What is Gamma Camera ?

  

A gamma camera (γ-camera), also called a scintillation camera or Anger camera, is a device used to image gamma radiation emitting radioisotopes, a technique known as scintigraphy. The applications of scintigraphy include early drug development and nuclear medical imaging to view and analyse images of the human body or the distribution of medically injected, inhaled, or ingested radio nuclides emitting gamma rays.

Scintigraphy  ("scint") is the use of gamma cameras to capture         emitted radiation from internal radioisotopes to create two                dimensional images.

SPECT (single photon emission computed tomography) imaging, as used in nuclear cardiac stress testing, is performed using gamma cameras. Usually one, two or three detectors or heads, are slowly rotated around the patient's torso.

Multi-headed gamma cameras can also be used for Positron emission tomography (PET) scanning, provided that their hardware and software can be configured to detect "coincidences" (near simultaneous events on 2 different heads). Gamma camera PET is markedly inferior to PET imaging with a purpose designed PET scanner, as the scintillator crystal has poor sensitivity for the high-energy annihilation photons, and the detector area is significantly smaller technique is useful where the expense and resource implications of a PET scanner cannot be justified.   radioactive  tracer elements present in the organs and tissues imaged

GAMMA CAMERA

CONSTRUCTION

    

        A gamma camera consists of one or more flat crystal planes (or detectors) optically coupled to an array of photomultiplier tubes in an assembly known as a "head", mounted on a gantry. The gantry is connected to a computer system that both controls the operation of the camera and acquires and stores images. The construction of a gamma camera is sometimes known as a compartmental radiation construction.

The system accumulates events, or counts, of gamma photons that are absorbed by the crystal in the camera. Usually a large flat crystal of sodium iodide with thallium doping in a light-sealed housing is used. The highly efficient capture method of this combination for detecting gamma rays was discovered in 1944 by Sir Samuel Curranwhilst he was working on the Manhattan Project at the University of California at Berkeley. Nobel prize-winning physicist Robert Hofstadter also worked on the technique in 1948.

The crystal scintillates in response to incident gamma radiation. When a gamma photon leaves the patient (who has been injected with a radioactive pharmaceutical), it knocks an electron loose from an iodine atom in the crystal, and a faint flash of light is produced when the dislocated electron again finds a minimal energy state. The initial phenomenon of the excited electron is similar to the photoelectric effect and (particularly with gamma rays) the Compton effect. After the flash of light is produced, it is detected. Photomultiplier tubes (PMTs) behind the crystal detect the fluorescent flashes (events) and a computer sums the counts. The computer reconstructs and displays a two dimensional image of the relative spatial count density on a monitor. This reconstructed image reflects the distribution and relative concentration of

SIGNAL PROCESSIN

  Hal Anger developed the first gamma camera in 1957. His original design, frequently called the Anger camera, is still widely used today. The Anger camera uses sets of vacuum tube photomultipliers (PMT). Generally each tube has an exposed face of about 7.6 cm in diameter and the tubes are arranged in hexagon configurations, behind the absorbing crystal. The electronic circuit connecting the photo detectors is wired so as to reflect the relative coincidence of light fluorescence as sensed by the members of the hexagon detector array. All the PMTs simultaneously detect the (presumed) same flash of light to varying degrees, depending on their position from the actual individual event. Thus the spatial location of each single flash of fluorescence is reflected as a pattern of voltages within the interconnecting circuit array.

The location of the interaction between the gamma ray and the crystal can be determined by processing the voltage signals from the photomultipliers; in simple terms, the location can be found by weighting the position of each photomultiplier tube by the strength of its signal, and then calculating a mean position from the weighted positions. The total sum of the voltages from each photomultiplier, measured by a pulse height analyzer is proportional to the energy of the gamma ray interaction, thus allowing discrimination between different isotopes or between scattered and direct photons.

SPATIAL RESOLUTION

 In order to obtain spatial information about the gamma-ray emissions from an imaging subject (e.g. a person's heart muscle cells which have absorbed an intravenous injected radioactive, usually thallium-201 or technetium-99m, medicinal imaging agent) a method of correlating the detected photons with their point of origin is required.

The conventional method is to place a collimator over the detection crystal/PMT array. The collimator consists of a thick sheet of lead, typically 25 to 75 millimetres (1 to 3 in) thick, with thousands of adjacent holes through it. The individual holes limit photons which can be detected by the crystal to a cone; the point of the cone is at the midline center of any given hole and extends from the collimator surface outward. However, the collimator is also one of the sources of blurring within the image; lead does not totally attenuate incident gamma photons, there can be some crosstalk between holes.

Unlike a lens, as used in visible light cameras, the collimator attenuates most (>99%) of incident photons and thus greatly limits the sensitivity of the camera system. Large amounts of radiation must be present so as to provide enough exposure for the camera system to detect sufficient scintillation dots to form a picture.

Other methods of image localization (pinhole, rotating slat collimator with CZT have been proposed and tested; however, none have entered widespread routine clinical use.

The best current camera system designs can differentiate two separate point sources of gamma photons located at 6 to 12 mm depending on distance from the collimator, the type of collimator and radio-nucleide. Spatial resolution decreases rapidly at increasing distances from the camera face. This limits the spatial accuracy of the computer image: it is a fuzzy image made up of many dots of detected but not precisely located scintillation. This is a major limitation for heart muscle imaging systems; the thickest normal heart muscle in the left ventricle is about 1.2 cm and most of the left ventricle muscle is about 0.8 cm, always moving and much of it beyond 5 cm from the collimator face. To help compensate, better imaging systems limit scintillation counting to a portion of the heart contraction cycle, called gating, however this further limits system sensitivity.

APPLICATIONS

used in ct scanning 

· Gamma camera is used to locate cancers, tumours, minor bone fractures, abnormal functioning of organs and other medical problems.

· Iodine -131 is used to detect thyroid (a gland that absorbs iodine) problems.

· Gamma camera give structural and functional image of body organs.

· Body scan.

· Lung scan.

· Kidney function.

· Thyroid uptake.

· Whole Body scan.

  

ADVANTAGES

· The scintillation detector detects efficiently (bcc. high atomic number of iodine).

· Moderate energy resolution.

· Reliable

CONCLUTION

       Gamma camera equipments is a tool used in nuclear medical depletion, to see and analyze or diagnose overview of the human body by detecting the radiation beam from a radio isotope that is inserted the patients body. 

What is Nano-robotics ? In detail

Nano-robotics is the emerging technology field of creating machines or robots whose components are at or close to the microscopic scale of a nanometre (10⁻⁹meters). More specifically, Nano-robotics refers to the nanotechnology engineering discipline of designing and building nano-robots, with devices ranging in size from 0.1-10 micrometer & constructed of nano scale or molecular component. The names nanobots, nano-ids, nanites, nano-machines or nano-mites have also been used to describe these devices currently under research and development.

Nano machines are largely in the research-and-development phase, but some primitive molecular machines have been tested. An example is a sensor having a switch approximately 1.5 nano meters across, capable of counting specific molecules in a chemical sample. The first useful applications of nanomachines might be in medical technology, which could be used to identify and destroy cancer cells. Another potential application is the detection of toxic chemicals, and the measurement of their concentrations, in the environment.

Since nanorobots would be microscopic in size, it would probably be necessary for very large numbers of them to work together to perform microscopic and macroscopic tasks. These nanorobot swarms, both those incapable of replication  and those capable of unconstrained replication in the natural environment

“Nanorobotics” is best described as an emerging frontier, a realm in which robots operate at scales of billionths of a meter. It is the creation of functional materials, devices, and systems through control of matter on the nanometer scale. Viz. we can continue the revolution in computer hardware right down to the level of molecular gates, switches, and wires that are unimaginable.

        We've gotten better at it: we can make more things at lower cost and greater precision than ever before. But at the molecular scale we're still very crude, that’s where “nanotechnology” comes in, at the molecular level

 Nano-robots are the next generation of nano-machines. Advanced nano-robots will be able to sense and adapt to environmental stimuli such as heat, light, sounds, surface textures, and chemicals; perform complex calculations; move, communicate, and work together conduct molecular assembly; and, to some extent, repair or even replicate themselves. Nanotechnology is the science and application of creating objects on a level smaller than 100 nanometres.  The extreme concept of nanotechnology is the "bottom-up" creation of virtually any material or object by assembling one atom at a time.  Although nano-tech processes occur at the scale of nanometres, the materials and objects that result from these processes can be much larger.  Large-scale results happen when nanotechnology involves massive parallelism in which many simultaneous and synergistic nanoscale processes combine to produce a large-scale result.

Many of the nanorobots have very limited processing power with no artificial intelligence as feared by most of us! They have an onboard processor which is capable of only up to 1000 operations per second. Therefore, they possess no threat whatsoever regarding Artificial Intelligence.

Most cellular repair nanorobots do not need more than 10⁶-10⁹ operations/sec of onboard computing capacity to do their work. This is a full 4-7 order of magnitude below true human-equivalent computing at 10 teraflops (~10¹³ operations/sec). Any faster computing capacity is simply not required for most medical nanorobots.

There are various ways by which this technology can be implemented in the field of medicine. Particularly robotics, since the use of robots, can enhance the way we handle the treatment of ailments or diseases to a level where the life expectancy of our race can be increased.

NANO TECHNOLOGY

Nanotechnology is engineering at the molecular (groups of atoms) level. It is the collective term for a range of technologies, techniques and processes that involve the manipulation of matter at the smallest scale (from 1 to 100 nm2). The nanotechnology provides a better future for human life in various fields. In future nanotechnology provides economy, Eco-friendly and efficient technology which removes all difficult predicaments which are faced by us in today life scenario. Nanotechnology is the technology of preference to make things small, light and cheap, nanotechnology based manufacturing is a method conceived for processing and rearranging of atoms to fabricate custom products.

The nanotechnology applications have three different categories nanosystems,  nanomaterials and nanoelectronics. The impact of the nanotechnology occurred on computing and data storage, materials and manufacturing, health and medicine, energy and environment, transportation, national security and space exploration. There are many applications of nanotechnology which are exciting in our life such as nano-powder, nano-tubes, membrane filter, quantum computers etc.

Nanotechnology is not confined to one industry or market. Rather, it is an enabling set of technologies that cross all industry sectors and scientific disciplines. Probably uniquely, it is classified by the size of the materials being developed and used, not by the processes being used or products being produced. Nano science is inherently multidisciplinary: it transcends the conventional boundaries between physics, chemistry, biology, mathematics, information technology, and engineering.

Atoms and molecules stick together because they have complementary shapes that lock together or charges that attract. Just like with magnets, a positively charged atom will stick to a negatively charged atom. As millions of these atoms are pieced together by nanomachines, a specific product will begin to take shape. The goal of molecular manufacturing is to manipulate atoms individually and place them in a pattern to produce the desired structure.

ROBOTICS

Robotics is the branch of technology that deals with the design, construction, operation, and application of robots, well as computer systems for their control, sensory feedback, and information processing. These technologies deal with automated machines that can take the place of humans in dangerous environments or manufacturing processes, or resemble humans in appearance, behavior, and/or cognition. Many of today's robots are inspired by nature contributing to the field of bio-inspired robotics.

The concept of creating machines that can operate autonomously dates back to classical, but research into the functionality and potential uses of robots did not grow substantially until the 20th century. Throughout history, robotics has been often seen to mimic human behavior, and often manage tasks in a similar fashion. Today, robotics is a rapidly growing field, as technological advances continue to research, design, and building new robots serve various practical purposes, whether domestically, commercially, or militarily. Many robots do jobs that are hazardous to people such as defusing bombs, mines and exploring shipwrecks.

At present mostly (lead-acid) batteries are used as a power source. Many different types of batteries can be used as a power source for robots. They range from lead acid batteries which are safe and have relatively long shelf lives but are rather heavy to silver-cadmium batteries that are much smaller in volume and are currently much more expensive. Designing a battery powered robot needs to take into account factors such as safety, cycle lifetime and weight. Generators, often some type of internal combustion engine, can also be used.

WHAT IS NANOROBOTICS?

Nanorobots are the result of the culmination of two technologies: robotics and Nano technology. A nanorobot is a tiny machine designed to perform a specific task or tasks repeatedly and with precision at nanoscale dimensions, that is, dimensions of a few nanometers (nm) or less, where 1 nm = 10^-9 meter. Nanorobots have potential applications in the assembly and maintenance of sophisticated systems. Nanorobots might function at the atomic or molecular level to build devices, machines, or circuits, a process known as molecular manufacturing. Nanorobots might also produce copies of themselves to replace worn-out units, a process called self-replication.

Nanorobots are of special interest to researchers in the medical industry. This has given rise to the field of nanomedicine. It has been suggested that a fleet of nanorobots might serve as antibodies or antiviral agents in patients with compromised immune systems, or in diseases that do not respond to more conventional measures. There are numerous other potential medical applications, including repair of damaged tissue, unblocking of arteries affected by plaques, and perhaps the construction of complete replacement body organs.

A major advantage of nanorobots is thought to be their durability. In theory, they can remain operational for years, decades, or centuries. Nanoscale systems can also operate much faster than their larger counterparts because displacements are smaller; this allows mechanical and electrical events to occur in less time at a given speed.

HARDWARE

The ideal nanobot consists of a transporting mechanism, an internal processor and a fuel unit of some kind that enables it to function. The main difficulty arises around this fuel unit since most conventional forms of robotic propulsion can’t be shrunk to nanoscale with current technology. Scientists have succeeded in reducing a robot to five or six millimeters, but this size still technically qualifies it as a macro-robot.

Nanosensor

Nano-sensors can be any biological, chemical, or surgical sensory points used to convey information about nano-particles to the macroscopic world. Their use mainly includes various medicinal purposes and as gateways to building other nano-products, such as computer chips that work at the nano-scale and nano-robots. Medicinal uses of nano-sensors mainly revolve around the potential of nano-sensors to accurately identify particular cells or places in the body in need. By measuring changes in volume, concentration, displacement, speed, velocity, gravitational, electrical and magnetic forces, pressure, or temperature of cells in a body, nano-sensors may be able to distinguish between and recognize certain cells.

 

Molecular Sorting Rotor

A class of nanomechanical devices capable of binding/releasing molecules from/to solution and transporting these bound molecules against significant gradients.

 Fins

A fin is a surface used for stability and/or to produce lift and thrust or to steer while traveling in water, air, or other fluid media. Nanorobot can move with the help of these fins.

POWER SOURCES IN NANO ROBOTS

There are mainly two power sources used for nanorobots internal power sources and external power sources.

Internal Power Sources

A nanorobot could use the patient's body heat to create power, but there would need to be a gradient of temperatures to manage it. Power generation would be a result of the See beck effect. A capacitor which has a slightly better power-to-weight ratio can also be used.

 External Power Sources

External power sources include systems where the nanorobot is either tethered to the outside world or is controlled without a physical tether. Tethered systems would need a wire between the nanorobot and the power source. The wire would need to be strong, but it would also need to move effortlessly through the human body without causing damage. A physical tether could supply power either by electricity or optically. Experimenting with in Montreal, can either manipulate the nanorobot directly or induce an electrical current in a closed conducting loop in the robot.

 Procedure

The basic idea behind nano-robotics is to manipulate objects at the scale of nanometers. Nano-robots might function at the atomic or molecular level to build devices, machines, or circuits, a process known as molecular manufacturing.

There are basically two approaches followed in implementing nano-robots:

1. The first approach is bio-chip which provides a possible approach to manufacturing nano-robots for common medical applications, such as for surgical instrumentation, diagnosis, and drug delivery. This method for manufacturing on a nanotechnology scale is currently in use in the electronics industry. So, practical nano-robots should be integrated as nano-electronics devices, which will allow tele-operation and advanced capabilities for medical instrumentation.

2. The second approach is self-reconfigurable modular robots also known as Fractal robots. Self-re-configuring robots are also able to deliberately change their own shape by rearranging the connectivity of their parts, in order to adapt to new circumstances, perform new tasks, or recover from damage

WORKING

“When the nano-robot passes through the lung capillaries, O₂ partial pressure is high and CO₂ partial pressure is low, so the on-board computer tells the sorting rotors to load the tanks with oxygen and to dump the CO₂. When the device later finds itself in the oxygen-starved peripheral tissues, the sensor readings are reversed. That is, CO₂ partial pressure is relatively high and O₂ partial pressure relatively low, so the on-board computer commands the sorting rotors to release O₂ and to absorb CO₂.

        Respirocytes mimic the action of the natural hemoglobin-filled red blood cells. But a respirocyte can deliver 236 times more oxygen per unit volume than a natural red cell. This nano-robot is far more efficient than biology, mainly because it's diamond construction permits a much higher operating pressure. (The operating pressure of the natural red blood cell is the equivalent of only about 0.51 ATM, of which only about 0.13 ATM is deliverable to tissues.) So the injection of a 5 cm³ dose of 50% respirocyte aqueous suspension into the bloodstream can exactly replace the entire O₂ and CO₂ carrying capacity of the patient's entire 5,400 cm³ of blood!

Nano-robots inside body

Respirocytes will have pressure sensors to receive acoustic signals from the doctor, who will use an ultrasound-like transmitter device to give the Respirocytes commands to modify their behavior while they are still inside the patient's body. For example, the doctor might order all the Respirocytes to just stop pumping, and become dormant. Later, the doctor might order them all to turn on again.

NANOROBOTICS IN EVERYDAY LIFE

Nanotechnology opens the way towards new production routes, more

efficient, performance and intelligent materials, towards the new design of structures and

related monitoring and maintenance systems.

 Space Technology

There are mainly two applications of nano-robotics in space technology:

1. Swarms

2. Space colonization

 Swarms

Swarms are nano-robots that act in unison like bees. They theoretically act like flexible cloth material and is composed of what is called Bucky Tubes. This cloth will act as strong as diamond. If a nano computer is added to nano-machine a smart cloth is found. The smart cloth could be used to keep astronauts from bouncing around in their own aircraft while they sleep, a problem that arises when autopilot computer fires course correction rockets. This cloth-like material will be able to offset the sudden movements and slowly move the astronauts to their position.

 Space Colonization

Nano-robots can be used in carrying out construction projects in hostile environments.

For example, with a handful of replicating robots, utilizing local material and local energy, it is conceivable that space habitats can be completely constructed by remote control so that habit-ants need only show up their suitcases.

Colonization of space can be done and engineer or group of engineers can check the construction of habitats via telepresents utilizing cameras and sensors created on the surface of the mars by nano bots all form the comfortable confines of earth. Venus could be explored with Nano robots too.

 Electronics

In today’s world very large scale integration is done on the electronic chips. Each chip contains millions of electronic circuits. For a proper functioning, each circuitry must be designed with high percussion. As nanorobots can operate at nano scale fabrication of such chips can be easily done.

Medical

Potential applications for nano-robotics in medicine include early diagnosis and targeted drug-delivery for cancer, arteriosclerosis, blood clots, kidney stones, wounds biomedical instrumentation, surgery, pharmaceutics monitoring of diabetes and health care.

In such plans, future medical nanotechnology is expected to employ nano-robots injected into the patient to perform work at a cellular level. Such nano-robots intended for use in medicine should be non-replicating, as replication would needlessly increase device complexity, reduce reliability, and interfere with the medical mission.

 Treating arteriosclerosis

Arteriosclerosis refers to a condition where plaque builds along the walls of arteries. Nano-robots could conceivably treat the condition by cutting away the plaque, which would then enter the bloodstream.

 Breaking up blood clots

Blood clots can cause complications ranging from muscle death to a stroke. Nano-robots could travel to a clot and break it up. This application is one of the most dangerous uses for nano-robots – the robot must be able to remove the blockage without losing small pieces in the bloodstream, which could then travel elsewhere in the body and cause more problems. The robot must also be small enough so that it doesn't block the flow of blood itself.

 Fighting cancer:

Doctors hope to use nano-robots to treat cancer patients. The robots could either attack tumors directly using lasers, microwaves or ultrasonic signals or they could be part of chemotherapy treatment, delivering medication directly to the cancer site. Doctors believe that by delivering small but precise doses of medication to the patient, side effects will be minimized without a loss in the medication's effectiveness.

Helping the body clot:

One particular kind of nano-robots is the clottocyte or artificial platelet. The clottocyte carries a small mesh net that dissolves into a sticky membrane upon contact with blood plasma. According to Robert A. Freitas, Jr., the man who designed the clottocyte, clotting could be up to 1,000 times faster than the body's natural clotting mechanism. Doctors could use clottocytes to treat hemophiliacs or patients with serious open wounds.

 Parasite Removal:

Nano-robots could wage micro-war on bacteria and small parasitic organisms inside a patient. It might take several nano-robots working together to destroy all the parasites.

Gout:

Gout is a condition where the kidneys lose the ability to remove waste from the breakdown of fats from the bloodstream. This waste sometimes crystallizes at points near joints like the knees and ankles. People who suffer from gout experience intense pain at these joints. A nano-robot could break up the crystalline structures at the joints, providing relief from the symptoms, though it wouldn't be able to reverse the condition permanently.

Cleaning Wounds:

Nano-robots could help remove debris from wounds, decreasing the likelihood of infection. They would be particularly useful in cases of puncture wounds, where it might be difficult to treat using more conventional methods.

TYPES OF NANOROBOTS USING IN HEALTHCARE

· Microbrewery nano-robots:

animated picture of nano-medicine  shutter-stock

 These nano-robots would function similarly to the white blood cells in our bodies, but they are designed to be much faster at destroying bacteria. This type of nano-robots should be able to eliminate bacterial infections in a patient within minutes, as opposed to the weeks required for antibiotics to take effect.

Microbrewery nano-robots are designed so that antibodies attach to the particular bacteria the robot is seeking. After bacteria attaches to an antibody, an arm grabs the bacteria and moves it to the inside of the nano-robot, where it’s destroyed. Bacteria is then discharged into the bloodstream as harmless fragments.

animated picture of cancer treatment nano robot

· Respirocyte nano-robots: These nano-robots would function in a similar way to the red blood cells in our bodies; however, they are designed to carry much more oxygen than natural red blood cells. This design could be very useful for patients suffering from anemia.

These respirocyte nano-robots would contain a tank in which oxygen is held at a high pressure, sensors to determine the concentration of oxygen in the bloodstream, and a valve that releases oxygen when sensors determine that additional oxygen is needed.

· Clottocyte nano-robots: These robots function similarly to the platelets in our blood. Platelets stick together in a wound to form a clot, stopping blood flow. Depending on the size of the wound, significant blood loss can occur before a clot is formed.

A system of clottocyte nano-robots would store fibers until they encounter a wound. At that point, the nano-robots would disperse their fibers, which would then come together to create a clot in a fraction of the time that platelets do.

· Cellular repair nano-robots: These little guys could be built to perform surgical procedures more precisely. By working at the cellular level, such nano-robots could prevent much of the damage caused by the comparatively clumsy scalpel.

SCOPE OF FUTURE WORK

Teams around the world are working on creating the first practical medical nano-robot. Robots ranging from a millimeter in diameter to a relatively hefty two centimeters long already exist, though they are all still in the testing phase of development and haven't been used on people. We're probably several years away from seeing nano-robots enter the medical market. Today's micro-robots are just prototypes that lack the ability to perform medical tasks.

In the future, nano-robots could revolutionize medicine. Doctors could treat everything from heart disease to cancer using tiny robots the size of bacteria, a scale much smaller than today's robots. Robots might work alone or in teams to eradicate disease and treat other conditions. Some believe that semi-autonomous nano-robots are right around the corner -- doctors would implant robots able to patrol a human's body, reacting to any problems that pop up. Unlike acute treatment, these robots would stay in the patient's body forever.

Another potential future application of nano-robot technology is to re-engineer our bodies to become resistant to disease, increase our strength or even improve our intelligence. Dr. Richard Thompson, a former professor of ethics, has written about the ethical implications of nanotechnology. He says the most important tool is communication, and that it's pivotal for communities, medical organizations and the government to talk about nanotechnology now, while the industry is still in its infancy.

Will we one day have thousands of microscopic robots rushing around in our veins, making corrections and healing our cuts, bruises and illnesses? With nanotechnology, it seems like anything is possible.

ADVANTAGE

.RAPID ELIMINATION OF DISEASES

.NO MAINTENANCE

.EASILY DISPOSABLE

.SMALL SIZE

.PAINLESS TREATMENT

DISADVANTAGE

EXPENSIVE TECHNOLOGY

INITIAL DESIGN COST IS HIGH

HARD TO PROGRAM

RISK OF CANCER

SOME TIME ROBOTS GOES OUT OF CONTROL IN HUMAN BODY

CONCLUSION

Nanomedicine will eliminate virtually all common diseases of the 20th century, virtually all medical pain and suffering, and allow the extension of human capabilities most especially our mental abilities.

Consider that a nanostructure data storage device measuring ~8,000 micron³, a cubic volume about the size of a single human liver cell and smaller than a typical neuron, could store an amount of information equivalent to the entire Library of Congress. If implanted somewhere in the human brain, together with the appropriate interface mechanisms, such a device could allow extremely rapid access to this information.

A single nano-computer CPU, also having the volume of just one tiny human cell, could compute at the rate of 10 teraflops (10¹³ floating-point operations per second), approximately equalling (by many estimates) the computational output of the entire human brain. Such a nano-computer might produce only about 0.001 watt of waste heat, as compared to the ~25 watts of waste heat for the biological brain in which the nano-computer might be embedded.

  But, perhaps the most important long-term benefit to human society as a whole could be the dawning of a new era of peace. We could hope that people who are independently well-fed, well-clothed, well-housed, smart, well-educated, healthy and happy will have little motivation to make war. Human beings who have a reasonable prospect of living many "normal" lifetimes will learn patience from experience, and will be extremely unlikely to risk those "many lifetimes" for any but the most compelling of reasons.