PRELIMINARY STEPS IN RADIOGRAPHY

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PRELIMINARY STEPS IN RADIOGRAPHY



OUTLINE




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Ethics in Radiologic Technology


Ethics is the term applied to a health professional’s moral responsibility and the science of appropriate conduct toward others. The work of the medical professional requires strict rules of conduct. The physician, who is responsible for the welfare of the patient, depends on the absolute honesty and integrity of all health care professionals to carry out orders and report mistakes.


The American Society of Radiologic Technologists (ASRT) developed the current code of ethics.1 The Canadian Association of Medical Radiation Technologists (CAMRT) has adopted a similar code of ethics.2 All radiographers should familiarize themselves with these codes.



AMERICAN SOCIETY OF RADIOLOGIC TECHNOLOGISTS CODE OF ETHICS




1. The radiologic technologist conducts himself or herself in a professional manner, responds to patient needs, and supports colleagues and associates in providing quality patient care.


2. The radiologic technologist acts to advance the principal objective of the profession to provide services to humanity with full respect for the dignity of humankind.


3. The radiologic technologist delivers patient care and service unrestricted by concerns of personal attributes or the nature of the disease or illness, and without discrimination, regardless of gender, race, creed, religion, or socioeconomic status.


4. The radiologic technologist practices technology founded on theoretic knowledge and concepts, uses equipment and accessories consistent with the purpose for which they have been designed, and employs procedures and techniques appropriately.


5. The radiologic technologist assesses situations; exercises care, discretion, and judgment; assumes responsibility for professional decisions; and acts in the best interest of the patient.


6. The radiologic technologist acts as an agent through observation and communication to obtain pertinent information for the physician to aid in the diagnosis and treatment management of the patient. He or she recognizes that interpretation and diagnosis are outside the scope of practice for the profession.


7. The radiologic technologist uses equipment and accessories; employs techniques and procedures; performs services in accordance with an accepted standard of practice; and demonstrates expertise in minimizing radiation exposure to the patient, self, and other members of the health care team.


8. The radiologic technologist practices ethical conduct appropriate to the profession and protects the patient’s right to quality radiologic technology care.


9. The radiologic technologist respects confidence entrusted in the course of professional practice, respects the patient’s right to privacy, and reveals confidential information only as required by law or to protect the welfare of the individual or the community.


10. The radiologic technologist continually strives to improve knowledge and skills by participating in educational and professional activities, sharing knowledge with colleagues, and investigating new and innovative aspects of professional practice.



CANADIAN ASSOCIATION OF MEDICAL RADIATION TECHNOLOGISTS CODE OF ETHICS


The CAMRT recognizes its obligation to identify and promote professional standards of conduct and performance. The execution of such standards is the personal responsibility of each member.


The code of ethics, adopted in June 1991, requires all members to do the following:



• Provide service with dignity and respect to all people regardless of race, national or ethnic origin, color, gender, religion, age, type of illness, and mental or physical challenges.


• Encourage the trust and confidence of the public through high standards of professional competence, conduct, and appearance.


• Conduct all technical procedures with due regard to current radiation safety standards.


• Practice only those procedures for which the necessary qualifications are held unless such procedures have been properly delegated by an appropriate medical authority and for which the technologist has received adequate training to an acceptable level of competence.


• Practice only those disciplines of medical radiation technology for which he or she has been certified by the CAMRT and is currently competent.


• Be mindful that patients must seek diagnostic information from their treating physician. In those instances where a discreet comment to the appropriate authority may assist diagnosis or treatment, the technologist may feel morally obliged to provide one.


• Preserve and protect the confidentiality of any information, either medical or personal, acquired through professional contact with the patient. An exception may be appropriate when the disclosure of such information is necessary to the treatment of the patient or the safety of other patients and health care providers or is a legal requirement.


• Cooperate with other health care providers.


• Advance the art and science of medical radiation technology through ongoing professional development.


• Recognize that the participation and support of our association is a professional responsibility.



Image Receptor


In radiography, the image receptor (IR) is the device that receives the energy of the x-ray beam and forms the image of the body part. In diagnostic radiology, the IR is one of the following five devices:



1. Cassette with film: A device that contains special intensifying screens that glow when struck by x-rays and imprints the x-ray image on film. The use of a darkroom, where the film is developed in a processor, is required. Afterward the radiographic film image is ready for viewing on an illuminator (Fig. 1-1, A).



2. Image plate (IP): A device, used for computed radiography (CR), similar to a conventional intensifying screen. The IP is housed in a specially designed cassette that contains special phosphorus to store the x-ray image. The IP is a component of the new “digital” imaging systems. The cassette is inserted into a reader device, which scans the IP with a laser. The radiographic image is converted to digital format and is viewed on a computer monitor or printed on film (Fig. 1-1, B).


3. Solid-state detectors: A flat panel thin-film transistor (TFT) detector or a charge-coupled device (CCD) used for direct digital radiography (DR). This type of digital imaging system is called “cassetteless” because it does not use a cassette or an IP. The flat panel detector or CCD built into the x-ray table or other device captures the x-ray image and converts it directly into digital format. The image is viewed on a computer monitor or printed on film (Fig. 1-1, C). This is the fastest processing system with images available in 6 seconds or less. The DR flat panel detector is a component of the new “digital” imaging systems.


4. Portable digital radiography: A portable, lightweight DR system that can be used for lateral and axial imaging of limbs and for trauma and bedside applications. Its 14 × 17 inches (35 × 43 cm) size is large enough for chest and abdomen images. The unit can be tethered to the computer via Ethernet, or the newest systems allow wireless transmission (Fig. 1-1, D).


5. Fluoroscopic screen: X-rays strike a fluoroscopic screen, where the image is formed and is transmitted to a television monitor via a camera. This is a “real-time” device in which the body part is viewed live on a television (Fig. 1-1, E).



Radiograph


Each step in performing a radiographic procedure must be completed accurately to ensure that the maximal amount of information is recorded on the image. The information that results from performing the radiographic examination generally shows the presence or absence of abnormality or trauma. This information assists in the diagnosis and treatment of the patient. Accuracy and attention to detail are essential in each radiologic examination.


The radiographer must be thoroughly familiar with the radiographic attenuation patterns cast by normal anatomy structures. To develop the ability to analyze radiographs properly and to correct or prevent errors in performing the examination, the radiographer should study radiographs from the following standpoints:



1. Superimposition: The relationship of the anatomic superimposition to size, shape, position, and angulation must be reviewed.


2. Adjacent structures: Each anatomic structure must be compared with adjacent structures and reviewed to ensure that the structure is present and properly shown.


3. Optical density (OD): OD is known as degree of blackening when associated with radiographic film and as brightness when describing appearance on a digital display monitor. The OD must be within a “diagnostic range” to display all desired anatomic structures. Images with ODs outside the diagnostic range (too light or too dark) are primarily associated with screen-film radiography (Fig. 1-2), although they are possible with digital imaging. The primary controlling factor for screen-film OD is milliampere-second (mAs). For digital imaging, the OD of displayed images is primarily controlled by automatic rescaling, so mAs selection affects patient radiation dose and image noise.



4. Contrast: The contrast, or the difference in density between any two areas on a radiograph, must be sufficient to allow radiographic distinction of adjacent structures with different tissue densities. A wide range of contrast levels is produced among the various radiographic examinations performed (Fig. 1-3). A low-contrast image displays many density levels, and a high-contrast image displays few density levels. The primary controlling factor of radiographic contrast is kilovoltage peak (kVp).



5. Recorded detail: The recorded detail, or the ability to visualize small structures, must be sufficient to show clearly the desired anatomic part (Fig. 1-4). Recorded detail is primarily controlled by the following:




6. Magnification: The magnification of the body part must be evaluated, taking into account the controlling factors of object–to–image receptor distance (OID), or how far the body part is from the IR, and source–to–image receptor distance (SID), or how far the x-ray tube is from the IR. All radiographs yield some degree of magnification because all body parts are threedimensional (Fig. 1-5).



7. Shape distortion: The shape distortion of the body part must be analyzed, and the following primary controlling factors must be studied:



An example of shape distortion is when a bone is projected longer or shorter than it actually is. Distortion is the misrepresentation of the size or shape of any anatomic structure (Fig. 1-6).



A strong knowledge of anatomy and the ability to analyze radiographs correctly are paramount—especially to radiographers who work without a radiologist in constant attendance. In this situation, the patient’s physician must be able to depend on the radiographer to perform the technical phase of examinations without assistance.




ANATOMIC POSITION


Radiographs are usually oriented on the display device so that the person looking at the image sees the body part placed in the anatomic position. The anatomic position refers to the patient standing erect with the face and eyes directed forward, arms extended by the sides with the palms of the hands facing forward, heels together, and toes pointing anteriorly (Fig. 1-7). When the radiograph is displayed in this manner, the patient’s left side is on the viewer’s right side and vice versa (Fig. 1-8). Medical professionals always describe the body, a body part, or a body movement as though it were in the anatomic position.





Posteroanterior and anteroposterior radiographs


Fig. 1-9, A, illustrates the anterior (front) aspect of the patient’s chest placed closest to the IR for a posteroanterior (PA) projection. Fig. 1-9, B, illustrates the posterior (back) aspect of the patient’s chest placed closest to the IR for an anteroposterior (AP) projection. Regardless of whether the anterior or posterior body surface is closest to the IR, the radiograph is usually placed in the anatomic position (Fig. 1-10). (Positioning terminology is fully described in Chapter 3.)




Exceptions to these guidelines include the hands, fingers, wrists, feet, and toes. Hand, finger, and wrist radiographs are routinely displayed with the digits (fingers) pointed to the ceiling. Foot and toe radiographs are also placed on the illuminator with the toes pointing to the ceiling. Hand, finger, wrist, toe, and foot radiographs are viewed from the perspective of the x-ray tube, or exactly as the anatomy was projected onto the IR (Figs. 1-11 and 1-12). This perspective means that the individual looking at the radiograph is in the same position as the x-ray tube.





Lateral radiographs


Lateral radiographs are obtained with the patient’s right or left side placed against the IR. The patient is generally placed on the illuminator in the same orientation as though the viewer were looking at the patient from the perspective of the x-ray tube at the side where the x-rays first enter the patient—exactly like radiographs of the hands, wrists, feet, and toes. Another way to describe this is to display the radiograph so that the side of the patient closest to the IR during the procedure is also the side in the image closest to the illuminator. A patient positioned for a left lateral chest radiograph is depicted in Fig. 1-13. The resulting left lateral chest radiograph is placed on the illuminator as shown in Fig. 1-14. A right lateral chest position and its accompanying radiograph would be positioned and displayed the opposite of that shown in Figs. 1-13 and 1-14.






Other radiographs


Many other less commonly performed radiographic projections are described throughout this atlas. The most common method of displaying the radiograph that is used in the radiology department and most clinical practice areas is generally either in the anatomic position or from the perspective of the x-ray tube; however, there are exceptions. Some physicians prefer to view all radiographs from the perspective of the x-ray tube rather than in the anatomic position. A neurosurgeon operates on the posterior aspect of the body and does not display spine radiographs in the anatomic position or from the perspective of the x-ray tube. The radiographs are displayed with the patient’s right side on the surgeon’s right side as though looking at the posterior aspect of the patient. What the surgeon sees on the radiograph is exactly what is seen in the open body part during surgery.



Clinical History


The radiographer is responsible for performing radiographic examinations according to the standard department procedure except when contraindicated by the patient’s condition. The radiologist is a physician who is board certified to read, or interpret, x-ray examinations. As the demand for the radiologist’s time increases, less time is available to devote to the technical aspects of radiology. This situation makes the radiologist more dependent on the radiographer to perform the technical aspects of patient care. The additional responsibility makes it necessary for the radiographer to know the following:



Although the radiographer is not responsible for explaining the cause, diagnosis, or treatment of the disease, the radiographer’s professional responsibility is to produce an image that clearly shows the abnormality.


When the physician does not see the patient, the radiographer is responsible for obtaining the necessary clinical history and observing any apparent abnormality that might affect the radiographic result (Fig. 1-17). Examples include noting jaundice or swelling, body surface masses possibly casting a density that could be mistaken for internal changes, tattoos that contain ferrous pigment, surface scars that may be visible radiographically, and some decorative or ornamental clothing. The physician should give specific instructions about what information is necessary if the radiographer assumes this responsibility.



The requisition received by the radiographer should clearly identify the exact region to be radiographed and the suspected or existing diagnosis. The patient must be positioned and the exposure factors selected according to the region involved and the radiographic characteristics of the existent abnormality. Radiographers must understand the rationale behind the examination; otherwise, radiographs of diagnostic value cannot be produced. Having the information in advance prevents delay, inconvenience, and, more importantly, unnecessary radiation exposure to the patient.


With many institutions updating to electronic records, the radiographer may be using the computer system to enter information about the patient. In many of these information systems, the full patient’ history may be accessed. The radiographer needs to observe rules of confidentiality.



Advanced Clinical Practice


In response to increased demands on the radiologist’s time, a level of advanced clinical practice has developed for the radiographer. This advanced clinical role allows the radiographer to act as a “radiologist extender,” similar to the physician assistant for a primary care physician. These radiographers take a leading role in patient care activities, perform selected radiologic procedures under the radiologist’s supervision, and may be responsible for making initial image observations that are forwarded to the supervising radiologist for incorporation into the final report. The titles of radiologist assistant (RA) and radiology practitioner assistant (RPA) are currently used to designate radiographers who provide these advanced clinical services in the diagnostic imaging department. Requirements for practice include certification as a radiographer by the ARRT, pertinent additional education, and clinical experience under the supervision of a radiologist preceptor. RAs and RPAs also write advanced-level certification examinations.





Care of the Radiographic Examining Room


The radiographic examining room should be as scrupulously clean as any other room used for medical purposes. The mechanical parts of the x-ray machine, such as the tableside, supporting structure, and collimator, should be wiped with a clean, damp (not soaked) cloth daily. The metal parts of the machine should be periodically cleaned with a disinfectant. The overhead system, x-ray tube, and other parts that conduct electricity should be cleaned with alcohol or a clean, dry cloth. Water is never used to clean electrical parts.


The tabletop should be cleaned after each examination. Cones, collimators, compression devices, gonad shields, and other accessories should be cleaned daily and after any contact with a patient. Adhesive tape residue left on cassettes and cassette stands should be removed, and the cassette should be disinfected. Cassettes should be protected from patients who are bleeding, and disposable protective covers should be manipulated so that they do not come in contact with ulcers or other discharging lesions. Use of stained or damaged cassettes is inexcusable and does not represent a professional atmosphere.


The radiographic room should be prepared for the examination before the patient arrives. The room should look clean and organized—not disarranged from the previous examination (Fig. 1-18). Fresh linens should be put on the table and pillow, and accessories needed during the examination should be placed nearby. Performing these preexamination steps requires only a few minutes but creates a positive, lasting impression on the patient; not performing these steps beforehand leaves a negative impression.




Standard Precautions


Radiographers are engaged in caring for sick patients and should be thoroughly familiar with standard precautions. They should know the way to handle patients who are on isolation status without contaminating their hands, clothing, or apparatus, and radiographers must know the method of disinfecting these items when they become contaminated. Standard precautions are designed to reduce the risk of transmission of unrecognized sources of blood-borne and other pathogens in health care institutions. Standard precautions apply to:



Handwashing is the easiest and most convenient method of preventing the spread of microorganisms (Fig. 1-19, A). Radiographers should wash their hands before and after working with each patient. Hands must always be washed, without exception, in the following specific situations:




As one of the first steps in aseptic technique, radiographers’ hands should be kept smooth and free from roughness or chapping by the frequent use of soothing lotions. All abrasions should be protected by bandages to prevent the entrance of bacteria.


For the protection of the health of radiographers’ and patients’, the laws of asepsis and prophylaxis must be obeyed. Radiographers should practice scrupulous cleanliness when handling all patients, whether or not the patients are known to have an infectious disease. If a radiographer is to examine the patient’s head, face, or teeth, the patient should ideally see the radiographer perform handwashing. If this is not possible, the radiographer should perform handwashing and then enter the room drying the hands with a fresh towel. If the patient’s face is to come in contact with the IR front or table, the patient should see the radiographer clean the device with a disinfectant or cover it with a clean drape.


A sufficient supply of gowns and disposable gloves should be kept in the radiographic room to be used to care for infectious patients. After examining infectious patients, radiographers must wash their hands in warm, running water and soapsuds and rinse and dry them thoroughly. If the sink is not equipped with a knee control for the water supply, the radiographer opens the valve of the faucet with a paper towel. After proper handwashing, the radiographer closes the valve of the faucet with a paper towel.


Before bringing a patient from an isolation unit to the radiology department, the transporter should drape the stretcher or wheelchair with a clean sheet to prevent contamination of anything the patient might touch. When the patient must be transferred to the radiographic table, the table should be draped with a sheet. The edges of the sheet may be folded back over the patient so that the radiographer can position the patient through the clean side of the sheet without becoming contaminated.


A folded sheet should be placed over the end of the stretcher or table to protect the IRs when a non-Bucky technique is used. The IR is placed between the clean fold of the sheet, and with the hands between the clean fold, the radiographer can position the patient through the sheet. If the radiographer must handle the patient directly, an assistant should position the tube and operate the equipment to prevent contamination. If a patient has any moisture or body fluids on the body surface that could come in contact with the IR, a non–moisture-penetrable material must be used to cover the IR.


When the examination is finished, the contaminated linen should be folded with the clean side out and returned to the patient’s room with the patient. There the linen receives the special attention given to linen used for isolation unit patients or is disposed of according to the established policy of the institution. All radiographic tables must be cleaned after patients have touched it with their bare skin and after patients with communicable diseases have been on the table (Fig. 1-19, B).



Disinfectants and Antiseptics


Chemical substances that kill pathogenic bacteria are classified as germicides and disinfectants (e.g., dilute bleach is sometimes used as a disinfectant). Disinfection is the process of killing only microorganisms that are pathogenic. The objection to the use of many chemical disinfectants is that to be effective, they must be used in solutions so strong that they damage the material being disinfected. Chemical substances that inhibit the growth of but without killing pathogenic microorganisms are called antiseptics. Alcohol, which is commonly used for medical or practical asepsis in medical facilities, has antiseptic but not disinfectant properties. Sterilization, which is usually performed by means of heat or chemicals, is the destruction of all microorganisms.



Centers for Disease Control and Prevention


For the protection of health care workers, the U.S. Centers for Disease Control and Prevention (CDC)1 has issued recommendations for handling blood and other body fluids. According to the CDC, all human blood and certain body fluids should be treated as if they contain pathogenic microorganisms (Box 1-1). These precautions should apply to all contacts involving patients. Health care workers should wear gloves whenever they come into contact with blood, mucous membranes, wounds, and any surface or body fluid containing blood. For any procedure in which blood or other body fluids may be sprayed or splashed, the radiographer should wear a mask, protective eyewear (e.g., eye shields, goggles), and a gown.



Health care workers must be cautious to prevent needle stick injuries. Needles should never be recapped, bent, broken, or clipped. Instead, they should be placed in a puncture-proof container and properly discarded (Fig. 1-20).




Operating Room


Chapter 29 of this atlas contains comprehensive information about the radiographer’s work in the operating room (OR). A radiographer who has not had extensive patient care education must exercise extreme caution to prevent contaminating sterile objects in the OR. The radiographer should perform handwashing and wear scrub clothing, a scrub cap, and a mask and should survey the particular setup in the OR before bringing in the x-ray equipment. By taking this precaution, the radiographer can ensure that sufficient space is available to do the work without the danger of contamination. If necessary, the radiographer should ask the circulating nurse to move any sterile items. Because of the danger of contamination of the sterile field, sterile supplies, and persons scrubbed for the procedure, the radiographer should never approach the operative side of the surgical table unless directed to do so.


After checking the room setup, the radiographer should thoroughly wipe the x-ray equipment with a damp (not soaked) cloth before taking it into the OR. The radiographer moves the mobile machine, or C-arm unit, to the free side of the operating table—the side opposite the surgeon, scrub nurse, and sterile layout (Fig. 1-21). The machine should be maneuvered into a general position that makes the final adjustments easy when the surgeon is ready to proceed with the examination.



The IR is placed in a sterile covering, depending on the type of examination to be performed. The surgeon or one of the assistants holds the sterile case open while the radiographer gently drops the IR into it, being careful not to touch the sterile case. The radiographer may give directions for positioning and securing the cassette for the exposure.


The radiographer should make the necessary arrangements with the OR supervisor when performing work that requires the use of a tunnel or other special equipment. When an IR is being prepared for the patient, any tunnel or grid should be placed on the table with the tray opening to the side of the table opposite the sterile field. With the cooperation of the surgeon and OR supervisor, a system can be developed for performing radiographic examinations accurately and quickly without moving the patient or endangering the sterile field (Fig. 1-22).




Minor Surgical Procedures in the Radiology Department


Procedures that require a rigid aseptic technique, such as cystography, intravenous urography, spinal punctures, angiography, and angiocardiography, are performed in the radiology department (Fig. 1-23). Although the physician needs the assistance of a nurse in certain procedures, the radiographer can make the necessary preparations and provide assistance in many procedures.



For procedures that do not require a nurse, the radiographer should know which surgical instruments and supplies are necessary and how to prepare and sterilize them. Radiographers may make arrangements with the surgical supervisor to acquire the education necessary to perform these procedures.





Motion and Its Control


Patient motion plays a large role in radiography (Fig. 1-24). Because motion is the result of muscle action, the radiographer needs to have some knowledge about the functions of various muscles. The radiographer should use this knowledge to eliminate or control motion for the exposure time necessary to complete a satisfactory examination. The three types of muscular tissue that affect motion are the following:





INVOLUNTARY MUSCLES


The visceral (organ) muscles are composed of smooth muscular tissue and are controlled partially by the autonomic nervous system and the muscles’ inherent characteristics of rhythmic contractility. By their rhythmic contraction and relaxation, these muscles perform the movement of the internal organs. The rhythmic action of the muscular tissue of the alimentary tract, called peristalsis, is normally more active in the stomach (about three or four waves per minute) and gradually diminishes along the intestine. The specialized cardiac muscular tissue functions by contracting the heart to pump blood into the arteries and expanding or relaxing to permit the heart to receive blood from the veins. The pulse rate of the heart varies with emotions, exercise, diet, size, age, and gender.


Involuntary motion is caused by the following:




Mar 4, 2016 | Posted by in GENERAL RADIOLOGY | Comments Off on PRELIMINARY STEPS IN RADIOGRAPHY
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