Contributions of Physics in Modern Health Science


Physics is the most fundamental physical science. Physics has contributed in all most all scientific streams, but it has contributed to the health science the most. In this age of multidisciplinary collaboration, the physics professionals will have to have a synergistic relation with the experts of other fields to face the ever growing challenges of the modern Health Science.

Physics is the most fundamental physical science. Physics is the study of all physical phenomena in nature. A physical phenomenon is a change that can be reversible or irreversible and that occurs in a body, a matter or a substance in such a way that it does not lose the characteristics or properties of the body, matter or substance. Light, sound, energy, gravity, atmospheric pressure, electricity, radioactivity etc. etc. are examples of physical phenomena. Since its domain of study is very vast, it has had a profound effect on most of the scientific developments in the modern time.

Physics has contributed in all most all scientific streams, but it has contributed to the health science the most. These contributions were but natural if we consider the following basic facts -

  1. Physics provides explanation to every physical phenomenon. If we look at the human body and its components, they can be viewed and measured and altered as any physical objects. If we look at the processes of living animals more closely, we see many physical phenomena like the circulation of blood, blood pressure, maintenance of temperature of the body, auscultation (that is characteristics sounds made by internal organs ) etc.

  2. Over a period of time many physicists enriched the subject with many experimental techniques to verify various theories. Many of the greatest inventions in modern medicine were possible only by importing techniques developed during experimentation in physics labs. Some of these techniques have revolutionized healthcare technologies for imaging the human body and treating dreaded disease like cancer.


Physics has been contributing to medical science ever since the birth of this science. Some physical agents such as sound, heat, pressure and light have been used to diagnose and treat diseases. Many of the techniques used for examining the eye and treating ocular diseases take advantage of the properties of light. Clinical thermometer (used for measuring body temperature), stethoscope (used to hear characteristic sounds made by internal organs), sphygmomanometer (used to measure blood pressure) are the instruments based on the principles of physics. These have been the indispensable tools in healthcare domain for centuries.

The nineteenth century witnessed the development of a lot of physics-based medical technologies. During this century, scientists developed a purely mechanistic approach to physiology, that led to the development of new health care specialties like electrophysiology (the study of the electrical properties of biological cells and tissues), biomechanics (the study of the structure and function of biological systems such as humans, animals, plants, organs, and the cells by means of the methods of mechanics) and ophthalmology (the study that deals with the anatomy, physiology and diseases of eye).

Towards the end of 19th century, the discovery of X - rays and radioactivity brought a revolutionary radiation based diagnosis and treatment. Soon after these discoveries, X-rays and radium were put to therapeutic use. This gave birth to new subjects called Radiology and Medical Physics. Physicist practising Medical Physics are called medical physicist. The medical physicist is employed in hospitals and they are concerned mainly with medical applications of radiation, diagnostic imaging, clinical measurement of radiation and radiological protection.

As mentioned, there are numerous physics based contribution to Health Science field. But, we must mention the following contributions those revolutionised the field of healthcare and enhanced the health standards of the human being on the earth.

1. X-rays Imaging and Computerised Tomography (CT)

X-rays are electromagnetic radiation whose wavelength lies in the range of 1 A to 10 A. Practically from the moment of the discovery of the X-rays, they have been used to see the interior of the human body. These radiations can be used to take photographs (radiographs) of the inside of the body. X-rays are absorbed by dense materials inside the body (like bone) but not lighter substances like tissue. Hence X-rays can show changes in tissues and organs, such as the breasts and lungs. Since X-rays are ionizing radiation, they pose a radiation-induced health hazard. In recent years radiographic images are taken and stored digitally. The improvement in techniques not only reduced unnecessary radiation doses to the patients but also increased the sensitivity of imaging. A mammogram is an X-ray of the breast. It can help to find breast cancer.

In Computerised Tomography, X-rays are emitted from a highly collimated source and detected by a high-resolution solid state detector. The source is moved around the patient's body in a known circular or spiral path, and the X-rays from the different source locations are detected continuously. A powerful computer using mathematical algorithm reconstruct with reasonable precision the three-dimensional density distributions in the form of series of pictures of the body slices. This facilitates to locate the abnormality precisely with its volume. Owing to the recent measures of ensuring health and safety of the patients undergoing CT scans, this modality has become as an important tool for cancer detection. These slices can be used for precise therapy of cancer also.

2. Ultrasound or Sonography : A cost Effective Detection Technique

Contemporary to the discovery of X-rays, another technique of seeing inside the body was developed. This technique was based on using ultrasound i.e. sound waves with a frequency above human hearing range. Ultrasound imaging is a medical application of SONAR (Sonic navigation and ranging) technology developed originally to locate submarines in naval warfare. Typical diagnostic ultrasound (sonographic) scanner operates in the frequency range of 2 to 18 megahertz. The ultrasound scanner has a microphone which gives of sound waves and this microphone is passed over the body. The sound bounces off the organ inside the body and is picked up again by the microphone. The microphone is linked to a computer which turns the reflected sound waves into a picture. A water-based gel is used to couple the ultrasound between the microphone and patient. In this technique, the famous acoustic effect called Doppler Effect can be used to measure the speed of flowing blood. This is useful in diagnosing Heart-related problems as well as loss of flexibility of cardiovascular tissue. This is a cost-effective diagnostic technique with no health-related side effects as in X-rays and CT scanning. This technique is also used for Breast examinations.

3. PET IMAGING

PET stands for Position Emission Tomography. This technique uses short-lived positron-emitting radionuclide (commonly FDG-18) which is a radioactive equivalent of glucose produced in a cyclotron. When FDG-18 is injected into the body of the patient it goes to places where glucose is used for energy. The short-lived FDG-18 decays and emit positrons. These positrons rapidly encounter with electrons in the body and annihilate to produce a pair of photons which move in opposite directions. These photons are captured in special crystals and the 3D images produced with the help of computer techniques. This can show cancers because cancerous tissues use glucose in a different way from normal tissues. This will show up changes in tissues that use glucose as their main source of energy the brain or heart muscle. In a modern PET-CT scanner, 3-D imaging is often accomplished with the aid of CT X-ray scan performed on the patient during the same session, on the same machine. A PET-CT scan can be helpful to diagnose cancer by localising it precisely. PET_CT can show active cancer. It can find out primary cancer. At present, this technique is not a routine diagnostic method owing to the cost.

4. Laser Therapy

The term LASER stands for "Light Amplification by Stimulated Emission of Radiation". Really speaking the technique was developed for war. Some physicists found its applications in healthcare also. A LASER can deliver concentrated energy is a form of finely controllable light beams. Clinicians can use them to perform surgeries which involves less pain and scarring, less blood loss and shorter recuperation time. A LASER is often used for corneal eye surgery to improve vision, removing kidney stones, removing tumours and skin surgery.

5. Radiotherapy or Radiation Therapy

The discovery of X-rays and radioactivity gave birth to radiation therapy or radiotherapy. Radiation therapy has emerged as the most effective therapy for cancer. Soon after its discovery, X-rays were used for therapy of skin lesions. Techniques were evolved to treat deeper tumours with X-rays. The X-ray therapy is known as external radiation therapy. While soon after the discovery of radioactivity the radiation sources like radium were put inside the body cavity near the diseased part. This type of cancer therapy is called Brachytherapy. The discovery of artificial radioactivity produced radioisotopes like Co- 60 and Cs -137, which are used in radiation therapy. In developing countries like ours Co-60 therapy machines are in vogue to treat cancer, but in the developed countries the field of radiation therapy revolutionised after the advent of the linear accelerator. It is sophisticated high energy machine that can deliver a beam of energetic X-ray or electron to treat malignant tumour of cancer. Advanced cancer treatment techniques like 3D CRD (3-D Conformal Radiation Therapy) and IMRT (Intensity Modulated Radiation Therapy) are possible on these machines.

Conclusion

At the present moment, health science is the only field making many signs of progress on so many fronts. Owing to this the field is posing many challenges. These challenges would demand more contributions. In this age of multidisciplinary collaboration, the physics professionals will have to have a synergistic relation with the experts of other fields to face the ever-growing challenges of this science. While doing this they will have to ensure effective implementation of techniques of Physics.


Comments

Author: Natarajan04 Jan 2018 Member Level: Diamond   Points : 5

The well known components of inflammation was described by Celsus, a Roman scholar in 1st century A.D. It is nothing but a list of physical components, change in colour to red (rubor), increase in local temperature (calor) and increase in local size(tumor). This article reminds me of Madame Marie Curie, a noble prize winner who was a physicist and her discovery of radium has transformed the management of many cancers apart from its role in diagnosing diseases.

In fact there are many dedicated courses related to medical physics like (Msc. Medical Physics and Radiation Physics). Physics is also integral in Bio-technology courses.

Today physics is integral to almost all aspects of medicine, apart from those listed, advances in physics and its integration in healthcare has also improved safety for patients, healthcare providers and some professions also.
Medical Physics has also transformed the way medical teaching is imparted at various levels.

If one has the aptitude for physics but doesn't want to be a lab based researcher, they can chose Medical Physics as an exciting career.



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