Physics, Applied Anatomy, and Procedures Practice Flashcards

Comprehensive review flashcards covering X-ray physics, Ultrasound, CT principles, Mammography, Nuclear Medicine, MRI sequences, Anatomy, and Radiation Protection.

How do X-rays differ from visible light in terms of wavelength and penetration?

X-rays have a very short wavelength and are able to penetrate many substances that are opaque to light.

How is a posteroanterior (PA) chest radiograph defined?

A radiograph where the x-ray beam passes through the back of the patient and exits through the front to reach the detector.

Which form of radiography uses a phosphor imaging plate to capture a latent image?

Computed radiography

What modality enables real-time radiographic visualization of moving anatomic structures?

Fluoroscopy

What is the standardized x-ray source-to-image distance (SID) for an upright chest radiography?

$$183\,cm$$

What are the two general effects of using lower kV settings in radiography?

Increase the dose to the patient and increase the contrast.

What is the most widely used technology for reducing scattered radiation emanating from the patient?

Scatter grid

What is considered the gold standard in scatter reduction methods?

Bucky grid

What does transmission imaging refer to?

Imaging where the energy source is outside the body on one side, passes through the body, and is detected on the other side.

What is projection imaging?

An imaging case where each point on the image corresponds to information along a straightline trajectory through the patient.

In which modality is contrast produced by differences in tissue composition, local absorption coefficient, density, and effective atomic number?

Mammography

Which modality has the highest spatial resolution in radiology?

Screen film Mammography

Which type of photon interaction with matter is utilized specifically in nuclear medicine as mentioned in the text?

Pair production

Which radiological quantity does NOT use the Sievert (Sv) as its system international (SI) unit?

Absorbed dose

In ultrasound, what is the appearance of a totally homogeneous medium with no reflecting interfaces?

Anechoic

Which ultrasound technique measures longitudinal tissue displacement before and after compression?

Strain Elastography

Which artifacts may floor-fill structures with false debris and reduce lateral resolution?

Side lobe

What artifact arises when signals reflect repeatedly between highly reflective interfaces near the transducer?

Reverberation

Which ultrasound approach can provide reduction of phase aberration effects?

Tissue Harmonic

Which ultrasound technique is much less angle-dependent and ignores flow direction or velocity?

Power Doppler

Which ultrasound echo display mode is used to evaluate moving organs like myocardium and valve leaflets?

M-mode

What is the major determinant of the response of contrast bubbles to ultrasound?

Mechanical index

What type of artifact results from ultrasound energy emitted far off-axis by multi-element arrays?

Grating lobes

What is the functional component of the ultrasound transducer?

Piezoelectric element

Which artifact appears as a rapidly changing mixture of colors distal to a strong reflector like calculus?

Twinkling

In CT, what is the term for data collected at a specific angle of interrogation of the object?

Projection or View

What kind of x-ray interaction is more likely to occur in soft tissues during CT?

Compton

Which CT component reduces incident x-ray beam intensity in the periphery of the x-ray field?

Bow tie filter

Define spiral scan CT scanning.

When the table moves at a constant speed while the gantry rotates around the patient.

Which cardiac CT gating technique records electrocardiogram data in synchrony with continuous imaging?

Retrospective gating

What is focal spot blooming?

The increase in size of the x-ray focus.

What does a hard x-ray spectrum refer to?

A spectrum with high average x-ray energies.

Which artifact occurs when there are too few projection images to reconstruct a high frequency object?

View aliasing

Which CT generation uses a rotate-translate motion with a narrow fan beam?

2nd

What is the effect of a CT pitch greater than $1.0$ on patient dose?

It results in a lower radiation dose to the patient.

Which anode target material is preferred for digital mammography detectors due to higher efficiency and melting point?

Tungsten

What material is used for the tube port window of a mammography machine?

Beryllium

What is a significant limitation of magnification in mammography?

Increased dose factor

What is the SI unit of radioactivity?

Becquerel (Bq)

Which nucleus is identical to an alpha particle?

Helium nucleus

What is cyclotron production in nuclear medicine?

The production of radionuclides by bombarding stable nuclei with high-energy charged particles.

Which radionuclide is used in more than $70\%$ of all imaging studies?

Technetium-99m

In nuclear medicine, what is chemotaxis?

The movement of a cell, such as a leukocyte, in response to a chemical stimulus.

What is the most common nuclear imaging device, developed by Hal O. Anger?

Scintillation camera

What is the most common positron-emitting radionuclide used in PET?

Flourine-18

What is the precessional frequency of $1H$ at $1.5\,T$ according to the Larmor equation?

$$63.87\,MHz$$

What is transverse magnetization ($M_{xy}$)?

The component of the magnetic moment perpendicular to $B_0$ in the x-y plane.

Which MRI pulse sequence uses a very short TI ($140$ to $180\,ms$) to reduce fat signals?

Short Tau Inversion Recovery (STIR)

What is the basic formula for MRI Acquisition time?

$$\text{Acquisition time} = TR \times \text{Phase encoding steps} \times \text{Number of excitations}$$

Which MRI artifact occurs at tissue-air interfaces due to rapid dephasing ($T2^*$)?

Susceptibility artifacts

What is the wrap-around artifact in MRI?

Mismapping of anatomy outside the FOV that is displaced to the opposite side of the image.

In MRS, which metabolite peak is a sign of hypoxia and potential high-grade malignancy?

Lipid peak

In the Couinaud classification, what is Segment VII of the liver?

The superior posterior segment of the right hepatic lobe.

Which inverted pyramid-shaped space lies posterior to the maxillary sinus?

Pterygopalatine fossa

Which heart chamber forms the anterior border adjacent to the sternum on a lateral projection?

Right ventricle

In the prostate gland, where does most cancer occur?

Peripheral zone

Which principle of radiation protection does ALARA follow?

Principle of Optimization

What is the maximum dose to the fetus of a declared pregnant radiation worker over the gestational period?

$5\,mSv$ ($0.5\,rem$)

Which radiation dosimeter provides a permanent record?

Film badge

What is the typical lead equivalent thickness of a protective apron?

$0.25$ to $0.5\,mm$

What is the maximum annual effective dose limit for non-occupational (public) persons?

$$1\,mSv$$