Importance of Different radiation in medicine and Pharmacy field

What is radiation ?

Radiation is energy that comes from a source and travels through space and may be able to

penetrate various materials.

Classification :

There are 2 types of radiation. those are non-ionizing & ionizing.

Non-ionizing radiation refers to any type of electromagnetic radiation that does not carry

enough energy per quantum (photon energy) to ionize atoms or molecules. Light, radio, and

microwaves are examples of this type of radiation.

Ionizing radiation is any type of particle or electromagnetic radiation that carries enough

energy to ionize or remove electrons from an atom.

Irradiation is the process by which an object is exposed to radiation. The exposure can originate

from various sources, including natural sources.

Source of Radiation : 2 Major sources.

1. Natural source 2. Human source.

1. Natural source :

Three major sources of naturally occurring radiation are:

i. cosmic radiation (comes from the sun and outer space)

ii. sources in the earth's crust, also referred to as terrestrial radiation (ground, rocks, building materials and drinking water supplies)

iii. sources in the human body, also referred to as internal sources. (Potassium 40)

2. Human Source :

There are various human sources for radiation. Some important sources are mentioned below :

i. Medical radiation sources (x rays)

ii. Consumer products

iii. Atmospheric testing of nuclear weapons

iv. Industrial uses

Importance of radiation in Medical field :

1. Radiology :

The most well known application is using x rays to see whether bones are broken. The broad area of x-ray use is called radiology. Within radiology, we find more specialized areas like mammography, computerized tomography (CT) etc.

Another area of x-ray use is called cardiology—where special x-ray pictures are taken of the heart.

An important application of radiation is Magnetic Resonance Imaging (MRI), which uses powerful magnets and radio waves to create cross-sectional images of organs and

internal structures in the body. It does not use radioisotopes or ionizing radiation, but relies on nuclear magnetic resonance of hydrogen.

2. Prostate cancer : Intensity modulated radiation therapy(IMRT) is used in prostate cancer by using 7 different radiation to target the prostate. The computer can determine the optimal number of beams to

deliver the radiation dose to hit the target and avoid other structures. Also cyber-knife radio-surgery is used where multiple beams are giving from any direction. Thus radiation can help in

the field of prostate cancer.

3. Lung Cancer :

Radiation is also used in the lung cancer. In the treatment lasers are used to line up the beam & patient receives radiation treatment.

4. Cervix cancer :

Cervical cancer is a cancer arising from the cervix. It is due to the abnormal growth of cells that have the ability to invade or spread to other parts of the body. Radiation can be used in the

treatment of cervix cancer too. In the treatment lasers are used to line up the beam & patient receives radiation treatment.

5. Research Reactors:

Radiation are also used in research reactors in various Research work. The research reactors

APSARA, CIRUS and DHRUVA at Trombay are utilized for basic and applied research, isotope production, material testing and training for human resource development.

6. Nuclear medicine :

A subspecialty of oncology (the study and treatment of cancer) is radiation oncology. This is a branch of medicine that uses radiation to provide information about the functioning of a person's specific organs or to treat disease. In most cases, the information is used by physicians to make a quick, accurate diagnosis of the patient's illness. The thyroid, bones, heart, liver and many other organs can be easily imaged, and disorders in their function revealed. In some cases radiation can be used to treat diseased organs, or tumors.

7. Radionuclide therapy (RNT):

Rapidly dividing cells are particularly sensitive to damage by radiation. For this reason,

some cancerous growths can be controlled or eliminated by irradiating the area

containing the growth. External irradiation (sometimes called teletherapy) can be

carried out using a gamma beam from a radioactive cobalt-60 source, though in

developed countries the much more versatile linear accelerators are now being utilized

as a high-energy x-ray source (gamma and X-rays are much the same).

An external radiation procedure is known as the gamma knife radio surgery, and

involves focusing gamma radiation from 201 sources of cobalt-60 sources on a precise

area of the brain with a cancerous tumour. Worldwide, over 30,000 patients are treated

annually, generally as outpatients.

Internal radionuclide therapy is by administering or planting a small radiation source,

usually a gamma or beta emitter, in the target area. Short-range radiotherapy is known

as brachytherapy, and this is becoming the main means of treatment.

Iodine-131 is commonly used to treat thyroid cancer, probably the most successful kind

of cancer treatment. It is also used to treat non-malignant thyroid disorders.

Iridium-192 implants are used especially in the head and breast. This brachytherapy

(short-range) procedure gives less overall radiation to the body, is more localised to the

target tumour and is cost effective.

Treating leukaemia may involve a bone marrow transplant, in which case the defective

bone marrow will first be killed off with a massive (and otherwise lethal) dose of

radiation before being replaced with healthy bone marrow from a donor.

Many therapeutic procedures are palliative, usually to relieve pain. For instance,

strontium-89 and (increasingly) samarium 153 are used for the relief of cancer-induced

bone pain. Rhenium-186 is a newer product for this.

Lutetium-177 dotatate or octreotate is used to treat tumors such as neuroendocrine

ones, and is effective where other treatments fail. Lu-177 is essentially a low-energy

beta-emitter (with some gamma) and the carrier attaches to the surface of the tumor.

A new field is targeted alpha therapy (TAT) or alpha radio immunotherapy, especially

for the control of dispersed cancers. The short range of very energetic alpha emissions

in tissue means that a large fraction of that radioactive energy goes into the targeted

cancer cells, once a carrier such as a monoclonal antibody has taken the alpha-emitting

radionuclide such as Bi-213 to exactly the right places. Clinical trials for leukaemia, cystic

glioma and melanoma are under way. TAT using lead-212 is increasingly important for

treating pancreatic, ovarian and melanoma cancers.

An experimental development of this is boron neutron capture therapy using boron-10

which concentrates in malignant brain tumors. The patient is then irradiated with

thermal neutrons which are strongly absorbed by the boron, producing high-energy

alpha particles which kill the cancer. This requires the patient to be brought to a nuclear

reactor, rather than the radioisotopes being taken to the patient.

8. Biochemical analysis :

It is very easy to detect the presence or absence of some radioactive materials even when they

exist in very low concentrations. Radioisotopes can therefore be used to label molecules of

biological samples in vitro (out of the body). Pathologists have devised hundreds of tests to

determine the constituents of blood, serum, urine, hormones, antigens and many drugs by

means of associated radioisotopes. These procedures are known as radio immuno-assays and,

although the biochemistry is complex, kits manufactured for laboratory use are very easy to use

and give accurate results. In Europe some 15 million of these in vitro analyses are undertaken

each year. 9. Sterilizing :

Gamma irradiation is widely used for sterilizing medical products and supplies such as syringes,

gloves, clothing and instruments, many of which would be damaged by heat sterilization.

Cobalt-60 is the main isotope used, since it is an energetic gamma emitter. Large-scale

irradiation facilities for gamma sterilization are in many countries. Smaller gamma irradiators,

often with Cs-137, are used for treating blood for transfusions and for other medical

applications. 10. Diagnostic radiopharmaceuticals :

Diagnostic radiopharmaceuticals can be used to examine blood flow to the brain,

functioning of the liver, lungs, heart or kidneys, to assess bone growth, and to confirm

other diagnostic procedures. Another important use is to predict the effects of surgery

and assess changes since treatment.

The radioisotope most widely used in medicine is technetium-99m, employed in some

80% of all nuclear medicine procedures – hence some 30 million per year, of which 6-7

million are in Europe, 15 million in North America, 6-8 million in Asia/Pacific (particularly

Japan), and 0.5 million in other regions. It is an isotope of the artificially-produced

element technetium.

Myocardial perfusion imaging (MPI) uses thallium-201 chloride or technetium-99m and

is important for detection and prognosis of coronary artery disease.

For PET imaging, the main radiopharmaceutical is fluoro-deoxy glucose (FDG).The FDG

is readily incorporated into the cell without being broken down, and is a good indicator

of cell metabolism.

In diagnostic medicine, there is a strong trend to using more cyclotron-produced

isotopes such as F-18 as PET and CT/PET become more widely available.

Importance of radiation in Pharmacy field : 1. The Effects of Irradiation on Aqueous Solutions and Suspensions : Most of the effects of irradiation on aqueous solutions, suspensions, and water-containing

pharmaceuticals result from the radiolysis of water by ionization and the excitation effect of high-energy gamma rays. This causes decomposition of active substances and other

ingredients that exist in the pharmaceutical formulation. For this reason, many water-containing pharmaceuticals cannot be sterilized by irradiation. However, as an exception, the

aqueous solutions of chloride and phosphates of alkali elements and alkaline earth elements, lactates, and striates of alkali metals can be sterilized by irradiation. Some solutions such as

insulin and heparin solutions may be sterilized by gamma irradiation by freezing before sterilization. The disadvantages of this application are that it is a long and expensive process.

2. The Effects of Irradiation on Oily Solutions and Ointments :

Oily solutions may be sterilized by either irradiation or heat application. But some vegetative oily solutions. cannot be sterilized by heat due to hydrocarbon formation. Some steroids such

as hydrocortisone acetate, prednisolone, and testosterone propionate; some antibiotics such as neomycin, sodium benzyl peniciline, and tetracycline hydrochloride; and some alkaloids are

more resistant to radiation in their oily matrix form than in their dry powder form. Some synthetic ointment excipients such as PEG, silicon, Vaseline, and paraffin may also be sterilized

by irradiation.

3. The Effects of Irradiation on APIs and Other Ingredients in Solid Form :

Many of the ingredients used in the preparation of pharmaceutical formulations may safely be sterilized in a dry solid state, based on different studies of this issue. Antibiotics are one of the most significant areas of concern, and especially semisynthetic penicillins.

For example, powders of parenteral pharmaceuticals of beta-lactam antibiotics such as flucloxacillin sodium and amoxicillin trihydrate, and cephalosporins such as cefadroxil sodium, cephalexin, and cephotaxim, do not exhibit any degradation and activity loss in

solid-state conditions.

There are also some other antibiotics such as gentamycine, tetracycline hydrochloride, chloramphenicol, and neomycin that do not exhibit any degradation by sterilization with radiation.

Apart from antibiotics, some alkaloids such as neostigmine bromide, pilocarpine, morphine sulfate, atropine sulfate, caffeine, some multivitamins, enzymes such as papain, anesthetics such as Novocaine, and other ingredients such as talc, lactose, and

sodium carboxymethylcellulose are also resistant to radiation in dry powder form. Radiation sterilization is a considerably proper method for powders for injection to

obtain aseptic process.

Antineoplastic, antibacterial, and anti-inflammatory agents are the three main classes of drugs having controlled delivery systems that compose 50% of total radiation sterilizable

drugs.

4. Decontamination of Herbal Raw Materials :

Radiation can also be used for the decontamination of herbal raw materials such as extracts of

belladon, ergot, and gummi arabicum that have a definite microbiological load. Studies show that a low dose rate such as 1 kGy can be sufficient for the decontamination of herbal raw

materials without causing any change in their properties.

5. Sterilization of Packaging Materials :

Packaging materials of pharmaceutical formulations such as aluminum tubes and covers, polyethylene and polystyrene containers, bottles, and gelatin capsules and membranes can also

be sterilized with gamma irradiation. The radio sterilization allows for the use of a variety of different materials for packaging. Generally, rigid containers made of fiberboard, plastic, metal, and glass are observed to be proper for radiation sterilization, but discoloration is generally seen with radio sterilization of glass containers. Although radiation sterilization can be

applied to a variety of packaging materials, it has very few commercial applications, due to relatively higher unit costs and difficult automatic filling. Radiation sterilization can be applied not only to rigid materials but also to aerosol cans, valves, and flexible packaging

materials before filling in aseptic conditions.

Disadvantage of radiation :

(i) Side effect :

For Radiation Therapy:

Diarrhea Fatigue

Hair Loss

Mouth Changes (dry mouth, cavities, bone loss in the jaw)

Nausea and Vomiting

Sexual and Fertility Changes Skin Changes (dryness, itching, peeling, or blistering)

Throat Changes Urinary and Bladder Changes

memory loss, problems doing math, movement problems,

incontinence, trouble thinking, or personality changes. Infertility

Joint Problems

Lymphedema

Headache, Blurry vision

Tenderness, swelling (breast) Cough, Shortness of breath

Earaches, Taste changes

For Chemotherapy:

Anemia Appetite Changes

Bleeding Problems

Constipation Diarrhea

Fatigue (Feeling weak and very tired) Hair Loss (Alopecia)

Infection

Memory Changes

Mouth and Throat Changes

Nausea and Vomiting

Nerve Changes

Pain

Sexual and Fertility Changes

Skin and Nail Changes

Swelling (Fluid retention)

Urination Changes (ii) Radioisotope poisons :

Polonium has about 26 isotopes, all of which are radioactive. And it is 250 billion times

more toxic than hydrocyanic acid.

A gram of Po-210 is about 5000 times as radioactive as a gram of radium – which sets

the standard of activity.

Physical and Chemical Methods for Preventing the Harmful Effects of Radiation :

(i) For decreasing the indirect effects of radiation, such as radiolysis, radical formation, and oxidative degradation, materials should be irradiated under anoxia and at low temperatures, or by using additives. These additives may be antioxidants, radioprotectors, or preservatives designed especially for drugs, which should remain nontoxic and not interfere with the efficacy of the drug due to the use of certain energy transfer systems, OSH containing molecules, or scavengers. (ii) Plasticizers can be used as antirads, which have a relatively smaller chain size, are more active, transfer energy easily, and inactivate oxygen radicals by binding easily.

(iii) Crosslinking agents can also be used as chemical methods for decreasing harmful effects

and degradation. Hindered amines and phenols, phosphatecontaining solids, phosphites, thio-esthers, epoxides, and piperidyl compounds are some of these chemical agents.

(iv) Physical methods can also be utilized for preventing the harmful effects of radiation.

Collision, including the use of polymer mixtures, is the easiest and most commonly used one. Molding, rapid cooling after manufacturing, and quenching are other methods.

Conclusion :

The effect of radiation on pharmaceuticals as well as in the medicine sector is a growing area for both the health industry and the research institutes, as is very well known. The effect of

irradiation on pharmaceuticals can be significant when they are sterilized with gamma radiation or e-beam radiation. Sterilization of pharmaceuticals by gamma radiation or e-beam radiation

affects their stability, depending on the physicochemical properties of the active substances and other ingredients and their physical state, whether solid, liquid, or gas. Although gamma radiation sterilization is an official and a more frequently used technique, e-beam sterilization is a promising process and several researchers are investigating its effects on different drugs and materials. In the medical field, improved medical devices may be produced. Disposable products such as syringes, catheters, blood bags, and transfusion sets may be sterilized by irradiation in their final packed form and with minimum risk of contamination. Recently, a large number of different novel analytical methods have become available for determining even very slight physical and chemical changes, and the harmful effects related to degradation may be easily prevented by the use of antioxidants, preservatives, and radio-protectors such as antirads.