Free PRC RadTech Exam Flashcards

Bremsstrahlung comes from electrons slowing in the target's electric field and produces a continuous spectrum. Characteristic photons come from vacancies filled by electrons from higher shells, producing discrete energies. Characteristic radiation is not restricted to K-shell transitions. Tungsten has atomic number 74 and a K-shell binding energy of about 69.5 keV, so incident electrons must exceed that energy to create a K-shell vacancy. A tube operated below that threshold can still produce bremsstrahlung and lower-shell characteristic radiation.

Photoelectric absorption removes the incident photon and ejects a bound electron; it strongly favors higher atomic numbers and lower photon energies away from absorption edges. Compton scattering transfers some photon energy to an electron and redirects the remaining photon. Scatter reaching the detector reduces useful contrast and is an important source of staff exposure. The familiar atomic-number and energy power laws are approximations with specified quantities and energy ranges, not universal formulas for every tissue or absorption edge.

40 µGy: multiply 160 by (1/2)². The inverse-square model assumes the same source output, negligible intervening attenuation, and distances sufficiently large compared with source dimensions. Doubling distance spreads the same radiation over four times the area. A patient is an extended scatter source, so this simple result is not an exact staff-dose prediction close to the patient. Distances must be measured from the source, and both distances must use the same units.

The cathode side has greater beam intensity because photons emerging toward the anode side travel farther through target material and undergo greater self-absorption. Where the examination geometry permits, place the thicker portion of the anatomy toward the cathode. The effect varies with anode angle, field size and geometry; it is not a fixed percentage correction. Check the equipment orientation and the prescribed projection rather than assuming that a named body end always belongs under the cathode.

Half-value layer is the thickness of a specified absorber that reduces a narrow beam's air kerma to half its initial value under the stated measurement conditions. Removing preferentially low-energy photons generally increases mean beam energy and HVL while reducing output. HVL is a beam-quality measure, not simply the physical thickness of the tube's filter. Additional filtration may require an exposure adjustment. Equipment acceptance limits depend on modality, operating voltage and the applicable regulator; PNRI radioactive-material rules are not the Philippine X-ray equipment standard.

A waveform that stays nearer its peak voltage accelerates electrons at higher energies for more of the exposure. Compared with a single-phase waveform, this generally increases output and beam penetration at the same indicated kVp and mAs. High-frequency equipment produces a relatively stable waveform, but its exact ripple and heat-rating factors are manufacturer dependent. Do not assume every high-frequency generator has less than 1% ripple or that changing generator type exactly doubles output. Use the equipment technique and tube-rating data.

Cells with substantial future division and limited differentiation are often radiosensitive because reproductive damage becomes evident when they divide. However, mature lymphocytes can undergo radiation-induced apoptosis despite not fitting a simple rapid-division rule. Sensitivity also depends on cell type, oxygenation, dose and endpoint. In a simple exponential survival model, D₀ is the dose reducing survival by a factor of e, approximately to 37%; it is not a universal threshold below which cells cannot be injured.

Tissue reactions, such as sufficiently severe skin injury or lens changes, involve loss or dysfunction of enough cells; their occurrence has dose thresholds that depend on the endpoint and exposure conditions, and severity generally increases with dose. Stochastic effects concern the probability of cancer or heritable effects, rather than a predictable increase in severity. Radiation protection commonly uses a linear no-threshold model for stochastic risk at low doses. That protective model does not prove that any particular small exposure will cause cancer.

Record the examination, exposure settings, irradiated region and likely gestational age, then obtain a patient-specific fetal dose assessment from an appropriately qualified specialist when indicated. Risk depends on dose and developmental stage, not on a single universal 'all-or-nothing' number. IAEA guidance states that fetal doses below 100 mGy do not justify pregnancy termination on radiation risk alone. This is a counseling principle, not a guarantee of zero risk or a reason to omit necessary imaging.

For practices within PNRI's scope, both effective dose and lens equivalent dose are limited to 20 mSv per year averaged over five consecutive years, with 50 mSv in any single year. The adult skin and extremity equivalent-dose limit is 500 mSv in a year. Thus 150 mSv is not the current adult PNRI lens limit. CPR Part 3 expressly excludes X-rays and other electrically generated radiation under DOH-FDA responsibility; patient medical exposure is also not governed by these worker dose limits.

Increase kVp to 92 and reduce mAs to 10: 80 × 1.15 = 92 and 20 ÷ 2 = 10. This is an approximate technique-conversion rule under otherwise comparable conditions, not an exact physical equivalence. Beam penetration, subject contrast and patient dose can change. A processed digital image can retain similar brightness over a wide exposure range, so brightness alone cannot confirm correct exposure. Use the validated technique chart, exposure indicator and diagnostic image quality.

32.4 mAs, using 10 × (180/100)² = 10 × 3.24. This direct-square compensation assumes the same kVp, attenuation, detector conditions and other relevant factors. It compensates for distance-related intensity loss at the receptor; it does not prove unchanged patient dose or geometric magnification. Keep units consistent: 100 cm is approximately 39.4 inches, while 180 cm is approximately 70.9 inches, so neither is exactly the commonly rounded 40- or 72-inch setting.

25 mAs: 5 × 5. The Bucky factor is the exposure or mAs multiplication needed with the specified grid under the relevant conditions to maintain receptor exposure. It is not determined solely by grid ratio, because primary transmission, scatter conditions, field size and beam quality also matter. A 12:1 ratio therefore does not by itself prove a factor of 5. In clinical work, use validated grid-conversion data and check alignment before increasing exposure.

The grid strips are angled to match rays diverging from a focal spot within a specified distance range. At an incorrect distance, progressively more primary photons are intercepted toward the image edges, causing peripheral cutoff. An upside-down focused grid also causes marked peripheral loss. Lateral decentering by itself can produce relatively uniform primary loss, rather than necessarily one-sided cutoff. Evaluate orientation, centering, level and SID together; simply increasing mAs can add dose without correcting the geometry.

Source-to-object distance is 100 − 10 = 90 cm. Magnification is SID/SOD = 100/90 ≈ 1.11. Detector-plane geometric unsharpness is focal spot × OID/SOD = 0.6 × 10/90 ≈ 0.067 mm. These are simplified projection-geometry calculations with a single object plane and consistent distance units. They do not include motion or detector blur. Reducing object-to-detector distance and using an appropriate smaller focal spot generally improve geometric sharpness.

Development converts exposed silver-halide crystals associated with the latent image into metallic silver, making the image visible. Fixation removes remaining unexposed silver halide and stabilizes the image against subsequent light exposure. Washing removes residual chemicals, and drying prepares the film for handling. Developer temperature, replenishment and processing time affect optical density and contrast. A weak or contaminated developer cannot be corrected reliably by increasing patient exposure; identify the processing fault and restore the validated process.

An indirect detector first converts X-rays into light in a scintillator, such as cesium iodide, and then converts the light to electrical charge. A direct detector uses a photoconductor, commonly amorphous selenium, to convert absorbed X-ray energy into charge without a light-conversion stage. These conversion paths affect spatial resolution and efficiency, but neither label alone guarantees superior performance for every task. Pixel pitch, detector design, dose, noise and processing all contribute to the final image.

The pitch is 0.100 mm, so the Nyquist frequency is 1/(2 × 0.100) = 5 cycles/mm, commonly expressed as 5 line pairs/mm. This is a sampling limit, not proof that the complete system resolves 5 lp/mm with useful contrast. Focal-spot blur, detector response, motion and noise may reduce actual performance. Structure above the sampling limit can alias into misleading lower-frequency patterns unless it is adequately suppressed before sampling.

DI = 10 log₁₀(EI/EIₜ), so EI/EIₜ = 10^(3/10) ≈ 2.00: the exposure index is about twice its target. DI = −3 corresponds to about half the target. EI relates to detector exposure under its calibration and image-analysis conditions, not directly to the patient's absorbed dose. Check collimation, segmentation, anatomy and image quality. A DI outside the preferred range is a reason to investigate technique, not an automatic instruction to repeat an otherwise diagnostic image.

Expose a control film with a standardized sensitometer and measure specified optical-density points with a densitometer. Compare base-plus-fog, speed and contrast indicators with established baseline and action limits. Because the control exposure is standardized, a shift can reveal processing drift before patient images are affected. Investigate temperature, chemistry and replenishment rather than compensating by changing every patient's technique. Keep film batch and test conditions consistent so that comparisons are meaningful.

PA positioning brings the heart closer to the detector, reducing its magnification; the usual long source-to-image distance further limits magnification. An upright projection also helps demonstrate air-fluid relationships and allows a more reproducible inspiratory examination. Assess rotation, inspiration, coverage and scapular position together. A fixed rib count is an aid rather than an absolute adequacy rule for every patient. If the patient cannot stand or rotate safely, use the clinically indicated adapted projection and document the position.

Gas rises while fluid settles, so a horizontal beam can demonstrate their vertical separation. A left lateral decubitus abdominal projection can show free gas adjacent to the liver, separated from the normal gastric air on the left. Position and timing must follow the patient's condition and the requested examination; do not delay urgent assessment or force an unstable patient to remain in a position merely to satisfy a memorized waiting time. Record the position and obtain the appropriate clinical review.

The conventional Towne beam is directed 30° caudally to the orbitomeatal line, or 37° caudally to the infraorbitomeatal line, preserving the intended relationship despite the approximately 7° difference between reference lines. Evaluate the resulting anatomy and rotation, rather than the tube angle alone. The dorsum sellae and posterior clinoids should project within the foramen magnum. These are routine positioning relationships; suspected cervical injury requires a safe adapted examination, not forced neck flexion.

The conventional parietoacanthial Waters position places the OML at about 37° to the detector with the central ray perpendicular to the detector, projecting the petrous ridges below the maxillary sinuses. For an examination intended to demonstrate fluid levels, use an appropriate upright or adapted horizontal-beam geometry. A submentovertex view is a different basal projection and is not inherently an erect horizontal-beam view. Do not extend an injured or uncleared neck simply to reproduce a textbook position.

Preserve spinal precautions and use the clinically indicated trauma imaging pathway. Do not rotate, flex or hyperextend an uncleared neck to obtain a routine oblique, swimmer's or Fuchs view. If radiography is requested, adapt the tube and detector where possible and ensure adequate coverage; inability to obtain a diagnostic view must be escalated, not solved by unsafe movement. CT may be the appropriate examination in many trauma scenarios. A projection mnemonic never overrides assessment, immobilization or the authorized imaging decision.

The AP oblique Grashey projection aligns the scapular plane with the detector to open the glenohumeral joint space. Routine body rotation is commonly about 35–45°, adjusted to the patient's anatomy, while the beam is directed to the joint. A scapular-Y projection instead profiles the scapula and helps assess the humeral head's relationship to the glenoid. In suspected fracture or dislocation, avoid forced arm movement and use a safe prescribed adaptation rather than pursuing a fixed angle at any cost.

The conventional Gaynor-Hart view uses wrist extension to project the carpal canal tangentially. That movement can be inappropriate with acute pain, suspected fracture or instability. Confirm the indication, assess the patient's ability to move and follow the radiologist's approved alternative; never force hyperextension to obtain the named view. The aim is diagnostic demonstration of the relevant carpal anatomy with safe geometry. An eponym describes a projection, not permission to manipulate an injured joint.

With the affected side down in the iliac oblique, the posterior column and anterior acetabular wall are emphasized. With the affected side up in the obturator oblique, the anterior column and posterior wall are emphasized. The views are complementary and require correct side labeling. In an acutely injured patient, substantial rotation may be unsafe or impractical; follow the trauma team's imaging decision and use a supported adaptation or alternative imaging rather than automatically rolling the patient through both positions.

A routine mortise projection rotates the entire lower limb internally by approximately 15–20° to bring the intermalleolar line nearer parallel to the detector and demonstrate the ankle mortise with less tibiofibular overlap. The required angle varies with anatomy, so evaluate the joint spaces rather than accepting the nominal angle alone. Do not twist an unstable ankle or perform an unsupervised stress view. If pain or injury prevents positioning, obtain the prescribed safe alternative and document the limitation.

A suspected leak usually prompts initial use of an appropriate water-soluble iodinated agent rather than barium, because escaped barium can cause serious complications. Agent selection also depends on aspiration risk and the clinical question; hyperosmolar iodinated agents can be hazardous if aspirated. A negative initial examination does not automatically exclude a small leak, and a radiologist may select an additional study or carefully considered barium examination. Fistula or prior surgery alone is not a universal ban on barium.

No. Republic Act 7431 regulates professional practice and protects the relevant professional titles. The degree is an educational qualification for the radiologic-technologist examination; it is not itself the professional registration. An applicant must meet the applicable eligibility requirements and complete the PRC registration process after qualifying. Distinguish the Radiologic Technologist and X-Ray Technologist routes. Do not infer a detailed modality-by-modality scope prohibition solely from the difference between a degree and a diploma.

The Board has five members: three registered radiologic technologists, including the chair, one radiologist and one medical physicist. Statutory qualifications include being at least 30 years old and the applicable professional practice experience. The law also restricts relevant faculty positions and pecuniary interests in schools offering the courses. This professional mix is different from a board made entirely of radiologic technologists. Read the statutory conflict rules precisely rather than adding an unsupported blanket ban covering every review-center relationship.

RA 7431 section 22 requires a weighted average of at least 75% with no subject rating below 60%. Candidates with an average of at least 75% but a subject below 60% repeat the deficient subjects, which then require at least 75%. The law refers to failure to qualify at the third examination, while PRC's current checklist describes three removal examinations; have PRC confirm the applicable attempt history. These are official ratings, not a guaranteed 375-of-500 raw-score conversion.

Confirm an appropriate lawful basis and follow the institution's privacy and authorization process. Remove unnecessary identifiers from both the displayed image and associated metadata, and use only an approved teaching channel. A name hidden on the screen does not establish that the DICOM file is anonymous. The professional duty to protect confidentiality continues outside the examination room. Consent for clinical imaging does not automatically authorize public posting, and an educational purpose does not by itself make all disclosures lawful.

The coronal, or frontal, plane divides the body into anterior and posterior portions. A sagittal plane divides left from right, while a transverse plane divides superior from inferior portions. These terms describe anatomy independently of how the patient happens to lie. Before interpreting an image orientation or positioning instruction, identify the patient's anatomical axes and the labeled side. Confusing a plane with a projection direction can produce a technically adequate image of the wrong relationship.

Pause and reconcile the discrepancy before exposure. Use the approved patient identifiers, confirm the requested anatomy and side, and contact the referring or supervising clinician through the established process when clarification is needed. Do not let a room number or an assumption based on a visible injury replace identification. Document the resolved instruction and communicate it to the team. Correct identification and a clear clinical question are part of patient care, not administrative steps to be skipped when the department is busy.

Bradycardia with hypotension can suggest a vasovagal event, while bronchospasm, airway swelling or widespread urticaria can support an allergic-like reaction, but presentations overlap and may evolve. Stop the injection, summon the trained response team, assess airway, breathing and circulation, and use the institution's emergency protocol. Do not delay care because one expected sign is absent. Medication, dose and route require the authorized trained response; an isolated flashcard is not a substitute for the reaction-management chart.

Assess the patient's mobility, pain, consciousness and any spinal or weight-bearing precautions; secure lines, drains and oxygen connections, and obtain enough trained assistance and suitable transfer equipment. Align the surfaces, secure the trolley and explain the coordinated movement to the patient and team. Stop if the transfer would violate precautions or cannot be performed safely. Good body mechanics do not make an unsupported manual lift safe; the method must fit both the patient's needs and the equipment available.

They are added to Standard Precautions when the suspected or confirmed infection requires them. For example, pulmonary tuberculosis calls for airborne precautions, while some infections need more than one additional category. Coordinate essential transport, patient source control and room preparation with infection-control staff; clean and disinfect equipment using the applicable procedure afterward. A portable examination can reduce movement when clinically appropriate, but it does not eliminate the need for PPE, hand hygiene or environmental controls.

Use 100–120 compressions per minute, a depth of at least 5 cm while avoiding depths greater than 6 cm, full recoil and minimal interruptions. Without an advanced airway, conventional CPR uses 30 compressions to 2 breaths. Activate the emergency response and obtain an AED promptly. These targets apply within the current adult BLS algorithm: assess responsiveness and breathing, and a healthcare professional checks for a definite pulse for no more than 10 seconds. Start CPR when indicated rather than prolonging the assessment.

Pitch is table travel per rotation divided by the total nominal beam width. With fixed tube current, rotation time and other relevant settings, increasing pitch spreads the exposure over more length and generally reduces dose per scanned length. For example, changing pitch from 1 to 1.5 gives an idealized inverse factor of 1/1.5 ≈ 0.67. Automatic exposure control or effective-mAs compensation can change this relationship. Therefore, pitch alone does not establish the patient's dose or diagnostic image quality.

CTDIvol characterizes scanner output using a standardized dosimetry phantom and acquisition conditions. DLP multiplies CTDIvol by scan length: 10 mGy over 30 cm gives 300 mGy·cm. Neither quantity directly measures an individual patient's organ dose; patient size, anatomy and protocol matter. CT numbers are a different quantity: Hounsfield units describe attenuation relative to water, with water near 0 HU and air near −1000 HU under the conventional scale. Do not interchange HU, mGy and mGy·cm.

Using frequency = 42.58 MHz/T × magnetic-field strength gives approximately 63.87 MHz at 1.5 T and 127.74 MHz at 3 T. This uses the proton gyromagnetic ratio expressed in cycles per second per tesla; an angular-frequency form uses a different factor containing 2π. Resonance frequency is not an X-ray photon energy or the MRI gradient strength. Tissue contrast additionally depends on the pulse sequence and relaxation behavior, so field strength alone does not determine whether fluid will appear bright.

No. Current ACR guidance distinguishes gadolinium agent groups and the clinical need. In CKD stages 4–5, group I agents are contraindicated; if contrast-enhanced MRI is needed, a group II agent should be used. Group II agents are also preferred when AKI is known or suspected. Renal risk must be assessed with the supervising clinician, and the lowest diagnostic dose is used. Do not translate a high-risk agent restriction into a blanket refusal of all gadolinium or rely on one eGFR value to exclude AKI.

The system commonly assumes 1540 m/s for soft-tissue imaging and calculates depth from the echo's round-trip travel time. If actual propagation speed differs, the displayed depth can be displaced. This is an imaging assumption, not a claim that all tissues transmit sound at the same speed. Frequency also involves a penetration–resolution trade-off: higher frequencies generally attenuate more but can improve resolution. Use the appropriate transducer, acoustic output and exposure time for the diagnostic task under ALARA.

They assess different contaminants: Mo-99 breakthrough is radionuclidic contamination, while aluminum breakthrough is chemical contamination from the generator system. For the TECHNELITE product label, Mo-99 must not exceed 0.15 µCi per mCi of Tc-99m at administration, and aluminum must not exceed 10 µg/mL; the user checks both before administration. Those are product-label criteria with stated units and timing, not interchangeable activity and mass limits. Tc-99m is useful for its approximately 140 keV photon, but its decay is not literally free of conversion or Auger electrons.

After a positron loses kinetic energy, annihilation with an electron commonly produces two photons of approximately 511 keV traveling in nearly opposite directions. Coincidence detection identifies a line of response; it does not require the mechanical collimator used in a conventional gamma camera. Photon directions are not exactly 180° in every event, which contributes to resolution limitations. Patient preparation, such as fasting for an FDG study, is tracer- and protocol-specific rather than a universal requirement for every nuclear-medicine examination.

Dividing a prescribed treatment into fractions allows sublethal-damage repair and changes the biological response through repair, redistribution, reoxygenation and repopulation. These effects do not all favor treatment success: tumor repopulation can oppose control, particularly during prolonged overall treatment. Fraction size, total dose and schedule must follow the individualized plan. A technologist must not alter fractions or add bolus independently; bolus changes dose distribution and is used only as specified and verified within the treatment workflow.

For IV iodinated contrast, a patient without AKI and with eGFR at least 30 mL/min/1.73 m² does not need metformin stopped solely for the contrast examination under ACR guidance. With AKI, eGFR below 30, or arterial catheter studies that might embolize the renal arteries, withhold it at or before the procedure, continue withholding for 48 hours and reassess renal function before restarting. Drug labeling or institutional policy can be more restrictive. The concern is metformin accumulation if kidney function deteriorates, not a direct contrast–metformin reaction.

IAEA guidance uses 5 Gy reference air kerma as a trigger for patient follow-up for possible tissue reactions. It is not a direct measurement of peak skin dose and does not by itself prove a skin injury or define a sentinel event. Peak skin dose, when available, is the preferred indicator; the corresponding suggested follow-up trigger is 3 Gy. Record the dose metrics, account for relevant repeated procedures and follow the institution's monitoring and counseling process. Fluoroscopy time alone is a poorer indicator.