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From a practical clinical perspective discount viagra plus 400 mg otc impotence medication, compliance with these standards ensures that: Just culture • patient information is accurate and up to date • there is compliance with the law • confidentiality is respected • clinical and operational information is used to monitor order viagra plus 400 mg free shipping erectile dysfunction heart attack, plan and improve the quality of patient care • full and appropriate use of the data is made to support clinical Figure 36 cheap viagra plus 400 mg without a prescription erectile dysfunction uti. The most striking feature of high-reliability organi- zations is their collective preoccupation with the possibility of failure – at individual and system level. They maintain a mindset of ‘intelligent wariness’, expecting errors to happen and training Integrity Availability their personnel to recognize and recover them. An effective clin- ical governance framework should be seen as one component in maintaining that ‘intelligent wariness’. Many aspects of the pillars of clinical gov- ernance described here relate to organizational processes rather Figure 36. In the pursuit of clinical excellence, clin- icians should consider how they might both support organizational Confidentiality and data protection can often be perceived as governance and apply these principles to their own clinical practice. In fact, compliance with information governance and medical record standards often Tips from the field allows greater access and use! Sharing knowledge can detailed patient follow up information within a few days of the prevent future morbidity and mortality. In return, the hospital could access detailed prehospital information for its trauma register. Implementing clinical governance: turning vision ing high standards of care by creating an environment in which into reality. Clin Govern Int J 2009;14: can be applied to all healthcare organizations irrespective of oper- 24–37. Clinical governance in pre-hospital vided, organized and managed in a manner which reliably supports care. When to disclose patient information Justice being fair and equitable • How to approach patient’s end of life decision-making. Resilience having the quality of hardiness; ability to be tough and bounce back Respect positive feeling of esteem for oneself and others Teamwork working with others toward common goals Ethics, morals and law Wisdom holding deep understanding of people, events and Everyone comes to their profession with their own personal beliefs situations Tolerance having a fair, objective and permissive attitude toward regarding right and wrong. These ideas are based on a lifetime others who may be different than oneself of learning, experience and exposure to people and values. These Trustworthy being reliable; deserving of another’s confidence beliefs are called ‘morals’. When you enter a profession, you must be aware that your morals may sometimes be challenged by law and professional ethics. In fact, in addition, to your clinical skills when you may not have a clear answer. Good ethics draws on the and knowledge you are obligated to know health-related laws and values important to a profession (Table 37. This chapter aims to help you to refine your skills and understanding in making professional Ethical decision-making ethical decisions. Laws are rules which specific societies impose upon themselves As a healthcare provider, you must know the legal requirements and which are enforced by the government. Laws con- of behaviour which all citizens and visitors to that jurisdiction are cerning the delivery of health care vary significantly from country to obligated to follow and are enforced by the state through criminal country and even from city to city. In general, there are three areas of law that what you absolutely cannot do and the minimum that you are you need to know: required to do. Ethics is a social and applied skill where one looks at the right 1 Criminal law – offences against the state. Charges are usually and wrong of a situation and makes well-reasoned, rational choices. Ethics introduces you to the skills you need to ernments and may be revoked at any time. The state delegates make critical evaluations of complex problems and to be effective self-governance to professionals including the authority to certify those qualified to practice and the authority to revoke a license for violations of professional standards. Preventing and limiting harm to Goodness; excellence; character The injury can be physical or psychological in nature. What is your desired outcome for this an ethical dilemma – a situation in which two or more values Does a proposed course of action patient in this situation? Different health professions rely on different tools when keep you safe from harm? What are your options to lead to the Does a proposed course of action go desired outcome? Medical ethics is based on Has the patient’s privacy been If you do not, have you received deontology (the idea that what is right is strictly following the rule) respected and protected? Whendealingwithanethicaldilemmainaprehospitalemergency situation, you should consider four principles to guide your thought Dignity Fairness process: Treat all individuals with respect To treat all people justly and equally. Have you treated your patient as you To distribute scarce resources in a 1 safety or preventing harm to yourself or others would want to be treated? Have you met the physical and race, religion, sexual orientation, emotional needs of the patient? Have all co-workers been treated completed that task, you can ask which of these principles is the If yes, did the patient consent or equally according to their ability primary one at issue in this case. Then you can use the identified principle to guide If no, is someone with the legal Have you applied triage without bias, authority to make a decision if necessary? Have you followed all rules, laws, and Is the patient at risk of death or policies? In general, on-duty prehospital emergency medical personnel have an obligation to treat patients who are in need of their services. If you are off-duty then you may have an ethical duty to provide care Ingeneral,youdonothavethefreedomtopickandchoosewhom if no one else is around, or if help is not available in a reasonable to treat. If a person laws which prohibit discrimination in the providing of health care is in imminent harm (i. Even if there is you may have an ethical imperative to provide assistance even if you no legal requirement regarding discrimination, ethics requires you lack the above conditions. Your legal obligations vary considerably to treat all patients who require your services. He is wearing torn Spain), however, everyone is obligated to provide help to people in and dirty clothes, appears malnourished, and has not bathed in need. He appears to be the victim of an assault as he is Once you have a patient under your care you cannot cease treat- bleeding from a 10 cm laceration on his scalp and is unconscious. He does not respond to commands and to abandon your patient which is legally and ethically unacceptable. The assumption that all adults can A health care provider’s A patient giving permission to receive treatment or be examined. Then under virtue, you should assess the patient and coercion legal parent/ guardian • Expresses the choice demands care, then come up with a care plan. Third, under dignity, you must assess verbally or in writing care should be given whether the patient has status and ability to make decisions while keeping fairness in mind (Table 37. Since the patient is unconscious and appears to be in need of immediate care he lacks the ability to consent to treatment Table 37.

With the rib cage in exhalation discount viagra plus online amex erectile dysfunction at the age of 20, Muscles commonly considered short and tight in the the thoracic spine moves into sagittal flexion and cheap viagra plus online mastercard condom causes erectile dysfunction, layered syndrome are as follows: across time generic 400mg viagra plus erectile dysfunction psychological causes, may develop an extension restriction due • Hamstrings to contracture of the anterior longitudinal ligament, • Gluteus maximus among other structures. The protraction of the shoul- ders, with or without thoracic extension restriction, • Thoracolumbar erectors disrupts the optimal instantaneous axis of rotation of • Upper fibers of trapezius the glenohumeral joint, and may result in impinge- • Suboccipitals. From the left: optimal posture, layered syndrome, layered syndrome with a sway, lower-crossed and upper crossed syndromes, lower and upper crossed syndromes with a sway Muscles commonly considered to be long and weak workplace. This may hold very little truth, but also in the layered syndrome are as follows: should be put into the context of evolution. Since chairs are known to have been used since 8000 bc • Hip flexors (rectus femoris and iliopsoas) (Cranz 2000) and it takes somewhere in the region of • Lumbar erectors 100 000 years for the human genome to change by • Thoracic erectors 0. Osteokinematically, the pelvis is posteriorly tilted, How the body does adapt is by changing its length– and the lumbar spine is flat with extension at the tho- tension relationships about the pelvis and trunk, the racolumbar junction leading into a thoracic kyphosis most common clinical adaptation being one towards and forward head posture. As the rib cage approximates the posture of the upper quarter is very similar to – and, in pelvis, so the anterior oblique slings (of anterior inter- some cases, indistinguishable from – an upper crossed nal oblique fibers through the linea alba to the contra- syndrome (see Fig. Reciprocally, the lumbar erector group will held in relative extension (and therefore may feel and be held in a lengthened position. Consequently, this posture is commonly a laying down of sarcomeres in a muscle that is held associated with lumbar disc injury clinically. Another example is the office worker who likes to Term Definition spend her weekends playing hockey. She must train her body to survive the relentless load of gravity on Creep The slow movement of a material that her back and neck during her seated work hours and becomes viscous due to shear stresses still be well conditioned enough to not ‘crash’ her Stiffness A material’s resistance to deformation biomechanics when she suddenly takes on the highly competitive unpredictable environment of the hockey Strain The amount of deformation that occurs pitch at the weekend. In most ball sports this is an early skill to be that does not retrace the force–length taught as a prerequisite to moving the feet quickly in tension curve traced when the force was response to the opposition’s play. It is the energy lost from the and habitual use of this stance, result in quadriceps tissue during this transaction dominance and a whole host of common sports inju- Elasticity The property of a material to return to its ries associated with such a posture – such as anterior original form or shape when a deforming cruciate ligament injury, meniscal tear, Achilles injury force is removed and plantar fasciitis (Wallden 2007). Hence, in condi- Viscosity The measure of shear force that must be tioning to survive his sport, such a sportsman must applied to a fluid to obtain a rate of use movement patterns and loading that help to deformation. In the the context within which the naturopathic triad is past, this potential difficulty has be circumnavigated embraced. If the objective of work in this field is to by describing ‘short and tight’ or ‘long and taut’ in the prevent injury and to realize potential as well as to same phrase, but ‘stiff’ also implies that there is resis- treat injury, then what is stated above still holds true. Hence the more sarco- Structural length versus functional tone meres in parallel, the more stiffness a tissue will have, One of the reasons that the popularity of evaluation whereas additional sarcomeres in series may result in of muscle imbalance may have dwindled in the little or no change to tissue stiffness. Study of the microstructure of skeletal muscle tells The nomenclature for muscle imbalance has been us that the sarcolemma, t-tubule and sarcoplasmic discussed by Sahrmann (2002) and the use of the word reticulum provide a direct connection from the sarco- ‘tight’ has been suggested to, perhaps rightly, be too mere to the endomysium, epimysium and perimy- nondescript and open to misinterpretation. In cases of traumatic scarring, ‘stiff’ denotes the mechanical property of the tissue or of long-term aberrant posture, tissues held in a (see Table 9. In such instances, contract–relax method- under long-term mechanical stress (Barnes 1997). Since being that have been held in a shortened position across held in an inner range or an outer range creates adap- extended periods of time – also involving their associ- tive stress on the musculoskeletal system, we can ated fascial nets – will respond better to low load expect an increased tone. Indeed, commonly the prolonged tensile forces, such as those deployed in patient perceives the greatest tone in the muscle being myofascial release techniques (Schleip 2003a) and held in a lengthened position – in its outer range. Since electron concept of muscle imbalance as being clinically un- microscopy has demonstrated that fascia has smooth useful. With a little closer attention, muscle imbalance muscle cells embedded within it (Barnes 1997), we can physiology can be understood to have a profound see that, once again, the primitive vegetative nervous influence on the human frame, its performance and system intricately links the musculoskeletal system its failure. Static versus dynamic dysfunction Thixotropic changes (where a tissue transforms from It is critical when assessing a patient to do so in a way a more gel-like state to a more soluble state) have been that is representative of how that individual uses his Box 9. On palpation, by stretching the quadriceps, the iliopsoas and working the hamstrings in particular felt very tight. A standing the hamstrings in their inner range using functional assessment revealed an anterior pelvic tilt of 11° exercise patterns. The Example 2 player had experienced a number of hamstring strains in Perhaps the most classic example of altered tone being his career and recently an ankle inversion injury. He was confused with altered length is the pain experienced by constantly feeling the need to stretch his hamstrings. Without assessing pelvic tilt, or lumbar lordosis Many manual therapy students spend a great deal of inclinometry, we would have no idea where to start time massaging each other’s rhomboids, stretching the advising the patient. He felt that his hamstrings were rhomboids and practicing other techniques on the ‘tight’ and on palpation they felt tight; they also rhomboids. Measuring his importance of assessing the patient rather than only hamstrings goniometrically, they appeared ‘short’, but in listening to the patient’s feelings as to his or her needs. Any deviation of structural length, whether long (left, dark gray column), or short (right, mid-gray column), results in increased tone. Since it is load (either micro or macro) that is the describes functional exercise as encompassing all of primary cause of injury, it is imperative to observe the following characteristics: how the body reacts under load – if we are both to treat and to prevent future injury in our clients. Maintenance of center of gravity over base of syndrome (lumbar flexion pattern) in their standing support: examination but when under load or when sprinting, • Dynamic they exceed their stabilization threshold and their • Static spine switches into a lower crossed syndrome (lumbar 3. The neutral spine philosophy is a concept that, essen- Some of these factors will be described below, but for tially, is based on good motor learning physiology, further reading see Chek (2000a). Most therapists will assess the client in out of a chair or other familiar movement patterns. However, consideration of motor will always move towards its position of strength Chapter 9 • Rehabilitation and Re-education (Movement) Approaches 347 (Chek 2001b). It is not based on the idea that the spine The healthy spine has 6° of freedom (flexion- should always remain in neutral, simply that in neu- extension in three planes and translation in three trality should be where the spine should be at its planes). Once again, This concept is supported by research from Richard- the point of the matter is that if the spine is not able son et al (1999) demonstrating that the transversus to maintain itself in an optimal alignment, its owner abdominis activates most effectively with the lumbo- simply will not ever reach their full performance pelvic region in ‘neutral’. According to Schaefer (1987), the optimal anteropos- Kapandji (1974) described how the Delmas index terior angulation of the spine should be in the region calculates that if the spine has either too much or too of 30–35°. Other researchers, such as Neumann (2002), little curve, this will disrupt the optimal transfer of suggest slight variations on these figures – but, in the load. Of course disruption in this way will result in main, these are due to methodological differences or increased injury risk and decreased performance. In through the facets (and facet compartments) – the those with low back pain, 96% were found to have minor posterior pillars. However, Bogduk (1997) and Adams et al (2002) also describe of the asymptomatic group, 76% of them had a poste- weight-bearing through the spine and indicate that rior disc herniation. None of these individuals was in some early research suggested that the zygapophy- any pain or had any awareness of their dysfunction. Just because have suggested that the facet joints can bear up to something is normal (forward head posture or upper 40% of the applied load, while other research has crossed syndrome are also good examples) does not suggested that, in the lumbar spine at least, the facet mean it is functional. We know, clinically, that poste- surface orientation means that no weight can be rior disc bulge is most commonly associated with a borne through these structures (Bogduk 1997). Hence it is However, the L4–5 and L5–S1 facets – the levels most likely that approximately three-quarters of the group commonly injured – are orientated in a position to assessed by Boos et al (1995) had a flattened lumbar weight-bear. This is not functional, but is the norm amongst facet joints to participate in weight-bearing, an aber- sedentary populations. A clinical epidemiological studies demonstrate that individuals example of just such an aberration may be the lower with seated (Western seated posture) occupations crossed syndrome. The disc, for move well outside of its range of neutral, as soon as example, is extremely strong and can withstand the spine migrates to a position outside of neutral its massive compressive stresses (more than the verte- risk of injury increases (see below).

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See cheap viagra plus 400 mg erectile dysfunction in diabetes management, for example purchase viagra plus online pills erectile dysfunction patient.co.uk doctor, Ethel Shanas generic 400mg viagra plus with mastercard erectile dysfunction medications comparison, The Health of Older People (Cam­ bridge: Harvard University Press, 1962) and “Health o f Older Peo­ ple,” Statistical Bulletin, New York, Metropolitan Life Insurance Company, September 1971. Department of Health, Education, and W elfare, Social Se­ curity Administration, Office of Research and Statistics, Compendium of National Health Expenditures Data (W ashington, D. Moreover, the 2 trillion figure is relative to other expenditures and is the product of a simple linear projection. Department of Health, Education, and Welfare, Public Health Service, Health Resources Statistics, 1972-73 (Washington, D. Leighton, “Epidemiology and Men­ tal Health” in Mental Health Considerations in Public Health, Public Health Service Publication 1898 (Washington, D. Kasl, Cobb, and Brooks traced increases in serum uric acid and cholesterol levels associated with loss of employment. These data are reported by Dodi Schultz, “The High Blood Pressure Tim e Bomb,” Viva, April 1974. Birley, “Crises and Life Changes and the Onset of Schizophrenia,” Journal of Health and Social Behavior, 9 (September 1968), 203-214. Kasl and Sidney Cobb, “Effects of Parental Status Incongruence and Discrepancy on Physical and Mental Health of Adult Offspring," Journal of Personality and Social Psychology, 7, 2 (October 1967). Leonard, “Children, Stress and Hospitalizations: A Field Experiment,” Journal of Health and Social Behavior, 9 (1968), 278. Shimkin, “Man, Ecology and Health,” Archives of Environmental Health, 20 (January 1970); and A. Looney, “Getting W hat We Pay For,” at the T hird Annual Meeting of the Comprehensive Health Planning Council of Maricopa County, Phoenix, Arizona, November 19, 1971. Unfortunately, escaping the carnage through cycling instead of driv­ ing is unpromising; in 1965 more than 700 persons died in accidents while cycling. See “Reports of the Division of Vital Statistics,” Na­ tional Center for Health Statistics, 1967. Department of Health, Education, and W elfare, National Institute of Alcohol Abuse and Alcoholism Report (Washington, D. These figures are understated—they include only reported addiction, a num ber far less than the num ber of addicted users. News and Chapter 4 253 World Report, October 9, 1972, 92; and National Clearinghouse for Smoking and Health, Director of On-Going Research in Smoking and Health, Report (W ashington, D. See A rthur Freese, “Traum a: The Neglected Epidemic,” Saturday Review, May 13, 1972, 58-62. The Ambulance Scandal: A Hazard to Life and Health,” Medical World News, 11 (December 4, 1970), 24. Brecher and the Editors of Consumer Reports, Licit and Illicit Drugs (Mount Vernon, N. Peter Koenig, “The Placebo Effect in Patent Medicine,” Psychology Today, April 1973, 60. Much of the Club’s methodology is based on the work of Jay Forrester, principally his book World Dynamics (Cam­ bridge: Wright-Alien Press, 1971). Garrett Hardin, “The Tragedy of the Commons,” Science, 162 (De­ cember 13, 1968), 1243-1248. Horn, “Smoking and Death Rates: Report on Forty-four Months of Follow-Up of 186,763 Men,” Journal of the American Medical Association, 166 (1958), 1294-1308. Stocks, “On the Relations Between Atmospheric Pollution in Urban and Rural Localities and Mortality from Cancer, Bronchitis, and Pneumonia, with Particular Reference to 3, 4-Benayprene, Beryl- liu, Molybdenum, Vanadium, and Arsenic,” British Journal of Cancer, 14 (1960), 397-418. Rene Laennec pointed out the relationship between fossil-fuel use in industrial production and the contaminants that caused emphysema in 1819. Surgeon General, The Health Consequences of Smoking, A Public Health Service Review, 1967 (Washington, D. The Seventh Annual Public Health Service Report to the Congress on the Consequences of Cigarette Smoking, reported in the New York Times, January 18, 1973. Calhoun, “Population Density and Social Pathology,” Scientific American, 206 (1962), 136. Andervont, “Influences of Environment on Mammary Cancer in Mice,” The Jour­ nal of the National Cancer Institute, 4 (1964), 579-581. For more mixed results, see also a survey of research on crowding, Psychology Today, April 1974. Anticaglia and Alexander Cohen, “Extra-Auditory Effects of Noise as a Health Hazard,” American Industrial Hygiene Association, 31 (1970), 277. See, for example, Harvey Schroeder, “Metals in the Air,” Environ­ ment, 13, 8 (October 1971), 18. Committee on Environmental Hazards of the American Academy of Pediatricians, “Acute and Chronic Childhood Lead Poisoning,” Pediatrics, 47, 5 (May 1971). See also Committee of Public Health, “Air Pollution and Health,” The New York Academy of Medicine Bulletin, 42, 7 (July 1966). Rennie, Mental Health in the Metropolis: Midtown Manhattan Study (New York: McGraw-Hill, 1962). The study did not investigate matched institutional and noninstitutional popula­ tions. The inference, rather, rests on a comparison of the num ber of persons under treatm ent for diagnosed mental illness and the nonin­ stitutionalized population studied. Langner, “Urban Life and Mental Health,” American Journal of Psychiatry, 113 (1957), 831; Leo Srole, Thomas S. Rennie, “Mental Disorders in a Metropolis,” Public Health Report, 72 (1957), 580; and E. Marches, “Mental Health Morbidity in a Suburban Community,” Journal of Clinical Psychology, 24, 1 (1968). Brian Cooper, John Fry, and Graham Kalton, “A Longitudinal Study of Psychiatric Morbidity in a General Practice Population,” British Journal of Preventive and Social Medicine, 23 (1969), 210. In other words, the size of the catch depends upon the size of the mesh of the net that is used; mental institutions Rnd the least, community services find more, and direct interviews find the most. Indeed, the over-enthusiastic psychiatric diagnostician can find evi­ dence of psychiatric ill-health in most hum an beings; such findings perhaps tell us more about the observer than about those observed” (P- 177). Some of the works to which I have reference are Imperial Animal by Tiger and Robin Fox (New York: Holt, Rinehart and Winston, 1971); The Naked Ape by Morris (New York: McGraw-Hill, 1967); African Genesis by Ardry (New York: Atheneum, 1967); and On Aggression by Lorenz (New York: Harcourt Brace Jovanovich, 1966). Konrad Lorenz, Civilized Man’s Eight Deadly Sins (New York: Harcourt Brace Jovanovich, 1974). Dohrenwend, Social Status and Psychological Disorder: A Causal Inquiry (New York: Wiley-Interscience, 1969). Skinner’s thesis is most cogently presented in Beyond Freedom and Dignity (New York: Knopf, 1971). Klerman, “Psychotropic Drugs as Therapeutic Agents,” Hastings Center Studies, 2, 1 (January 1974). Robert Coles, “The Case of Michael Wechsler,” New York Review of Books, May 18, 1972. See, for example, Thomas Szasz, The Manufacture of Madness (New York: H arper & Row, 1970), and R. The study is reported in Society, 9, 10 (September/October 1972), and was done by E.

The digital appearance of smaller matrix sizes can be improved by interpolation to large matrices for display purchase 400mg viagra plus overnight delivery impotence world association, although this will not improve resolution discount viagra plus 400 mg without prescription erectile dysfunction doctor washington dc. Whole body imaging Scan time varies depending on the count rate and count density required buy viagra plus with a mastercard erectile dysfunction kya hota hai. Because a whole body image covers about 200 cm, the matrix dimension along the length of the patient should be at least 512 pixels. Acquisition times greater than about 30 min are not practical for routine use in unsedated patients. Dynamic imaging The time per frame selected depends on the temporal resolution needed for the processing of the study and the organ function under investigation. Shorter times are preferred for quantitative functional studies, provided adequate statistics are obtained, in order to measure physiological changes. For purposes of qualitative imaging alone, somewhat longer times are generally used or multiple frames summed together in order to provide sufficient imaging statistics for each frame. For computer acquired images, the matrix size chosen for dynamic studies may be smaller than that required for static imaging provided that the resultant loss of resolution is acceptable for image interpretation. It is worth noting that sometimes a choice has to be made between word and byte mode acquisitions. If there is any doubt, word mode should be used to avoid pixel saturation that may occur in byte mode. Count rate loss should be ascertained by dead time measurements, about which a physicist can provide advice. Pinhole imaging Pinhole imaging provides the spatial resolution that most closely approaches the intrinsic limit of the camera at the expense of sensitivity. The distance between the collimator and the patient determines both the degree of magnification and the sensitivity (or count rate). Smaller pinhole apertures (2– 3 mm) provide better resolution but lower sensitivity. The acquisition matrix size will normally be 64 × 64 or 128 × 128 depending on the reconstructed resolution and field size. The manufacturer’s processing protocols should be consulted for compatibility with specific data acquisitions. The number of projections is likewise determined from similar sampling considerations. Consider a region, centred on the centre of rotation that includes the organ of interest. Then the arc at the edge of this region, defined by the detector position in two adjacent projections, should be approximately equal to the defined pixel size. In general, at least 60 (64) views are used for 360º acquisition or 30 (32) views for 180º acquisition. However, 120 (128) views should be used for high resolution studies such as those of the brain, irrespective of the matrix size used. Statistics play an important role in the reconstruction process and typically can prolong imaging times. Continuous rotation will provide the most efficient image gathering capability, especially if 120 (128) views are acquired. Introduction Nuclear cardiology is a superspecialty, in which nuclear physicians with training in cardiology, or cardiologists with nuclear medicine training, use nuclear imaging technology to investigate a variety of physiological and patho- logical aspects of the cardiovascular system. The major techniques used in nuclear cardiology can be categorized as: first pass angiocardiography, multi- gated blood pool imaging, myocardial perfusion imaging, and receptor and metabolic imaging. The data derived from these studies can be used for diagnosis, prognosis, treatment monitoring and assessment of viability in heart diseases, particularly in coronary artery disease. It involves the imaging of an intravenously injected radionuclide bolus during its initial transit through the central circulation. A time–activity curve is generated, and the temporal separation of the right and left ventricular phases allows evaluation of individual ventricular function. This is based on the assumption that thorough mixing of the tracer has occurred in the blood pool and that the detected count rate reflects the changes in ventricular volume during contraction and relaxation. Left and right ventricular function assessed at rest, or during stress with first pass imaging, gives a comprehensive evaluation of short duration changes that may affect the ventricles. This includes evaluation of global and regional wall motion, estimation of ejection fraction and other systolic and diastolic parameters. Such information has proved significant in the diagnosis, prognosis, decision making and management of certain clinical problems such as coronary artery disease and chronic obstructive lung disease, as well as congenital and valvular heart disease. Wall motion abnormalities, changes in end systolic volume and changes in diastolic filling rate are suggestive of ischaemia and the presence of coronary artery disease. The tracer bolus might not, however, mix completely with the right atrial blood prior to entering the right ventricle and may exit without mixing completely with apical blood, giving rise to potential sources of errors. The presence of a shunt is confirmed by simultaneous tracer appearance in the right and left ventricles. Quantitation of a left-to-right shunt is dependent on the quality of the bolus injected. A delayed or fragmented bolus may affect the shape of the pulmonary curve generated, which should be monoexponential, even in the absence of a shunt. Shunting separates the pulmonary activity curve into two components, which are proportional to the systemic and shunt flows, respectively, giving an index of the severity of the shunt. Studies showing prolonged tracer transit through the left side of the heart may 172 5. From the pulmonary and left ventricular time–activity curves, the degree of regurgitation may be calculated and quantified. Resting studies performed serially can be helpful in monitoring the severity of the valvular insufficiency and in deciding when valve replacement is necessary. Radiopharmaceuticals The ideal radionuclide as a first pass imaging agent must remain intravas- cular as it moves through the central circulation. It should also be safe for application in large doses in order to generate the necessary high count rates. Technetium-99m pertechnetate can be used when a single assessment of ventricular function is needed. Other technetium based compounds such as sestamibi and tetrofosmin are also suitable. First pass imaging can be performed upon injection of the tracer during peak exercise, thus combining information on regional and global ventricular function as well as myocardial perfusion in one setting. The half-life of 6 h and varying biological clearance times limit the number of acquisitions that can be done in a given period. In order to reduce the patient’s radiation exposure and allow for a greater number of studies to be performed, radionuclides with half-lives in terms of seconds or minutes would be ideal. Tantalum-178 produces suboptimal results when used with standard gamma cameras because of its low energy; more satisfactory results have been reported with a multiwire proportional gamma camera. Gold-195m is ideal for adult patients, and the calculated ejection fraction correlates well with that obtained using 99mTc agents. A bicycle ergometer is an additional requirement for first pass studies during exercise.

By N. Rufus. Maryville University of Saint Louis.