Radiation: Forms and Medical Use

Radiation is a form of energy which is in the form of beam or particles. These waves have no weight or smell neither do they have charge. Some of them can be seen for example light waves, others can only be detected by special instruments while others can be felt as in the case of heat waves. Radiation can be broadly classified into two ionizing and non-ionizing radiation. Ionizing radiation are high energy radiation which are capable of causing changes to the atoms which are located in through a process known as ionization. These include x-rays, Beta particles, Gamma rays and alpha particles (Drooger et al. 2015). Non–ionizing radiation has less energy and cannot therefore cause changes at atomic level. Examples of non-ionizing radiation include microwaves, laser light and the signal of radios and television (Hansson Mild et al. 2019). Ionizing and non-ionizing radiation find extensive applications in the field of medicine , including areas where students may seek healthcare dissertation help. (Martin & Sutton, 2015). They are majorly used for two purposes which are to diagnose diseases and as therapies for diseases.

Ionizing radiation can be used to diagnose diseases either externally or internally. External application is in the case of radiology while internal application is in the form of nuclear medicine. X-ray imaging can be performed using three techniques which are; radiographic imaging, computerized tomography and fluoroscopic imaging. X-ray imaging is based on the principle of its partial transmission through the body. X-rays interact with body tissues either through absorption or through scattering. The extent of interaction between x-ray and body tissues is dependent on the energy of the x-ray and the tissue density. A key limitation of x-ray imaging is the deposition of some of the radiation which was part of the dose in the patient’s tissues (De La Vega & Hafeli, 2015). Chest radiography is one of the most common uses of x-rays to diagnose disease. It is a basic tool in diagnosing infectious or cancers which affect the lungs. It also provides important information on the cardiovascular system and anatomical structures found in the midline. It can be used to monitor patients who are critically ill. Another example of where x-ray imaging is used in the case of contrast studies. In contrast studies patients are injected with barium or iodine compounds or with compounds of low density such as air in order to improve the contrast in the image produced by the x-ray. This method has found a wide application in imaging the alimentary canal, the spinal cord, the urinary track and gall bladder (Diebold, 2017)

Nuclear medicine refers to a specialization of medicine which uses the properties of the nucleus of nuclides which are either stable or radioactive to check metabolism, physiology or pathology of the body. It involves the injection, ingestion or inhalation of small amounts of radiopharmaceuticals. Non uniform distribution of the radiopharmaceutical occurs in the body and gamma rays are in turn emitted from the different regions (Zimmermann, 2019) The emitted rays are imaged by a gamma camera otherwise referred to as the positron-sensitive scintillation detector. Nuclear medicine is based on the tracer principle and the possible detection of the radioactive elements used without the destruction of the anatomical system which is being studied. The tracer principle states that minute amounts of materials which have particular chemical and physical identities can follow the natural biochemical and physical pathways and can in turn emit radiation which can be detected from outside the body. Some compounds which are used to label tracer elements include; Technetium-99m, thallium-21 and gallium-66. Although this technique produces less sharp images compared to other techniques such as radiology and computerized tomology, its continued use is based on its ability to asses physiological function enabling the assessment of organ function and not only structure. The diseases diagnosed using nuclear medicine include; thyroid carcinoma, coronary artery disease, brain diseases and coronary artery disease. Currently clinical nuclear medicine emphasizes on radioimmunodiagnosis and single photon emission computed tomography abbreviated as SPECT. Radioimmunodiagnosis uses monoclonal antibodies to detect cancers and trace myocardial infarction while SPECT allows for cross-sectional imaging, is sensitive and has a high resolution (Reuz et al. 2018).

The application of ionizing radiation for therapy is also classified into internal and external sources in relation to the patient. The internal sources are therapeutic nuclear medicine and brachytherapy while external sources are oncology and teletherapy. Radiation oncology employs radiation for the palliative or curative care of cancer. The radiation kills the tumor while it shows a limited effect to normal cells. Curative treatment is achieved when the tumor is small and has not metamophozised beyond the primary cell. Additionally the tumor cells should show a selective response to the radiation. Palliative treatment using radiation aims at improving the quality of life a person lives (Yahalom et al. 2015). It achieves this by reducing the amount of pain, controlling bleeding and controlling obstruction caused by the growth of the tumors. Among the cancer treatment or management methods radiation therapy gives the patient the best opportunity of cure while it also preserves the patient’s functionality. Radiation therapy is extensively applied for breast and prostate cancers. An estimated survival rate of ten years has been reported for breast cancer patients who receive radiation therapy while for prostate cancer about 50-70% of all the patients have been found to maintain potency (Baumann et al. 2016).

Internal radiation sources can be used for the treatment of malignant neoplasms. Brachytherapy which is the placement of radionuclides which are sealed into body tissues or cavities is one such application. This method is advantageous since it offers the greatest amount of radiation to the targeted place/tissue (Lin et al. 2019). Brachytherapy has grown to include high dose rates which imply a patient can be healed in just a matter of minutes. It’s advantageous in that it delivers radiation to the target only and does not expose any other person present in the room to radiation. It is majorly applied in the treatment of gynecological malignancies (Zelefsky et al. 2016).

Production of x-rays

The initial step of producing x-rays involves heating a tungsten filament in order to excite its electrons which are then released. This forms the cathode. The electrons are then attracted to the anode also made of tungsten wire. When the electrons hit the tungsten anode their energy is converted into heat energy and x-ray photons. The x-ray photons are released as a beam called an x-ray spectrum. The setup also contains a negatively focusing cup made of molybdenum which is used to direct the electrons to the anode (Moore & Reynolds 1989)

Gamma knife

Gamma rays are utilized in a treatment method known as gamma knife. This method treats brain disorders using 192 beams of radiation and is able to control tumors which are malignant and those which are not malignant. The importance of this is that the radiation is non -invasive and the patient receives treatment and is discharged within a day after which they can resume their normal life (Webber et al. 1980).

Gamma rays are produced from the settling of excited nucleus following radioactive decay of radionuclides. Some radioisotopes that produce gamma rays are uranium, carbon 14 and potassium 40. Artificially gamma rays are obtained through nuclear fission and physics experiments involving high energy. The photons of gamma rays have the highest energy in the entire electromagnetic spectrum. These rays are very penetrative. The ionizing effect of gamma rays occurs through photoelectric effect and pair production. High exposure could cause an immediate damage to body cells and is a potential risk of cancer.

Comparison between gamma knife and x-rays

Producing x-rays involves heating a tungsten filament in order to excite its electrons which are then released. This forms the cathode. The electrons are then attracted to the anode also made of tungsten wire. When the electrons hit the tungsten anode their energy is converted into heat energy and x-ray photons while the production of gamma rays is produced from the settling of excited nucleus following radioactive decay of radionuclides. The principle behind the use of x-rays is its partial transmission through the body while the principle on which gamma knife works is the delivery of a high dose of ionizing radiation through sources of 201 Cobalt-60, causing the radiation to converge at the targeted tumor. X-rays interact with body tissues either through absorption or through scattering. Gamma knife is used to treat tumors, vascular malfunctions and other brain abnormalities and is less invasive than the normal neurosurgery. It is also effective where one is not healthy enough to undergo neurosurgery. X-rays on the other hand is mainly used as a diagnostic tool where it is used to diagnose pneumonia, breast cancer and broken bones.

Magnetic resonance imaging

This is a test that uses a computer, radio waves and magnets to make images of internal organs and tissues of the body. When done on the brain and spinal cord and on bones and joints one of the diseases targeted is cancer. It can also be used to screen for uterine anomalies and diseases of abdominal organs. The use of Magnetic resonance imaging is sensitive to metallic objects and thus a patient undergoing MRI needs to rid themselves of any metallic objects. The advantage of this non- ionizing radiation is that it is non-penetrating and it is also not painful (Brown & Semeka, 2011)

This method is based on the principle that the human body is made up of water which contains protons whose nuclei can become aligned when a magnetic field is applied. A magnetic resonance scanner makes use of a very powerful magnetic field to align the spins of the protons. It also uses radio frequency to make variable magnetic field. When the protons absorb energy from the magnetic field their spins flip. When this magnetic field is turned off the protons return to their normal spin producing a radio signal which is measured by receivers in the scanner making an image (Friedman et al.1998)

One major drawback of this method is that it cannot be used for patients with metallic implants or pacemakers because the implants heat up and can possible cause death. The loud beeping sounds produced by the MRI scanners can cause ear damage if they are not protected (Kirkam et al. 2006)

Infrared thermography

Infrared thermography is a method which detects infrared radiation emitted been emitted from an object; it then converts it to temperature and then produces an image of temperature distribution (Gaussorgues & Chomet 2012).

The principle behind this method is that the human body is homeothermic meaning that it can regulate temperature and generate heat to maintain temperature conditions fit for survival. The skin forms one of the regulatory organs regulating temperature. Temperature measurements have been used over a long time to determine the health condition of a person. Thermometer measurements were used for this purpose. The normal body temperature of the body was found to be 37 degrees. In thermal imaging, body temperature is used to study diseases which can be reflected by a rise in body temperature Such as an inflammation affecting the underlying tissues, reduced or increased blood flow resulting from tissue abnormality (Lahiri et al. 2012).

The advantage of infrared thermography is that infrared is produced from any object whose temperature is above the absolute zero and therefore it is applicable to any field. Another advantage is that the temperature of the object can be measured without the equipment having contact with the body whose temperature is being measured. Another advantage of infrared thermography is that it allows the assessment of a large area at once (Bagavathiappan et al. 2013).

The disadvantages of this technique are it only allows for detection of surface temperatures. The infrared thermograph is very expensive and there is a possible misreading of the readings especially when the temperatures are very close (Lahiri et al. 2012).

Comparison between MRI and infrared thermography

MRI uses radio waves while infrared thermography uses infrared rays. MRI is based on the principle that the human body is made up of water which contains protons whose nuclei can become aligned when a magnetic field is applied. Infrared thermography is based on the principle that the human body is homeothermic meaning that it can regulate temperature and generate heat to maintain temperature conditions fit for survival. The skin forms one of the regulatory organs regulating temperature. MRI makes images of internal organs and tissues of the body while infrared thermography provides temperature readings of the body organs and can be used to check presence of diseases which cause a change in temperature. Both non- ionizing radiations are non-penetrating and are also not painful. In infrared thermography no contact between the instrument and the body is required. It can also be used to provide readings over a large area. MRI is localized on producing only the targeted image and also produces loud sounds which may damage the ears of the patient. MRI cannot be used when one has any metallic implants like pacemakers while Infrared thermography is only limited to surface temperatures ad are also prone to errors occurring from temperature misreading.

Use radiation in diagnosis and treatment of breast cancer

Several methods are employed for the diagnosis of breast cancer. The methods that apply radiation are mammograms, breast ultra sound, breast magnetic imaging and biopsy (McDonald et al. 2016).

X-rays are used for breast cancer to kill cancer cells and avoid the reoccurrence of cancer cells after surgery is done. It is also done for cases of metastatic cancer to relieve the symptoms. Radiation therapy done after lumpectomy has proved to be as effective as a total removal of the affected breast and has significantly reduced the reoccurrence of breast cancer. X-ray radiotherapy has also proved effective after mastectomy to prevent the spread of cancerous cells to other parts of the chest. X-ray radiation has also demonstrated effectiveness where surgery would not be effective for instance when the breast cancer cells are locally advanced like is the case in inflammatory breast cancer. The application of. X-rays are painless and the patient does not remain radioactive after treatment. High-intensity focused ultrasound (HIFU) is non-invasive and can be used for treatment of benign and malignant tissues. The ultrasound beam is transmitted through soft tissue as a high frequency pressure wave. Radiation therapy uses x-rays or photons with high energy to kill cancerous cells. This is so because cancerous cells are more susceptible to radiation compared to normal cells. Treatment x-ray radiation is painless and one doesn’t remain radioactive. External radiation is the most used therapy with few cases of branchytherapy. Radiation therapy is effective for all stages of cancer and can also be used after cancer surgery to remove any remaining tumors and avoid recurrence of the disease. It can also be employed for palliative care. This method of treatment is effective where surgical procedure would be ineffective. Radiation can be used to manage metastatic cancer (Almurshidi & Abu-Nasser, 2018). Side effects of the use of radiation therapy for breast cancer are fatigue, irritation of the skin, swelling of the breast and a change in skin sensation. The application of. X-rays are painless and the patient does not remain radioactive after treatment.

Justification of the use of radiation in medicine

It is impossible for one to claim that a certain type of radiation is completely safe. However radiation therapy has a huge potential in both diagnostic and therapeutic applications and is therefore impossible to put aside from medical practice. This therefore means that there is a risk/benefit equation that is at play. Players in the medical field must therefore find a way to reduce the risks while increasing the benefits. This can be achieved through continuously improving technology, policy and practice. Standardized reference tables for levels of radiation which are acceptable for each procedure should be set at policy levels. Clinicians should also aim at reducing risk to the patient as much as they are looking for quality results (Donya et al. 2015).

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