The effects of radio frequency (MRI)
Introduction
Magnetic resonance imaging (MRI) is a useful medical imaging application utilized by radiologists and clinicians to study anatomical and functional characteristics in healthy and disease states (Elman & Harth, 2011). Scanners used in MRI involve the use of powerful magnetic waves and radio waves that help to create images for interpretation by medical professionals.
It is the preferred medical imaging technique by health providers because it does not involve the use of ionizing radiation. The application is commonly used to facilitate medical diagnosis, estimate stage of a disease or health condition and support patient follow-up (Schwarz et al., 2008; Hartwig et al., 2009).
Radio frequency (RF) waves are used in MRI scanners to excite nuclei that yield energy for imaging of body organs and systems. When conducting MRI, RF waves could come into contact with body tissues and foreign materials like metallic implants. The power produced by RF fields during medical imaging is converted into thermal energy.
The energy is received by neighboring body organs, which are caused to increase their internal and external temperature. While the use of MRI in the healthcare industry to improve patient outcomes has increased rapidly, there have been growing concerns that exposure to RF as used in MRI could result in health problems (Hartwig et al., 2009).
This paper gives the definition and background information of RF. It analyzes biological effects of RF used in MRI in healthcare settings. It also gives a conclusion based on the significant findings on the effects of RF.
Definition and background of RF
A radio frequency field is characterized by electric and magnetic features, and it is part of the electromagnetic spectrum. MRI scanners measure the intensity of RF field by determining the units of magnetic field strength. A volt per meter is used to determine how a magnetic field strength is or strength of magnetic field in terms of current per meter (A/m).
The use of RF has increased both in clinical and non-clinical settings. The advancements in the rates of technological adoption have greatly impacted the increase in the use of RF in MRI across the world.
Other sources of RF outside clinical centers include radio stations, antennas used in television sets, and factories for manufacturing mobile phones (Nakamura, Matsuzaki, Hatta, Nobukuni, Kambayashi & Ogino, 2003; Hartwig et al., 2009).
The extent to which RF affects the body depends on the level of interactions between frequencies and wavelengths associated with RF and body organs. Frequency of RF in MRI is used to refer to the number of oscillations per unit time. Wavelength is used to refer to the distance between energy particles and waves of a RF field (Nakamura et al., 2003).
Body reactions
Several studies have determined the effects of RF on body systems, especially with regard to the activity of biophysical pathways. RF could alter the normal physiological activities of biological systems.
Understanding the effects of RF on body systems is important so that better and safer MRI systems could be developed and adopted in the healthcare industry for diagnostic and other applications (Shellock, 2000).
When thinking about how RF causes effects on body organs through biophysical mechanisms, it would be crucial to note that RF radiation does not cause ionization of body chemicals (i.e. formation of anions and cations).
Therefore, RF radiation does have the ability to disrupt chemical bonds in DNA, a molecule that is important in determining heredity and functions of genes.
Although RF radiation does not have direct biophysical effects, it leads to energy conversions that culminate in high amount of energy within body organs (Shellock, 2000). The effects caused by the energy produced by RF radiation are determined by factors like time of exposure to RF radiation, and distance of an organ from a radiation source.
It has been shown that various frequencies are absorbed at different rates by biological systems. Prolonged exposure to RF radiations could result in worsening of body tissues (Shellock, 2000). Also, the shorter the distance between a radiation source and a tissue the greater the effects caused.
Damage occurs in a tissue because it is not able to get rid of heat energy produced by the RF radiation. Therefore, it is expected that organs that are not deeper in the body like the skin could hardly be affected by RF radiation, other factors like period of exposure and distance from the radiation source held constant.
Blood circulation has also been shown to influence the pace and intensity of RF radiation damage to organs. Tissues that are not well supplied with blood encounter more damages caused by RF radiation than those that are well supplied with blood.
Thus, the eyes could be more susceptible to RF radiation because they are characterized by poor blood supply. Much heating has been blamed for causing infertility in males by affecting the process of forming quality spermatozoa.
Heat blankets caused by RF radiation have been shown to increase chances of fetus developing congenital problems, which may trigger a miscarriage (Mjøen, Sætre, Lie, Tynes, Blaasaas, Hannevik & Irgens, 2006; Shellock, 2000). It has been asserted that thermal effects of RF radiation have the greatest impact on biological systems.
There is limited scientific evidence to link RF radiation with biological effects. However, non-thermal effects have been demonstrated to cause abnormal production of cells, neurological disorders, immune diseases, and reproductive problems (Mjøen et al., 2006).
Allergic effects
Allergic reactions are produced by the body to cause clinical symptoms. This is an important aspect in clinical immunology that seeks to understand the various pathways that are involved in initiation of allergies (Mjøen et al., 2009). Tissue molecules close to RF radiation are excited to vibrate by energy produced by the radiation.
When biological molecules vibrate, they produce energy. Thus, the amount of heat energy within organs is increased. Studies suggest that sources of RF radiation that produce small amounts of radiations could trigger allergy-like reactions, which result in unhealthy states of the body.
This process of facilitating the reactions is known as chemical hypersensitivity. The reactions occur if radiation exposure is above the threshold levels. The levels must be reached to increase organ temperature by a minimum of 10C. Exposure to RF radiation has been shown to result in tiredness and dizziness.
It also causes of skin and alimentary canal problems. In some cases, the conditions could be life-threatening when they are severe. However, research shows that some conditions affecting neurological system are caused by RF radiation pulses rather than continuous exposures.
This could impact the design of MRI scanners. While they should be made in such a way that they do not allow prolonged exposures to RF radiation, the systems should also be designed in a manner that they introduce the least amount of radiation pulses to tissues.
Through the design, threshold amount of radiation that would result in unhealthy body reactions would not be achieved (Mjøen et al., 2009).
Cancer effects
Cancer is a leading killer across the world, and it has no cure. The genesis of cancer has been attributed to changes in the human DNA, which result in abnormal cell growth and multiplication. Increase in cancer diagnoses has caused global concerns.
There haven been issues that human beings are exposed to RF radiations, like those produced by mobile phones, which could cause cancer.
The commonest form of cancer associated with the use of mobile phones is cancer of the brain. In fact, several studies have sounded an alarm that increased exposures to RF radiation could pose threats to the development of various forms of cancer.
RF radiation from microwaves is strongly associated with increased chances of developing cancer. TV sets and radio receivers have also been cited to emit some significant amounts of radiation that would result in carcinogenic states over time.
When conducting analyses to understand the impact of RF radiation on abnormal multiplication of cells, scientists collect data on cancer cases and exposure to devices that emit RF radiation.
Wong and colleagues (2009) determined the effectiveness of using RF ablation technique to enhance colorectal cancer treatment. The researchers reviewed literature on the topic from articles published in peer-reviewed journals. RF is used to stop the spread of colorectal cancer cells to the liver (Wong et al., 2009).
This metastasis has become an issue because about half of colorectal cancer patients are characterized by colorectal cancer that spread to the liver. RF radiation is adopted to stop the spread by killing cells in the affected tissue mass. Special needles are used in the process so that only the affected tissue mass is heated up (Wong et al., 2009).
The heating process damages cancerous cells by facilitating agglutination of DNA and protein molecules (Guler, Tomruk, Ozgur & Seyhan, 2010). The authors conclude that laparoscopic RF is the safest method of killing abnormal cells in the liver because the technique kills the least number of healthy cells in the neighboring tissue, and it could be repeated easily (Guler et al., 2010).
Also, there is no clear difference in benefits of surgical and RF approaches to killing cancer cells in the liver. However, the study authors suggest that studies should be conducted to assess the effectiveness of using RF radiation to remove hepatic metastases.
Since several studies have associated exposures to RF radiation with the development of cancer, there should be evidence-based findings to determine the benefits of using RF in anticancer killing methods.
It could be that RF facilitates cell death in the affected tissue, but it also causes changes in DNA in the surrounding cells, a process that leads to abnormal multiplication of cells (Wong et al., 2009; Guler et al., 2010).
Skin problems and biological system defects
Skin exposures to RF radiation facilitate the development of skin clinical symptoms because the skin reacts negatively when exposed to RF radiation threshold levels (Elman & Harth, 2011). Disease states of biological systems cause malfunctioning of many tissues and organs.
Caution should be taken when exposing organs to RF radiation because prolonged exposures of threshold levels would result in defects (Elman & Harth, 2011). The use of RF radiation in MRI scanning equipment in males causes a major concern. There is evidence that household and personal devices like mobile phones could initiate male reproductive problems.
This could happen when RF radiation interferes with the pathways involved in producing normal sperm count. The changes would lead to pathological modifications in testes that would interfere with the factors crucial in viability and motility of spermatozoa.
If testes are exposed to RF radiation, then they could be affected by oxidative stress, which causes DNA damage in sperms. Health parameters of male sperms are closely monitored by DNA. Thus, DNA damage leads to abnormal sperm cells, a process that culminates in male infertility.
Exposure to RF alters the physiology of seminiferous tubules and lumen that are essential in producing healthy sperms. Continuous exposure to RF radiation could lead to chemical isomerism in the kidneys, a process that could lead to kidney problems.
If persons are exposed to high levels of RF radiation, then they could develop unstable chromosomes. Abnormal chromosomes result in many disease states in an individual. For example, an individual could have an altered growth pattern and development of other biological system defects (Ruediger, 2009).
Research shows that RF radiation exposures of about 50-60Hz could lead to congenital defects, female infertility, and pre-term births, among others. Women who are exposed to household appliances that emit RF have high chances of miscarrying or failing to conceive in life.
The reproduction problems highlighted in this section have important implications for MRI in the healthcare industry. RF radiation should be used selectively in a healthcare facility. Young men and women in the child-bearing ages should not undergo frequent MRI because the procedure could make them develop reproductive problems.
If this group of people has to undergo MRI, then necessary caution and standards should be adopted to ensure that young females and males are prevented from being exposed to harmful RF radiation (Ruediger, 2009).
Neurological, cognitive and hypersensitivity effects
Neurons play important roles in impulse processing and transmission. If their chemical or structural components are affected, then they would not carry out their functions effectively. For example, interfering with the structures of the axons and dendrites would compromise the transmission of nerve impulses.
Also, if RF radiation affects the chemical composition of a chemical synapse, then it would imply that nerve cells would not communicate and exchange their information in the form of chemicals. Alzheimer’s and Parkinson’s diseases are examples of neurological disorders that could result when the nervous system is exposed to threshold levels of RF radiation (Ruediger, 2009).
There is limited evidence to show that cognitive disorders like impaired memory, prolonged reaction time and altered sleep patterns are significantly linked with continuous exposures to RF radiation. However, if enough evidence is established in the future, then it will have implications for MRI in healthcare organizations.
The evidence will inform radiologists, and other healthcare providers to take caution when using MRI in their clients because they could easily develop cognitive disorders, which could impact their lives negatively (Mjøen et al., 2009).
Continuous exposure to RF radiation leads to electromagnetic field hypersensitivity. Thus, if exposure is prolonged, then the affected people would develop neurological problems. Some symptoms of electromagnetic hypersensitivity include lethargy, skin and digestive problems.
Non thermal RF radiation has not been implicated in causing neurological, cognitive and hypersensitivity problems. However, further research in the future with regard to the disorders might implicate this type of radiation. Detailed research in the future would be supported by innovative approaches.
Winter and colleagues (2013) analyzed the changes that could be adopted when developing radio frequency equipment. The study authors aimed to design equipment for imaging patients that could use high magnetic fields. Conventional RF coils cannot be functional without the use of amplifiers and other devices to maintain good heating effects (Winter,et al., 2013).
However, the wavelengths in such equipment would be greater than those found in the brain. This could result in inaccuracies in therapies (Winter,et al., 2013). To overcome this limitation, the study authors proposed to utilize high magnetic fields. They introduced their model to a thorough testing that involved determining temperature changes and stability of the equipment.
The biomechanical material used corresponded to the human brain. The researchers asserted that the designed equipment would be used effectively for imaging patients without the need for extra materials or devices. Spatial and temperature mapping techniques were used to enhance the efficiency of the equipment (Winter,et al., 2013).
The equipment used heat energy economically, and it was characterized by minimal temperature rise on the external surfaces. Therefore, such equipment would be used to image the brain and one would be assured of safety, i.e. the equipment would not cause damage to brain cells and centers responsive for cognitive functions (Ruediger, 2009).
Conclusion and recommendations
MRI use is common in the healthcare industry for clinical and diagnostic applications. RF waves are used in MRI scanners to excite nuclei that yield energy for imaging of body organs and systems. When conducting MRI, RF waves could come into contact with body tissues and foreign materials like metallic implants.
The power produced by RF fields during medical imaging is converted into thermal energy. The energy is received by neighboring body organs, which are caused to increase their internal and external temperature. Advancements in technology have led to better scanning systems that have significantly improved patient outcomes across the world.
However, there are concerns that RF radiations could impact health status of persons undergoing MRI negatively. Based on findings in this report, RF radiation causes major effects in humans. First, it leads to the development of body reactions due to the heat produced by RF radiations.
Second, harmful radiations have been shown to result in allergic reactions that make the body react to its own substances or those which usually cause no harm. Third, several studies have demonstrated that RF radiations are significantly associated with the development of abnormally multiplying cells in the human body.
Fourth, RF radiations have been implicated in the skin and biological system defects. Fifth, there is evidence to support that RF radiation could cause neurological, cognitive and hypersensitivity effects. In conclusion, it is recommended that further research be conducted to determine the effects of RF radiation in areas that lack research evidence.
Also, patients should always be told the merits and demerits of MRI before they would undergo a medical imaging procedure (MRI). This would enable them to make informed decisions regarding MRI.
References
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