Radiography Imaging Techniques

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Questions and Answers

What is the cause of bending in a receptor during imaging?

Improper handling of the receptor (correct)

Receptor was warped

Improper technique used

Insufficient exposure time

Which appearance is associated with creasing in imaging?

Blurred images

Thin radiolucent line (correct)

Stretched images

Herringbone pattern

What correction can be made to avoid debris accumulation on a digital sensor?

Wipe the sensor between uses (correct)

Increase exposure time

Change imaging technique

Use a different receptor

What is the likely cause of phalangioma in an image?

Patient's finger positioned in front of the receptor Signup and view all the answers

What appears on the image when there is movement or motion unsharpness?

Blurry images Signup and view all the answers

What technique is likely affected by reversed or backward placement of the receptor?

Paralleling technique Signup and view all the answers

What is an effective correction method for preventing bending of a receptor?

Ensure proper placement before exposure Signup and view all the answers

Which condition is NOT a direct cause of motion unsharpness?

Use of a fast film type Signup and view all the answers

What is the proper position for the anterior edge of the bite-wing receptor in relation to the mandibular canine?

At the midline of the mandibular second premolar Signup and view all the answers

If a third molar region is not visible on an image, what could be the likely cause?

The bite-wing receptor was positioned too far anteriorly Signup and view all the answers

What is the correct action to take to avoid overlapping contacts when using the bite-wing technique?

Direct the central ray through the interproximal spaces Signup and view all the answers

What is the recommended vertical angulation to use with the bite-wing technique?

+10 degrees Signup and view all the answers

What appearance indicates a cone-cut when a beam alignment device is used?

A clear area on the image Signup and view all the answers

What is the main cause of a cone-cut when no beam alignment device is used?

PID not directed at the center of the receptor Signup and view all the answers

What is a potential cause for an unexposed receptor?

Failure to turn on the x-ray machine Signup and view all the answers

What common issue results from improperly aligned PID with a beam alignment device?

Clear area on the image (cone-cut) Signup and view all the answers

Which factor is NOT associated with distorted images using the bite-wing technique?

Incorrect horizontal angulation Signup and view all the answers

What appearance indicates that a film has been exposed to light?

The image appears black Signup and view all the answers

What correction should be made if a receptor is underexposed?

Check and adjust dual kilovoltage and milliamperage settings Signup and view all the answers

What causes an absence of apical structures in a receptor image?

The receptor was not positioned to cover the apical regions Signup and view all the answers

What is the appearance of an overexposed receptor?

The image appears dark or high in density Signup and view all the answers

What should be checked to correct a dropped receptor corner?

The edge of the receptor's alignment Signup and view all the answers

How can excessive exposure be prevented in x-ray imaging?

By reducing exposure time and adjusting machine settings Signup and view all the answers

What is the likely appearance of an underexposed receptor?

The image appears light or low in density Signup and view all the answers

What causes overlapped contacts in radiographic images?

The central ray was not directed through interproximal spaces Signup and view all the answers

Which technique is commonly associated with foreshortened images?

Bisecting technique when beam alignment is not used Signup and view all the answers

What is the appearance of an image with elongated teeth?

Long, distorted teeth Signup and view all the answers

What causes a cone-cut image when a beam alignment device is used?

PID not properly aligned with the periapical beam device Signup and view all the answers

In instances of unclear areas on radiographic images without a beam alignment device, what is the primary cause?

The PID was not directed at the center of the receptor Signup and view all the answers

What should be done to correct overlapping contacts during radiographic imaging?

Direct the x-ray beam through interproximal regions Signup and view all the answers

What appears on a radiograph if the bite-wing receptor is positioned too far posteriorly?

Distal surfaces of the canines are not visible Signup and view all the answers

What correction should be made to avoid foreshortened images?

Use adequate vertical angulation Signup and view all the answers

What occurs when x-ray photons collide with electrons in an atom?

Ionization is produced Signup and view all the answers

Which type of radiation is created when the primary beam interacts with matter?

Secondary radiation Signup and view all the answers

What is the nature of x-rays in relation to matter?

They can penetrate matter Signup and view all the answers

What does the latent period refer to in relation to radiation exposure?

The time lag before effects become evident Signup and view all the answers

How do tissues respond to exposure to x-rays over a lifetime?

They have cumulative effects which may not fully reverse Signup and view all the answers

What type of cells are affected by x-rays and can pass damage to future generations?

Reproductive cells Signup and view all the answers

What measurement unit is equivalent to Roentgen in SI units?

Coulombs per kilogram (C/kg) Signup and view all the answers

What is the maximum permissible dose of radiation for occupationally exposed individuals per week?

100 mrem Signup and view all the answers

Which duty does the dentist NOT have regarding radiographic practices?

Reduce the quality of images for less exposure Signup and view all the answers

What happens to x-ray equipment that is not properly maintained?

It poses a risk for radiation exposure Signup and view all the answers

Compared to x-rays, what happens with the shorter wavelengths of this radiation?

Higher energy levels are produced Signup and view all the answers

What is the role of scatter radiation in the context of x-ray exposure?

It occurs when x-rays are deflected from their original path Signup and view all the answers

Which of the following is TRUE about ionizing radiation?

It can cause damage to living tissues Signup and view all the answers

Which principle is essential for radiation protection in dental practices?

Utilize leading-edge shielding practices Signup and view all the answers

What is the primary cause of a double image appearing in digital radiography?

The receptor was exposed twice in the patient’s mouth Signup and view all the answers

Which statement is true about phosphor storage imaging?

A scanner is required to read the stored information Signup and view all the answers

How should an imaging plate be handled after exposure in phosphor storage imaging?

It must be placed in a light-proof barrier envelope Signup and view all the answers

Which is a key component of quality assurance in a dental office?

Monitoring x-ray equipment and supplies Signup and view all the answers

For what reason must the processing solutions in a dental radiography unit be replenished daily?

To ensure the solutions remain effective Signup and view all the answers

What is the role of the dental assistant in risk management related to radiography?

To avoid making negative comments about equipment Signup and view all the answers

What must patients be informed of for valid informed consent regarding radiographs?

The risks and benefits of imaging procedures Signup and view all the answers

What is a significant challenge with using digital imaging in dentistry?

The cost of implementing new technology Signup and view all the answers

Which aspect of digital radiography differentiates it from conventional x-ray imaging?

Instantaneous display of images on a computer Signup and view all the answers

What is required when using hard copies of digital images?

They must be printed on image quality paper Signup and view all the answers

Which of the following correctly describes the direct digital imaging method?

Utilizes a solid-state sensor for capturing images Signup and view all the answers

What must be done to ensure a properly functioning view box?

Ensure it emits uniform and subdued light Signup and view all the answers

How should a dental assistant handle requests for copies of dental radiographs?

Make an entry in the chart for record-keeping Signup and view all the answers

Study Notes

Unit 7: Radiation Characteristics and Radiation Protection

Ionization: Electrons remain stable in orbits around the nucleus until x-ray photons collide. Photons are bundles of pure energy with no weight or mass. Ions are atoms that have gained or lost an electron, becoming electrically unbalanced. X-rays have enough energy to push an electron out of its orbit, creating an ion in a process called ionization.

Review: Properties of X-Rays

X-rays are a form of energy that penetrates matter. Like visible light, radar, radio, and television waves, they are part of electromagnetic radiation. Electromagnetic radiation is made up of photons that travel at the speed of light in a straight line with a wave-like motion. The shorter the wavelength of an x-ray, the greater its energy.

Types of Radiation

Primary radiation: X-rays originating from the x-ray tube target (useful beam).
Secondary radiation: X-radiation created when the primary beam interacts with matter.
Scatter radiation: A form of secondary radiation resulting from the deflection of the x-ray beam from its path by interaction with matter.

Radiation Effects

All ionizing radiation is harmful, producing biological changes in living tissue. The amount of x-radiation used in dental radiography is small, but biological changes still occur. Dental assistants must understand how radiation's harmful effects occur and how to discuss risks with patients. The entire x-ray area is considered a radiation hazard area.

Biological Effects of Radiation

Exposure to radiation can cause changes in body chemicals, cells, tissues, and organs. These effects may not be evident for years after exposure. This time lag is the latent period.

Cumulative Effects

Exposure to radiation has a cumulative effect over a lifetime. When exposed to x-rays, some tissue damage occurs. Tissues can repair some damage, but do not return to their original state. The cumulative effect of radiation exposure is comparable to the cumulative effect of years of sun exposure.

Disorders of Critical Organs

Exposure to radiation can cause disorders in critical organs. This table lists some examples of these.
Lens of the eye: Cataracts
Bone marrow: Leukemia
Salivary gland: Cancer
Thyroid gland: Cancer
Skin: Cancer
Gonads: Genetic abnormalities

Genetic and Somatic Effects

X-rays affect both genetic and somatic cells. Genetic cells are reproductive cells (sperm and ova). Damage to them is passed on to future generations. All other body cells are somatic cells; x-rays can damage them, but the damage is not passed on to future generations.

Radiation Measurement

Radiation is measured similarly to time, distance, and weight. Two systems are used:
Traditional: Roentgen (R), radiation absorbed dose (rad), Roentgen equivalent man (rem)
SI: Coulombs per kilogram (C/kg), Gray (Gy), Sievert (Sv)

Maximum Permissible Dose

The maximum permissible dose (MPD) for occupationally exposed individuals is 5000 mrem (5.0 rem) per year, or 100 mrem per week. For non-occupationally exposed individuals, the current MPD is 500 mrem (5 mSv) per year.
Dental personnel should strive for an occupational dose of 0.

Responsibilities of the Dentists

Prescribe only necessary images.
Maintain radiographic equipment safely.
Ensure appropriate shielding for staff and patients.
Train personnel involved in image acquisition.
Use only necessary techniques for diagnostic images.
Adhere to regulatory requirements.
Obtain informed consent from patients and families.
Review patient records for prior imaging.

Protective Devices

Dental tubeheads must have components like aluminum filters and lead collimators.
Periodically check equipment using provincial or federal regulations.
Repair any faulty equipment immediately.

Patient Protection

Lead aprons and thyroid collars must be used on all patients for all exposures, regardless of age, sex or number of images.
Aprons should cover patients' necks to laps, to protect reproductive and blood-forming tissues from scatter radiation.

Fast-Speed Film

Film speed in film-based x-rays refers to the radiation needed to create an image. Film speed is primarily determined by the size of the silver bromide crystals. Larger crystals mean faster speed. Faster film requires less exposure to create a quality radiograph. Fast film is used for intraoral and extraoral radiography.

Image Receptor-Holding Devices

These devices keep patients' hands from x-ray exposure, keep the film stable and allow the operator to position the film/sensor and PID properly.

Proper Technique

Proper technique is essential for diagnostic quality images. Ensure minimal patient exposure. Retakes should be avoided because they increase radiation exposure to patients.

X-Rays During Pregnancy

Guidelines state that dental radiographic procedures don't need to be altered due to pregnancy.
Using a lead apron during procedures minimizes radiation to the pelvic region and is close to zero.
This protection minimizes detectable exposure to the embryo or fetus.

Radiation Monitoring

Film badges, pocket dosimeters (pen style), and thermoluminescent dosimeters (TLDs) are used to determine radiation exposure to personnel.

Equipment Monitoring

Dental x-ray machines must be monitored for radiation leakage. Faulty tubehead seals can cause leakage and need repair. Monitoring is done with calibration devices provided by the manufacturer or state health department.

Patient Questions

Provide explanations of procedures using clear, patient-friendly language.
Emphasize that the office takes necessary safety precautions.
Explain the use of lead aprons and thyroid collars.
Explain the use of high-speed film or sensor to reduce radiation exposure.

Informed consent: The operator must obtain and document informed consent from each patient before taking images.
Patient must receive an explanation in lay terms about procedure risks. A signed consent form provides documentation.
Confidentiality: Patient images are part of the patient record. Clinicians are obligated to ensure privacy in line with HIPAA and state/federal laws. Patients have the right to have copies of their records transmitted to other providers in keeping with professional courtesy.

Exposure and Technique Errors

There are several reasons why images can appear unexposed, overexposed, under-exposed, be absent of apical structures, have improperly placed receptors, be affected by overlapping contacts, be foreshortened or elongated, have cone-cut artifacts, or exhibit bending or creasing. Consult image examples for visualization of these image quality problems.

Unit 8: Quality Assurance, Legal Considerations, Digital Radiography

Digital Radiography

Digital images are used instead of traditional x-rays or films.
Digital images are electronic signals that are captured by sensors and displayed on a computer.
These are instant and can be e-mailed.
Hard copies can be printed on image quality paper.

Digital Radiography (Cont.)

Traditional x-ray machines are still needed to expose the images.
Strict infection control is needed when reusing sensors and phosphor storage plates.
FDA-cleared disposable barriers must be used with digital image sensors and phosphor plates.

Types of Digital Imaging Systems

Two basic methods exist:
Direct imaging
Indirect imaging

Direct Digital Imaging

A solid-state sensor (silicon chip with an embedded electronic circuit) is the image receptor.
The charge-coupled device (CCD) sensor is commonly used as a direct digital receptor.
Some CCDs are wireless, while others have direct connections to a computer, similar to telephones.

Indirect Digital Imaging

Phosphor storage plates (PSPs) are a common indirect digital imaging receptor.
A thin flexible plate, similar to film, is coated with phosphor crystals and used to store x-ray energy.
A scanner, using a laser beam, releases the energy to produce a digital image.

Phosphor Storage Imaging

After scanning, the plates are exposed to bright light to erase energy and are ready for reuse.
Infection control is crucial, using specially designed barrier envelopes for each plate.
The plates must not be autoclaved. Handling of the plates must be careful to avoid scratching.

Digitizing Film-Based Radiographs

Film-based radiographs can be digitized for computer viewing.
Digital scanners capture and digitize the light signal of the film as with other documents.
This process is akin to placing film on a duplicator lightbox for copy. This produces a less detailed image than direct digital imaging.

Digital Imaging Software Programs

Most digital imaging software offers image enhancement via contrast, brightness, zoom/sharpness, reversal, and pseudocolor adjustments.

Federal Regulations

Federal and provincial regulations govern dental x-ray equipment manufactured or sold in the U.S. after 1974. These include safety standards concerning filtration, accuracy of milliamperage-time and kilovoltage settings. Equipment is also subject to regional or provincial radiation health codes.

Provincial/Federal Requirements

The Healing Arts Radiation Protection Act necessitates proper training and certification for individuals performing dental radiographs.
Each province determines its policy for qualifying individuals to expose radiographs.
Specific approval from the province's HARP (Healing Arts Radiation Protection) approved educational institution might be required.

Risk Management

The dental practice utilizes risk management policies to reduce the likelihood of malpractice lawsuits.
Dental assistants play a crucial role in managing risk. They must be careful to avoid saying anything negative about the x-ray equipment or its operation. Statements made without careful consideration can put the office at risk.

It's the dentist's responsibility to explain the need for radiographs in a comprehensible way.
The dental assistant may provide support.
Patients should give informed consent, as required for dental procedures.

Patients need to receive information in plain language about the risks and benefits of radiographic procedures.
The specific person exposing the images, the number of images and their type, the consequences of not having images, and any alternative diagnostic methods should be explained.

Ownership of Dental Radiographs

Dental images belong to the dentist, not the patient or insurance provider. This applies even if they paid for the images.
Patients, however, can request copies of their images.

Quality Assurance

Quality assurance in dental offices is a method of ensuring high-quality diagnostic images. Specific quality control steps are needed involving equipment, supplies, image processing, and administrative processes. These include keeping records of maintenance and operations.

Types of Quality Control Tests

Regular testing of x-ray equipment (output, focal spot, tubehead stability, timer accuracy, milliamperage, and kilovoltage).
Film and PSP testing including examining film in boxes, unprocessed film quality, process results, and safelighting in the x-ray workroom.

X-Ray Machine Quality Control Steps

Routine testing of x-ray machine output, focal spot size, tubehead stability, timer accuracy, milliamperage, and kilovoltage.

Dental X-Ray Film: Traditional Film Plates

Film quality is checked initially and during processing. This checks for proper storage, handling, and processing.

View Boxes

View boxes should be routinely inspected for dirt and discoloration, and any damaged parts (bulbs) should be replaced.

Darkroom Lighting

Regular darkroom checks (e.g., every six months) should be done to detect any light leaks.

Processing Solutions

Processing solutions must be replenished daily and changed regularly to maintain quality. Testing the developer and fixer solutions can be used in place of calendar-based checks. Daily checks of the solution are important.

Stepwedge Radiograph

A stepwedge is a device with layered aluminum steps used to expose different densities of radiation on film. This is a quality control test that produces varying densities.

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Description

Test your knowledge on radiography imaging concepts and techniques. This quiz covers topics such as receptor bending, motion unsharpness, and sensor maintenance. Perfect for students studying dental or medical imaging.