Biomedical Engineering is the application of engineering
principles and design concepts to medicine and biology. This field seeks
to close the gap between
engineering and
medicine: It combines the design and problem solving skills of engineering with medical and biological sciences to improve healthcare
diagnosis,
monitoring and
therapy.
[1]
Biomedical engineering has only recently emerged as its own
discipline, compared to many other engineering fields. Such an evolution
is common as a new field transitions from being an
interdisciplinary
specialization among already-established fields, to being considered a
field in itself. Much of the work in biomedical engineering consists of
research and development, spanning a broad array of subfields (see below). Prominent biomedical engineering applications include the development of
biocompatible prostheses, various diagnostic and therapeutic
medical devices ranging from clinical equipment to micro-implants, common imaging equipment such as
MRIs and
EEGs, regenerative tissue growth, pharmaceutical
drugs and therapeutic biologicals.
Subdisciplines within biomedical engineering
Sometimes, disciplines within BME are classified by their
association(s) with other, more established engineering fields, which
can include:
- Chemical engineering - often associated with biochemical, cellular, molecular and tissue engineering, biomaterials, and biotransport.
- Electrical engineering - often associated with bioelectrical and neural engineering, bioinstrumentation, biomedical imaging, and medical devices. This also tends to encompass Optics and Optical engineering - biomedical optics, imaging and related medical devices.
- Mechanical engineering - often associated with biomechanics, biotransport, medical devices, and modeling of biological systems, like soft tissue mechanics.
Bionics and Biomedical Engineer
Artificial body part replacement is just one of the things that
bionics can do. Concerned with the intricate and thorough study of the
properties and function of human body systems, bionics may be applied to
solve some engineering problems. Careful study of the different
function and processes of the eyes, ears, and other organs paved the way
for improved cameras, television, radio transmitters and receivers, and
many other useful tools. These developments have indeed made our lives
better, but the best contribution that bionics has made is in the field
of biomedical engineering. Biomedical Engineering is the building of
useful replacements for various parts of the human body. Modern
hospitals now have available spare parts to replace a part of the body
that is badly damaged by injury or disease. Biomedical engineers who
work hand in hand with doctors build these artificial body parts.
Biotechnology (see also relatedly
bioengineering)
can be a somewhat ambiguous term, sometimes loosely used
interchangeably with BME in general; however, it more typically denotes
specific products which use "biological systems, living organisms, or
derivatives thereof."
[2]
Even some complex "medical devices" (see below) can reasonably be
deemed "biotechnology" depending on the degree to which such elements
are central to their principle of operation.
Biologics/Biopharmaceuticals (e.g., vaccines, stored blood product),
genetic engineering, and various agricultural applications are some
major classes of biotechnology.
Pharmaceuticals are related to biotechnology in two indirect ways: 1)
certain major types (e.g. biologics) fall under both categories, and 2)
together they essentially comprise the "
non-medical-device" set
of BME applications. (The "Device - Bio/Chemical" spectrum is an
imperfect dichotomy, but one regulators often use, at least as a
starting point.)
Tissue engineering
Tissue engineering is a major segment of
Biotechnology.
One of the goals of tissue engineering is to create artificial organs
(via biological material) for patients that need organ transplants.
Biomedical engineers are currently researching methods of creating such
organs. Researchers have grown solid
jawbones[3] and
tracheas from human stem cells towards this end. Several
artificial urinary bladders actually have been grown in laboratories and transplanted successfully into human patients.
[4]
Bioartificial organs, which use both synthetic and biological
components, are also a focus area in research, such as with hepatic
assist devices that use liver cells within an artificial bioreactor
construct.
[5]
Micromass cultures of C3H-10T1/2 cells at varied oxygen tensions stained with
Alcian blue.
Genetic engineering
Genetic engineering, recombinant DNA technology, genetic
modification/manipulation (GM) and gene splicing are terms that apply to
the direct manipulation of an organism's genes. Genetic engineering is
different from traditional breeding, where the organism's genes are
manipulated indirectly. Genetic engineering uses the techniques of
molecular cloning and transformation to alter the structure and
characteristics of genes directly. Genetic engineering techniques have
found success in numerous applications. Some examples are in improving
crop technology (not a medical application per se; see
BioSystems Engineering),
the manufacture of synthetic human insulin through the use of modified
bacteria, the manufacture of erythropoietin in hamster ovary cells, and
the production of new types of experimental mice such as the oncomouse
(cancer mouse) for research.
Neural engineering
Neural engineering
(also known as Neuroengineering) is a discipline that uses engineering
techniques to understand, repair, replace, or enhance neural systems.
Neural engineers are uniquely qualified to solve design problems at the
interface of living neural tissue and non-living constructs.
Pharmaceutical engineering
Pharmaceutical Engineering is sometimes regarded as a branch of biomedical engineering, and sometimes a branch of
chemical engineering;
in practice, it is very much a hybrid sub-discipline (as many BME
fields are). Aside from those pharmaceutical products directly
incorporating biological agents or materials, even developing chemical
drugs is considered to require substantial BME knowledge due to the
physiological interactions inherent to such products' usage. With the
increasing prevalence of "combination products," the lines are now
blurring among healthcare products such as drugs, biologics, and various
types of devices.
Medical devices
This is an
extremely broad category -- essentially covering all health care products that do
not
achieve their intended results through predominantly chemical (e.g.,
pharmaceuticals) or biological (e.g., vaccines) means, and do not
involve metabolism.
A medical device is intended for use in:
- the diagnosis of disease or other conditions, or
- in the cure, mitigation, treatment, or prevention of disease,
Two different models of the C-Leg prosthesis
Some examples include
pacemakers,
infusion pumps, the
heart-lung machine,
dialysis machines,
artificial organs,
implants,
artificial limbs,
corrective lenses,
cochlear implants,
ocular prosthetics,
facial prosthetics, somato prosthetics, and
dental implants.
Stereolithography is a practical example of
medical modeling
being used to create physical objects. Beyond modeling organs and the
human body, emerging engineering techniques are also currently used in
the research and development of new devices for innovative
therapies,
treatments,
patient monitoring, and early
diagnosis of complex diseases.
Medical devices are regulated and classified (in the US) as follows (see also
Regulation):
- Class I devices present minimal potential for harm to the user and
are often simpler in design than Class II or Class III devices. Devices
in this category include tongue depressors, bedpans, elastic bandages,
examination gloves, and hand-held surgical instruments and other similar
types of common equipment.
- Class II devices are subject to special controls in addition to the
general controls of Class I devices. Special controls may include
special labeling requirements, mandatory performance standards, and postmarket surveillance.
Devices in this class are typically non-invasive and include x-ray
machines, PACS, powered wheelchairs, infusion pumps, and surgical
drapes.
- Class III devices generally require premarket approval (PMA) or
premarket notification (510k), a scientific review to ensure the
device's safety and effectiveness, in addition to the general controls
of Class I. Examples include replacement heart valves, hip and knee
joint implants, silicone gel-filled breast implants, implanted
cerebellar stimulators, implantable pacemaker pulse generators and
endosseous (intra-bone) implants.
Medical imaging
Medical/biomedical imaging is a major segment of
medical devices.
This area deals with enabling clinicians to directly or indirectly
"view" things not visible in plain sight (such as due to their size,
and/or location). This can involve utilizing ultrasound, magnetism, UV,
other radiology, and other means.
Imaging technologies are often essential to medical diagnosis, and
are typically the most complex equipment found in a hospital including:
Implants
An implant is a kind of medical device made to replace and act as a
missing biological structure (as compared with a transplant, which
indicates transplanted biomedical tissue). The surface of implants that
contact the body might be made of a biomedical material such as
titanium, silicone or apatite depending on what is the most functional.
In some cases implants contain electronics e.g. artificial pacemaker and
cochlear implants. Some implants are bioactive, such as subcutaneous
drug delivery devices in the form of implantable pills or drug-eluting
stents.
Clinical engineering
Clinical engineering is the branch of biomedical engineering dealing with the actual implementation of
medical equipment and technologies in hospitals or other clinical settings. Major roles of clinical engineers include training and supervising
biomedical equipment technicians (BMETs),
selecting technological products/services and logistically managing
their implementation, working with governmental regulators on
inspections/audits, and serving as technological consultants for other
hospital staff (e.g. physicians, administrators, I.T., etc.). Clinical
engineers also advise and collaborate with medical device producers
regarding prospective design improvements based on clinical experiences,
as well as monitor the progression of the state-of-the-art so as to
redirect procurement patterns accordingly.
Their inherent focus on
practical implementation of technology has tended to keep them oriented more towards
incremental-level
redesigns and reconfigurations, as opposed to revolutionary research
& development or ideas that would be many years from clinical
adoption; however, there is a growing effort to expand this time-horizon
over which clinical engineers can influence the trajectory of
biomedical innovation. In their various roles, they form a "bridge"
between the primary designers and the end-users, by combining the
perspectives of being both 1) close to the point-of-use, while 2)
trained in product and process engineering. Clinical Engineering
departments will sometimes hire not just biomedical engineers, but also
industrial/systems engineers to help address operations
research/optimization, human factors, cost analysis, etc. Also see
safety engineering for a discussion of the procedures used to design safe systems.
A point of reference for clinical engineers would be the catalogue published by the
American Society for Hospital Engineering in the Hospital Engineering Reference Series called
Maintenance Management for Medical Equipment.
Regulatory issues
Regulatory issues are of particular concern to a biomedical engineer;
it is among the most heavily-regulated fields of engineering, and
practicing biomedical engineers must routinely consult and cooperate
with regulatory law attorneys and other experts. The Food and Drug
Administration (FDA) is the principal healthcare regulatory authority in
the United States, having jurisdiction over medical
devices, drugs, biologics, and combination products. The paramount objectives driving policy decisions by the FDA are
safety and
efficacy of healthcare products.
[citation needed]
In addition, because biomedical engineers often develop devices and
technologies for "consumer" use, such as physical therapy devices (which
are also "medical" devices), these may also be governed in some
respects by the
Consumer Product Safety Commission.
The greatest hurdles tend to be 510K "clearance" (typically for Class 2
devices) or pre-market "approval" (typically for drugs and class 3
devices).
Implants, such as
artificial hip joints, are generally extensively regulated due to the invasive nature of such devices.
Most countries have their own particular mechanisms for regulation,
with varying formulations and degrees of restrictiveness. In most
European countries, more discretion rests with the prescribing doctor,
while the regulations chiefly assure that the product operates as
expected. In European Union nations, the national governments license
certifying agencies, which are for-profit companies. Technical
committees of engineers write recommendations which incorporate public
comments, and these can be adopted as regulations by the
European Union.
These recommendations vary by the type of device, and specify tests for
safety and efficacy. Once a prototype has passed the tests at a
certification lab, and that model is being constructed under the control
of a certified quality system, the device is entitled to bear a
CE mark, indicating that the device is believed to be safe and reliable when used as directed.
The different regulatory arrangements sometimes result in particular
technologies being developed first for either the U.S. or in Europe
depending on the more favorable form of regulation. While nations often
strive for substantive harmony to facilitate cross-national
distribution, philosophical differences about the
optimal extent
of regulation can be a hindrance; more restrictive regulations seem
appealing on an intuitive level, but critics decry the tradeoff cost in
terms of slowing access to life-saving developments.
Training and certification
Education
Biomedical engineers require considerable knowledge of both
engineering and biology, and typically have a Master's (M.S., M.S.E., or
M.Eng.) or a Doctoral (Ph.D.) degree in BME (Biomedical Engineering) or
another branch of engineering with considerable potential for BME
overlap. As interest in BME increases, many engineering colleges now
have a Biomedical Engineering Department or Program, with offerings
ranging from the undergraduate (B.S., B.Eng or B.S.E.) to doctoral
levels. As noted above, biomedical engineering has only recently been
emerging as
its own discipline rather than a cross-disciplinary
hybrid specialization of other disciplines; and BME programs at all
levels are becoming more widespread, including the
Bachelor of Science in Biomedical Engineering which actually includes so much biological science content that many students use it as a "pre-med" major in preparation for
medical school. The number of biomedical engineers is expected to rise as both a cause and effect of improvements in medical technology.
[6]
In the U.S., an increasing number of
undergraduate programs are also becoming recognized by
ABET as accredited bioengineering/biomedical engineering programs. Over 65 programs are currently accredited by ABET.
[7][8]
In Canada and Australia, accredited graduate programs in Biomedical Engineering are common, for example in Universities such as
McMaster University, and the first Canadian
undergraduate BME program at
Ryerson University offering a four year B.Eng program.
[9][10][11][12] The Polytechnique in Montreal is also offering a bachelors's degree in biomedicale engineering.
As with many degrees, the reputation and ranking of a program may
factor into the desirability of a degree holder for either employment or
graduate admission. The reputation of many undergraduate degrees are
also linked to the institution's graduate or research programs, which
have some tangible factors for rating, such as research funding and
volume, publications and citations. With BME specifically, the ranking
of a university's hospital and medical school can also be a significant
factor in the perceived prestige of its BME department/program.
Graduate education
is a particularly important aspect in BME. While many engineering
fields (such as mechanical or electrical engineering) do not need
graduate-level training to obtain an entry-level job in their field, the
majority of BME positions do prefer or even require them.
[13] Since most BME-related professions involve scientific research, such as in
pharmaceutical and
medical device
development, graduate education is almost a requirement (as
undergraduate degrees typically do not involve sufficient research
training and experience). This can be either a
Masters or
Doctoral
level degree; while in certain specialties a Ph.D. is notably more
common than in others, it is hardly ever the majority (except in
academia). In fact, the perceived need for some kind of graduate
credential is so strong that some undergraduate BME programs will
actively discourage students from majoring in BME without an expressed
intention to also obtain a masters degree or apply to medical school
afterwards.
Graduate programs in BME, like in other scientific fields, are highly
varied, and particular programs may emphasize certain aspects within
the field. They may also feature extensive collaborative efforts with
programs in other fields (such as the University's Medical School or
other engineering divisions), owing again to the interdisciplinary
nature of BME. M.S. and Ph.D. programs will typically require applicants
to have an undergraduate degree in BME, or
another engineering discipline (plus certain life science coursework), or
life science (plus certain engineering coursework).
Education in BME also varies greatly around the world. By virtue of
its extensive biotechnology sector, its numerous major universities, and
relatively few internal barriers, the U.S. has progressed a great deal
in its development of BME education and training opportunities. Europe,
which also has a large biotechnology sector and an impressive education
system, has encountered trouble in creating uniform standards as the
European community attempts to supplant some of the national
jurisdictional barriers that still exist. Recently, initiatives such as
BIOMEDEA have sprung up to develop BME-related education and
professional standards.
[14] Other countries, such as Australia, are recognizing and moving to correct deficiencies in their BME education.
[15]
Also, as high technology endeavors are usually marks of developed
nations, some areas of the world are prone to slower development in
education, including in BME.
Licensure/certification
Engineering licensure in the US is largely optional, and rarely
specified by branch/discipline. As with other learned professions, each
state has certain (fairly similar) requirements for becoming licensed as
a registered
Professional Engineer
(PE), but in practice such a license is not required to practice in the
majority of situations (due to an exception known as the private
industry exemption, which effectively applies to the vast majority of
American engineers). This is notably not the case in many other
countries, where a license is as legally necessary to practice
engineering as it is for law or medicine.
Biomedical engineering is regulated in some countries, such as
Australia, but registration is typically only recommended and not
required.
[16]
In the UK, mechanical engineers working in the areas of Medical Engineering,
Bioengineering or Biomedical engineering can gain
Chartered Engineer status through the
Institution of Mechanical Engineers. The Institution also runs the Engineering in Medicine and Health Division.
[17]
The
Fundamentals of Engineering exam
- the first (and more general) of two licensure examinations for most
U.S. jurisdictions—does now cover biology (although technically not
BME). For the second exam, called the Principles and Practices, Part 2,
or the Professional Engineering exam, candidates may select a particular
engineering discipline's content to be tested on; there is currently
not an option for BME with this, meaning that any biomedical engineers
seeking a license must prepare to take this examination in another
category (which does not affect the actual license, since most
jurisdictions do not recognize discipline specialties anyway). However,
the Biomedical Engineering Society (BMES) is, as of 2009, exploring the
possibility of seeking to implement a BME-specific version of this exam
to facilitate biomedical engineers pursuing licensure.
Beyond governmental registration, certain private-sector
professional/industrial organizations also offer certifications with
varying degrees of prominence. One such example is the Certified
Clinical Engineer (CCE) certification for Clinical engineers.
