surgery. Gamma emitters and sometimes beta emitters are used. A small amount of radioactive material is put in the body of the patient. The radiographer puts a detector around the body to detect any gamma rays or beta rays particles that pass out of patient’ body.

Radiations can also be used to:-

Determine whether or not organs are functioning normally Show whether the blood supply to heart is adequate Detect cancers at an early stage Determine whether the heart can pump blood adequately Determine the extent of cancer and assess the response of cancer to treatment Identify abnormal brain lesions without exploratory surgery Detect whether the brain is receiving an adequate blood supply and if brain cells

are functioning or not Check whether or not kidneys are functioning normally and whether the stomach

is emptying properly Locate a bone fraction before it can be seen or an x-ray.

Different radiations used for different medical purposes:-

Mainly the following are types of radiation which are used in the medical science:-

1. Gamma rays – Gamma rays are electromagnetic radiation like X-rays, but they have higher energy. Gamma rays or gamma knife is used to kill cancer cells. They are also used to trace pathways such as veins and arteries. As discussed earlier sterilization of equipment is also done by using gamma radiations. These waves are generated by radioactive atoms and by nuclear explosions. Gamma rays can be produced in labs through the process of nuclear collision and also through the artificial radioactivity that accompanies these interactions.

2. X-rays – X-rays pass through the skin but are resistant to bones; this property of x-rays helps in finding any fractures in the patient's body. X-rays are produced in a X-ray machine which has a X-ray tube where the electron gun shoots electrons which hit the target material (tungsten is most widely used as a target element) with a very high velocity. X-rays result from the atomic processes which occur when the target is being hit.

3. Beta rays – Beta radiations are used to detect abnormalities in the body.  Tiny beta capsules can be used to treat cancer. The capsules are injected around the cancer and the beta radiation kills the cancer cells. Also in a process called brachytherapy, beta radioisotopes can be used to irradiate areas inside a patient to prevent the growth of certain tissues. This approach has been used successfully to prevent the clogging of arterial inserts called stens. In addition, the emission of beta particles is used indirectly in medical scanning technique known as positron emission tomography (PET).            

Also ultra-sound and echocardiogram uses sound waves to detect soft tissues problem and to treat muscle damage.

Nuclear medicine waste: - The use of radioisotope for medicine diagnosis and treatment results in the generation of mainly low - level waste. The waste includes paper, rags, tools, clothing and filters which contain small amounts of mostly ‘short lived radioactivity. These types of waste often undergo decay storage for periods of months to a few years before being disposed of at a urban land- fill sites.

Risks in radiation treatment

There obviously are some risks. The magnitude of risk from radiation is dose related with higher amounts of radiation being associated with higher risks. Radiation doses of different sizes delivered at different rates to different parts of body can cause different types of health effects at different times. But, the health benefits of diagnosis, X-ray and nuclear medicine may be accompanied by a generally small risk of deleterious effects. The frequency or intensity of biological effects is dependent upon total energy of radiation absorbed per unit mass of sensitive tissue. The quantity is called absorbed dose and expressed in Gy (Gray). A very high dose to whole body can cause death within weeks. For example, an absorbed dose of 5 gray or more received instantaneously would probably be fatal unless treatments were given. A very high dose to a limited part of the body might not be so fatal but other early effects could occur. For example, an instantaneous absorbed dose of 5 gray to skin probably cause erythema, painful Redding of skin whereas a similar dose to reproductive organs might cause sterility. These effects are called deterministic effects. Nuclear medicines can damage cells. To avoid possible harm to patient, it is important that medical tracers do not stay active in the body for long periods.

So it can be concluded that radiation have a key role in the field of medical and health sciences. Radiation can be used in medical technologies for the welfare of humankind if we take into account the necessary precautions.