Medical physics

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Medical Physics is generally speaking the application of physics concepts, theories and methods to medicine or healthcare. Medical physics departments may be found in hospitals or universities.

In the case of hospital work the term 'Medical Physicist' is the title of a specific healthcare profession with a specific mission statement (see below). Such Medical Physicists are often found in the following healthcare specialties: diagnostic and intervention radiology (also known as medical imaging), nuclear medicine, and radiation oncology (also known as radiotherapy). However, areas of specialty are widely varied in scope and breadth e.g., clinical physiology (also known as physiological measurement, several countries), neurophysiology (Finland), radiation protection (many countries), and audiology (Netherlands).

University departments are of two types. The first type are mainly concerned with preparing students for a career as a hospital medical physicist and research focuses on improving the practice of the profession. A second type (increasingly called 'biomedical physics') has a much wider scope and may include research in any applications of physics to medicine from the study of biomolecular structure to microscopy and nanomedicine.

Mission Statement of the healthcare profession 'Medical Physicist'[edit]

In the case of hospital Medical Physics departments the mission statement is as follows; it is based on a mission statement found here:[1]

“Medical Physicists will contribute to maintaining and improving the quality, safety and cost-effectiveness of healthcare services through patient-oriented activities requiring expert action, involvement or advice regarding the specification, selection, acceptance testing, commissioning, quality assurance/control and optimised clinical use of medical devices and regarding patient risks and protection from associated physical agents (e.g., x-rays, electromagnetic fields, laser light, radionuclides) including the prevention of unintended or accidental exposures; all activities will be based on current best evidence or own scientific research when the available evidence is not sufficient. The scope includes risks to volunteers in biomedical research, carers and comforters. The scope often includes risks to workers and public particularly when these impact patient risk”

The term ‘physical agents’ refers to ionising and non-ionising electromagnetic radiations, static electric and magnetic fields, ultrasound, laser light and any other Physical Agent associated with medical e.g., x-rays in computerised tomography (CT), gamma rays/radionuclides in nuclear medicine, magnetic fields and radio-frequencies in magnetic resonance imaging (MRI), ultrasound in ultrasound imaging and Doppler measurements etc.

This mission includes the following 11 key activities:

1. Scientific problem solving service: Comprehensive problem solving service involving recognition of less than optimal performance or optimised use of medical devices, identification and elimination of possible causes or misuse, and confirmation that proposed solutions have restored device performance and use to acceptable status. All activities are to be based on current best scientific evidence or own research when the available evidence is not sufficient.

2. Dosimetry measurements: Measurement of doses suffered by patients, volunteers in biomedical research, carers, comforters and persons subjected to non-medical imaging exposures (e.g., for legal or employment purposes); selection, calibration and maintenance of dosimetry related instrumentation; independent checking of dose related quantities provided by dose reporting devices (including software devices); measurement of dose related quantities required as inputs to dose reporting or estimating devices (including software). Measurements to be based on current recommended techniques and protocols. Includes dosimetry of all physical agents.

3. Patient safety / risk management (including volunteers in biomedical research, carers, comforters and persons subjected to non-medical imaging exposures. Surveillance of medical devices and evaluation of clinical protocols to ensure the ongoing protection of patients, volunteers in biomedical research, carers, comforters and persons subjected to non-medical imaging exposures from the deleterious effects of physical agents in accordance with the latest published evidence or own research when the available evidence is not sufficient. Includes the development of risk assessment protocols.

4. Occupational and public safety / risk management (when there is an impact on medical exposure or own safety). Surveillance of medical devices and evaluation of clinical protocols with respect to protection of workers and public when impacting the exposure of patients, volunteers in biomedical research, carers, comforters and persons subjected to non-medical imaging exposures or responsibility with respect to own safety. Includes the development of risk assessment protocols in conjunction with other experts involved in occupational / public risks.

5. Clinical medical device management: Specification, selection, acceptance testing, commissioning and quality assurance/ control of medical devices in accordance with the latest published European or International recommendations and the management and supervision of associated programmes. Testing to be based on current recommended techniques and protocols.

6. Clinical involvement: Carrying out, participating in and supervising everyday radiation protection and quality control procedures to ensure ongoing effective and optimised use of medical radiological devices and including patient specific optimization.

7: Development of service quality and cost-effectiveness: Leading the introduction of new medical radiological devices into clinical service, the introduction of new medical physics services and participating in the introduction/development of clinical protocols/techniques whilst giving due attention to economic issues.

8: Expert consultancy: Provision of expert advice to outside clients (e.g., clinics with no in-house medical physics expertise).

9. Education of healthcare professionals (including medical physics trainees: Contributing to quality healthcare professional education through knowledge transfer activities concerning the technical-scientific knowledge, skills and competences supporting the clinically effective, safe, evidence-based and economical use of medical radiological devices. Participation in the education of medical physics students and organisation of medical physics residency programmes.

10. Health technology assessment (HTA): Taking responsibility for the physics component of health technology assessments related to medical radiological devices and /or the medical uses of radioactive substances/sources.

11: Innovation: Developing new or modifying existing devices (including software) and protocols for the solution of hitherto unresolved clinical problems.

Medical Biophysics and Biomedical Physics[edit]

Some education institutions house departments or programs bearing the title "medical biophysics" or "biomedical physics." Generally, these fall into one of two categories: interdisciplinary departments that house biophysics, radiobiology, and medical physics under a single umbrella;[2][3][4] and undergraduate programs that prepare students for further study in medical physics, biophysics, or medicine.[5][6]

Areas of specialty[edit]

The American Association of Physicists in Medicine (AAPM) recognizes 4 major areas of Medical Physics employment and focus.[7] These are:

1. Diagnostic or Imaging Physics and Radiological Sciences[edit]

Para-sagittal MRI of the head in a patient with benign familial macrocephaly.

Clinical (both "in-house" and "consulting") physicists[8] typically deal with areas of testing, optimization, and quality assurance of diagnostic radiology physics areas such as radiographic X-rays, fluoroscopy, mammography, angiography, and computed tomography, as well as non-ionizing radiation modalities such as ultrasound, and MRI. They may also be engaged with radiation protection issues such as Radiation Exposure Monitoring and dosimetry. In addition, many imaging physicists are often also involved with nuclear medicine systems, including single photon emission computed tomography (SPECT) and positron emission tomography (PET).

Sometimes, imaging physicists may be engaged in clinical areas, but for research and teaching purposes,[9] such as e.g. quantifying intravascular ultrasound as a possible method of imaging a particular vascular object.

2. Radiation Oncology or Therapeutic Physics[edit]

The majority of medical physicists currently working in the US, Canada, and some western countries are of this group. A Radiation Therapy physicist typically deals with linear accelerator (Linac) systems on a daily basis, as well as more advanced modalities such as TomoTherapy, Gamma knife, Cyberknife, Proton therapy, and Brachytherapy.

The academic and research side of therapeutic physics may encompass fields such as Boron Neutron Capture Therapy, Sealed source radiotherapy, Terahertz radiation, High intensity focussed ultrasound (including lithotripsy), Optical radiation Lasers, Ultraviolet etc. including photodynamic therapy, as well as nuclear medicine including unsealed source radiotherapy, and Photomedicine, which is the use of light to treat and diagnose disease.

3. Nuclear Medicine[edit]

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 tumours. Five Nobel Laureates have been intimately involved with the use of radioactive tracers in medicine.

Over 10,000 hospitals worldwide use radioisotopes in medicine, and about 90% of the procedures are for diagnosis. The most common radioisotope used in diagnosis is technetium-99, with some 30 million procedures per year, accounting for 80% of all nuclear medicine procedures worldwide.

In developed countries (26% of world population) the frequency of diagnostic nuclear medicine is 1.9% per year, and the frequency of therapy with radioisotopes is about one tenth of this. In the USA there are some 18 million nuclear medicine procedures per year among 311 million people, and in Europe about 10 million among 500 million people. In Australia there are about 560,000 per year among 21 million people, 470,000 of these using reactor isotopes. The use of radiopharmaceuticals in diagnosis is growing at over 10% per year.

Nuclear medicine was developed in the 1950s by physicians with an endocrine emphasis, initially using iodine-131 to diagnose and then treat thyroid disease. In recent years specialists have also come from radiology, as dual CT/PET procedures have become established.

Computed X-ray tomography (CT) scans and nuclear medicine contribute 36% of the total radiation exposure and 75% of the medical exposure to the US population, according to a US National Council on Radiation Protection & Measurements report in 2009. The report showed that Americans’ average total yearly radiation exposure had increased from 3.6 millisievert to 6.2 mSv per year since the early 1980s, due to medical-related procedures. (Industrial radiation exposure, including that from nuclear power plants, is less than 0.1% of overall public radiation exposure.)

4. Radiation Safety, Radiation Protection, and Health Physics[edit]

Areas of research and academic development[edit]

ECG trace

Non-clinical physicists may or may not focus on the above areas from an academic and research point of view, but their scope of specialization may also encompass lasers and ultraviolet systems (such as Photodynamic Therapy), fMRI and other methods for functional imaging as well as molecular imaging, electrical impedance tomography, diffuse optical imaging, optical coherence tomography, and dual energy X-ray absorptiometry.

Physiological measurements have also been used to monitor and measure various physiological parameters. Many physiological measurement techniques are non-invasive and can be used in conjunction with, or as an alternative to, other invasive methods.

Education and training[edit]

In Europe[edit]

The presence of Medical Physicists at Expert level ('Medical Physics Experts') in healthcare in Europe is required by EC Directive 97/43/Euratom. At the moment the European Federation of Organizations for Medical Physics is defining a detailed inventory of learning outcomes for Medical Physics Experts in terms of Knowledge Skills and Competences. In Europe education consists of a first degree in Physics or equivalent, a Masters in Medical Physics and a training Residency. For the latest on the EC funded 'Guidelines on the Medical Physics Expert' project go to the EFOMP website (www.efomp.org)

In North America[edit]

In North America,[10] medical physics training is offered at the bachelor's, master's, doctorate, post-doctorate and/or residency levels. Several universities offer these degrees in Canada and the United States.

As of October 2013, over 70 universities in North America have medical physics graduate programs or residencies that are accredited by The Commission on Accreditation of Medical Physics Education Programs (CAMPEP).[11] The majority of residencies are therapy, but diagnostic and nuclear are also on the rise in the past several years.

Professional certification is obtained from the American Board of Radiology (for all 4 areas), the American Board of Medical Physics (for MRI), the American Board of Science in Nuclear Medicine (for Nuc Med and PET), and the Canadian College of Physicists in Medicine. As of 2012, enrollment in a CAMPEP-accredited residency or graduate program is required to start the ABR certification process. Starting in 2014, completion of a CAMPEP-accredited residency will be required to advance to part 2 of the ABR certification process.[12]

United Kingdom[edit]

From October 2011 as part of the Modernising Scientific Careers scheme, the route to accreditation as a medical physicist in England and Wales is provided by the Scientist Training Programme (STP). This scheme is a three year graduate scheme provided by the National School of Healthcare Science. Entrants are required to have a prior undergraduate degree (1:1 or 2:1) in an appropriate physical science.[13]

The STP involves a part-time MSc in Medical Physics (provided by either King's College London, University of Liverpool or University of Newcastle) in addition to practical training within the National Health Service. Assessment is provided by the completion of competencies and by a final assessment similar to the OSCE undertaken by other clinical staff. Completion of the STP leads to accreditation with the Institute of Physics and Engineering in Medicine (IPEM) and registration as a Clinical Scientist.

Prior to 2011 the training route in the United Kingdom was administered in two parts, and this scheme is still used in Scotland and Northern Ireland[14]). Part I involved limited clinical experience and a full-time MSc in medical physics. Part II involved exclusively clinical experience in which the candidate would produce a portfolio of experience which would be submitted to the Academy for Healthcare Science which (in addition to a viva) would lead to professional accreditation with IPEM.

Legislative and advisory bodies[edit]

See also[edit]

References[edit]

  1. ^ Guibelalde E., Christofides S., Caruana C. J., Evans S. van der Putten W. (2012). Guidelines on the Medical Physics Expert' a project funded by the European Commission
  2. ^ University of Toronto - Department of Medical Biophysics
  3. ^ University of Western Ontario - Department of Medical Biophysics
  4. ^ UCLA Biomedical Physics Graduate Program
  5. ^ Wayne State University - Biomedical Physics Program
  6. ^ Fresno State University - Biomedical Physics Program
  7. ^ http://aapm.org/org/policies/details.asp?id=225&type=PP&current=true
  8. ^ http://aapm.org/medical_physicist/default.asp
  9. ^ http://www.medphys.ca/content.php?sec=1
  10. ^ How does someone become a Medical Physicist?. AAPM. Retrieved on 2011-06-25.
  11. ^ CAMPEP Accredited Graduate Programs in Medical Physics. Campep.org (2011-06-01). Retrieved on 2011-06-25.
  12. ^ IC RP CAMPEP addendum. Theabr.org. Retrieved on 2011-06-25.
  13. ^ [1]. Prospects Graduate Website. Retrieved 2014-03-18
  14. ^ [2]. NHS Careers Website. Retrieved 2014-03-18.

Further reading[edit]

  • Amador Kane, Suzanne (2009). Introduction to Physics in Modern Medicine, Second Edition. CRC Press. ISBN 978-1-58488-943-4. 
  • Khan, Faiz (2003). The Physics of Radiation Therapy. Lippincott Williams & Wilkin. ISBN 978-0-7817-3065-5. 
  • Attix, Frank (1986). Introduction to Radiological Physics and Radiation Dosimetry. Wiley-VCH. ISBN 978-0-471-01146-0. 

External links[edit]