DANB RHS Radiation Health and Safety - Set 3 - Part 1

Correct Answer: review the medical and dental history

Reviewing and updating the medical and dental history, including medications and allergies, comes first so the clinician can spot contraindications and explain the procedure before any setup begins. Option a is incorrect because setting exposure factors is a later technical step taken at the machine once the patient is prepared; doing it first would skip the history that guides the whole appointment. Option b is incorrect because mounting belongs at the end, after images are captured and arranged for viewing; it has no place as the opening step of preparing a patient for exposure. Option d is incorrect because positioning the tubehead happens just before exposure, after the patient is seated and aligned, so it cannot be the first action before any history or seating occurs.

Correct Answer: informed consent

Radiation carries a small cumulative risk, so the patient must give informed consent after the procedure and its benefits are explained, which is required before exposing any images. Option b is incorrect because a retainer is an orthodontic appliance and is actually removed before exposure to avoid artifacts; it is not something a patient provides to authorize imaging. Option c is incorrect because a copy fee may apply only later if the patient requests duplicates of finished records; it has nothing to do with the consent needed before exposure. Option d is incorrect because the office supplies the lead apron and thyroid collar as part of protection; the patient does not bring shielding, and shielding is not the authorization being asked about.

Correct Answer: eyeglasses, jewelry, and removable appliances

Dense objects in or near the beam cast artifacts, so eyeglasses, earrings, necklaces, oral piercings, and removable dentures or retainers are taken out before the receptor and beam are set. Option a is incorrect because socks and shoes lie far outside the beam path of a head and neck exposure, so removing them accomplishes nothing for image quality or artifact prevention. Option b is incorrect because limiting removal to a wristwatch misses the real culprits; a watch is well away from the field, while metal on the face, ears, and mouth is what actually interferes. Option c is incorrect because removing nothing leaves metal jewelry and appliances in the beam, which produce bright artifacts and, on a panoramic, a displaced ghost that can hide diagnostic detail.

Correct Answer: ghost image on the opposite side

On a panoramic, a dense object like an earring is projected across to the opposite side, higher, larger, and blurred, creating a ghost image that can obscure real anatomy. Option a is incorrect because a metal object does not sharpen anything; it adds a misleading artifact, and leaving it in place degrades the image rather than improving definition of the condyle. Option c is incorrect because a lighter image reflects underexposure, an exposure-factor issue; a dense earring blocks the beam and creates a bright artifact, which is unrelated to overall image lightness. Option d is incorrect because exposure time on a panoramic is governed by the unit's program, not by jewelry; an earring cannot shorten the exposure, it only superimposes an unwanted ghost.

Correct Answer: reduce cross-contamination

Washing the hands before gloving lowers the microbial load and helps stop pathogens from moving between operator and patient, so hand hygiene is a core step in reducing cross-contamination. Option a is incorrect because hand hygiene protects against infection and does nothing to the timing of the exposure, which is controlled by the machine settings rather than by clean hands. Option b is incorrect because contrast is determined by kilovoltage and technique, not by handwashing; clean hands safeguard health but have no effect on the tonal range of the image. Option d is incorrect because the PID length is a fixed property of the equipment chosen for the exposure; hand hygiene is an infection-control measure and cannot change the cone's length.

Correct Answer: thyroid collar

Intraoral imaging pairs the lead apron with a thyroid collar to shield the highly radiosensitive thyroid gland from scatter radiation, so the collar is standard for every intraoral exposure. Option b is incorrect because a longer PID reduces dose by changing beam geometry, but it is equipment, not patient shielding; it does not cover the thyroid the way the collar does. Option c is incorrect because a bite block stabilizes the receptor during exposure; it positions the film rather than shielding tissue, so it is not the protective item paired with the apron. Option d is incorrect because a rubber dam isolates a tooth during restorative or endodontic treatment and plays no role in radiographic shielding of the patient against scatter.

Correct Answer: left off to avoid an artifact

The rotating panoramic beam passes through the neck region, so a thyroid collar would block it and leave a radiopaque cone-shaped artifact; the collar is omitted and the apron placed low. Option a is incorrect because doubling the collar would only enlarge the very artifact that must be avoided, blocking more of the rotating beam and obscuring more of the diagnostic image. Option b is incorrect because placing the collar over the chin would put dense material directly in the path of the mandible and teeth, again casting a blocking artifact across the image. Option c is incorrect because wrapping the collar around the head adds shielding where the beam travels, producing exactly the radiopaque interference that omitting the collar is meant to prevent.

Correct Answer: parallel to the floor

Standard intraoral positioning places the occlusal plane parallel to the floor and the midsagittal plane perpendicular to it, which keeps the arch level and the projection geometry predictable and consistent. Option a is incorrect because perpendicular to the floor is how the midsagittal plane is oriented, not the occlusal plane; swapping the two would tilt the bite plane and distort the projection. Option b is incorrect because a forty-five-degree tilt corresponds to no standard reference orientation for intraoral work and would throw off the alignment of the beam, receptor, and teeth. Option d is incorrect because facing the ceiling describes an extreme upward tip of the head, not the level occlusal plane the technique calls for, and it would misalign the exposure.

Correct Answer: the chin tipped too high

Raising the chin too high tips the occlusal plane upward, producing a reverse downward smile line and pushing the condyles out of the image, a classic panoramic positioning error. Option a is incorrect because tipping the chin too low produces the opposite error, an exaggerated upward smile line, so a downward reverse curve cannot come from a chin that is too low. Option c is incorrect because failing to raise the tongue lets a dark air shadow obscure the maxillary apices; it is a separate fault that does not bend the smile line downward. Option d is incorrect because a slumped spine can cast a radiopaque shadow over the anterior region, but it does not create the downward smile line and missing condyles described here.

Correct Answer: Frankfort plane

Panoramic positioning sets the Frankfort plane parallel to the floor while the midsagittal plane stays perpendicular to it, which centers the head correctly so the teeth fall within the focal trough. Option a is incorrect because the midsagittal plane is held perpendicular to the floor to keep the head from tilting side to side, so it is not the plane oriented parallel to the floor. Option b is incorrect because the occlusal plane is the reference for intraoral positioning, not the panoramic landmark; panoramic alignment instead relies on the Frankfort plane, not on the midsagittal one. Option c is incorrect because the sagittal suture is an anatomic joint of the skull, not a positioning reference plane, so it is not used to level the head for a panoramic exposure.

Correct Answer: control panel

The machine is built from the tubehead that produces the beam, the extension arm that positions it, and the control panel where exposure settings are selected and the exposure is initiated. Option b is incorrect because a lead apron is patient shielding draped over the body, not a component of the x-ray machine, so it is not one of the unit's three main parts. Option c is incorrect because a receptor holder stabilizes the sensor or plate inside the mouth; it is an accessory used with the machine rather than a structural part of the unit itself. Option d is incorrect because a view box illuminates film for reading and sits apart from the exposure equipment, so it is not counted among the parts of the x-ray machine.

Correct Answer: outside the room or behind a barrier

The operator activates the exposure from outside the room or behind a protective barrier, using distance and shielding to limit occupational exposure to scatter radiation during the shot. Option a is incorrect because standing right beside the tubehead places the operator in the area of greatest scatter, the opposite of the safe position the exposure switch is meant to allow. Option b is incorrect because remaining inside the operatory beside the patient keeps the operator in the scatter field, which protection principles of distance and shielding are designed to avoid. Option d is incorrect because the switch is not located under the chair; that position offers no shielding and would still expose the operator to scatter close to the source.

Correct Answer: remove weak, low-energy x-rays

Aluminum filtration absorbs the weak, low-energy x-rays that would only add to patient dose without contributing to the image, leaving a more useful, higher-energy beam to reach the patient. Option a is incorrect because enlarging the beam is not filtration's job; beam size is restricted by the collimator, while the filter changes the quality of the beam by stripping out soft rays. Option b is incorrect because holding the receptor is the role of a bite block or holder; the filter is a metal disc inside the tubehead and never contacts or supports the receptor. Option c is incorrect because the filter alters which photon energies pass, not the gray scale; contrast is governed by kilovoltage, so filtration is not a tool for softening contrast.

Correct Answer: a long rectangular PID

A long rectangular PID limits the beam close to the receptor's shape and increases the source distance, so it irradiates the least tissue and lowers patient dose more than the alternatives. Option a is incorrect because a short pointed PID widens the beam and increases scatter and tissue irradiated, raising dose rather than lowering it, so it is the opposite of the best choice. Option c is incorrect because a heavier apron shields covered areas but does not reduce the dose delivered to the field being imaged; beam-limiting geometry is what cuts that exposure. Option d is incorrect because a faster computer speeds image display and processing, a workflow benefit, but it has no effect on how much radiation the beam delivers to the patient.

Correct Answer: a cone cut

If the arm is loose, the tubehead drifts off center during the exposure, so the beam no longer fully covers the receptor and leaves an unexposed clear area called a cone cut. Option b is incorrect because contrast is a function of kilovoltage and technique; a drifting tubehead misaligns the beam and clips coverage rather than changing the tonal range of the image. Option c is incorrect because scanning speed belongs to PSP plate readout and is unrelated to the tubehead; a loose arm affects beam aim, not how fast a plate is processed afterward. Option d is incorrect because a thyroid artifact comes from leaving the collar in a rotating panoramic beam, a different cause entirely from a drifting tubehead clipping an intraoral exposure.

Correct Answer: bitewings

In the familiar color scheme, blue holders are for anterior periapicals, yellow for posterior periapicals, and red for bitewings, so red identifies the bitewing assembly the operator reaches for. Option a is incorrect because anterior periapicals use the blue holder components in this color system, not the red ones, so red would direct the operator to the wrong assembly for that view. Option b is incorrect because occlusal images have the patient bite a large receptor and do not rely on the color-coded periapical and bitewing holders, so red does not designate an occlusal setup. Option c is incorrect because panoramic imaging uses no intraoral holder at all, since the receptor rotates outside the mouth, so the red bitewing components have no role in a panoramic exposure.

Correct Answer: paralleling

The XCP instrument holds the receptor parallel to the tooth and guides the beam through an aiming ring, so it is the device built to support the paralleling technique. Option a is incorrect because the bisecting technique uses different holders such as a BAI or grip device, since its geometry aims the beam at an imaginary bisector rather than along parallel planes. Option b is incorrect because occlusal images need no aiming ring or paralleling holder; the patient simply bites the receptor, so an XCP instrument is not the tool for that projection. Option d is incorrect because panoramic exposures place no receptor in the mouth and rely on the rotating unit, so an intraoral paralleling instrument like the XCP has no application there.

Correct Answer: centered in the aiming ring

Proper XCP assembly aligns the receptor so it appears centered within the aiming ring, which lines the beam up through the receptor and prevents cone cuts and angulation errors. Option b is incorrect because reversing the receptor in the bite block would face the wrong side toward the beam and produce a faint herringbone image, the opposite of correct assembly. Option c is incorrect because taping the receptor to the tubehead defeats the holder's purpose and misplaces the receptor entirely; the XCP positions it in the mouth, not on the tube. Option d is incorrect because having the patient hand-hold the receptor abandons the holder altogether and exposes the patient's fingers, which correct XCP use is specifically designed to avoid.

Correct Answer: a caregiver wearing protection

When holding is unavoidable, a parent or caregiver, wearing a lead apron and thyroid collar, may hold the receptor; staff are never used for this repeated occupational exposure. Option a is incorrect because the operator must never hold a receptor in a patient's mouth, because repeating that across many patients would expose staff to radiation again and again. Option b is incorrect because another assistant is still a staff member, so using one merely shifts the same prohibited repeated occupational exposure onto a different employee who is exposed daily. Option c is incorrect because the dentist is likewise an occupationally exposed staff member and should not hold receptors; the task falls to a one-time caregiver who is properly shielded.

Correct Answer: the receptor in the mouth

Holding a receptor in the patient's mouth places the operator's hand in the primary beam and repeats that exposure daily, so this is never done; a holder or shielded caregiver is used instead. Option a is incorrect because the control panel is where the operator stands to set factors and initiate the exposure from safety; touching it is normal and carries no extra radiation risk. Option c is incorrect because the lead apron is draped on the patient before exposure and is not held during the shot; handling it beforehand is routine and poses no beam exposure. Option d is incorrect because the patient's chart is reviewed before imaging and kept away from the field; it is not held in the beam, so it is not the hazard being warned against.