Physics, Applied Anatomy, and Procedures In-Service Exam Review

Comprehensive practice flashcards covering medical physics, imaging modalities (X-ray, CT, MRI, Ultrasound, Nuclear Medicine), anatomy, and radiation protection.

Posteroanterior (PA) chest radiograph

A radiograph where the x-ray beam passes through the back of the patient and exits through the front to expose a detector positioned against the chest.

Computed radiography

A form of radiography that utilizes a phosphor imaging plate which interacts with x-rays to capture a latent image.

Fluoroscopy

A technique that enables real-time radiographic visualization of moving anatomic structures.

Source-to-image distance (SID)

The standardized distance for an upright chest radiograph, which is given as $183\,cm$.

Scatter grid

The most widely used technology for reducing scattered radiation emanating from the patient.

Bucky grid

The method considered the gold standard in scatter reduction techniques.

Transmission imaging

Imaging in which the energy source is outside the body on one side, and the energy passes through the body to be detected on the other side.

Projection imaging

A type of imaging where each point on the image corresponds to information along a straight-line trajectory through the patient.

Screen film Mammography

The modality with the highest spatial resolution in radiology.

Pair production

The type of x-ray and gamma-ray photon interaction with matter utilized in nuclear medicine.

Absorbed dose

A radiological quantity that does NOT use Sievert ($Sv$) as the system international (SI) unit.

Anechoic

The ultrasound appearance of a totally homogeneous medium which encounters no interfaces to reflect sound.

Strain Elastography

A technique involving the measurement of longitudinal tissue displacement before and after compression, usually by manual manipulation of the transducer.

Reverberation artifact

Artifacts that arise when the ultrasound signal reflects repeatedly between highly reflective interfaces usually near the transducer.

Piezoelectricity

The process by which a transmitter converts electric energy to mechanical energy and vice versa in an ultrasound transducer.

Power Doppler

An ultrasound technique using a color map that does not provide information on flow direction or velocity and is less angle-dependent.

M-mode

An echo display mode used specifically in the evaluation of moving organs like myocardium and valve leaflets.

Grating lobes

Artifacts resulting from ultrasound energy emitted far off-axis by multi-element arrays as a consequence of the noncontinuous transducer surface.

Twinkling artifact

A rapidly changing mixture of colors seen distal to a strong reflector, such as a calculus, often mistaken for an aneurysm.

Projection

In CT, the data collected at a specific angle of interrogation of the object.

Bow tie filter

A component in CT that reduces the intensity of the incident x-ray beam in the periphery of the x-ray field.

Spiral scan

A type of CT scanning where the table moves at a constant speed while the gantry rotates around the patient.

Focal spot blooming

The increase in size of the x-ray focus.

View aliasing

An artifact caused by having too few projection images to reconstruct a high frequency object in the CT image.

Pitch greater than 1.0

A setting in spiral CT that results in a lower radiation dose to the patient.

Beryllium

The material used for the tube port window of a mammography machine.

Becquerel (Bq)

The system international (SI) unit for radioactivity.

Alpha particle

A particle that is identical to the Helium nucleus.

Technetium-99m

The radionuclide accounting for more than $70\%$ of all imaging studies utilizing radionuclides.

Chemotaxis

The mechanism of localization involving the movement of a cell, such as a leukocyte, in response to a chemical stimulus.

Scintillation camera

The most common nuclear imaging device, also known as the Anger camera.

Larmor equation

An equation showing the dependence between the magnetic field and precessional frequency, expressed as $W_0 = B_0$.

Transverse magnetization ($M_{xy}$)

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

Short Tau Inversion Recovery (STIR)

An MRI pulse sequence using a very short TI ($140\text{ to }180\,ms$) to reduce distracting fat signals.

MRI Acquisition time formula

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

Susceptibility artifacts

MRI artifacts occurring at tissue-air interfaces causing signal loss due to rapid dephasing ($T_2^*$).

Wrap-around artifact

An MRI result of mismapping anatomy that lies outside of the FOV but within the slice volume, displacing it to the opposite side.

Segment VII

The superior posterior segment of the right hepatic lobe according to the Couinaud classification.

Pterygopalatine fossa

A small complex space of the deep face shaped like an inverted pyramid, posterior to the maxillary sinus.

Peripheral zone

The zone in the prostate gland where the majority of cancer occurrences are found.

Optimization

The principle followed by the ALARA (As Low As Reasonably Achievable) concept in radiation protection.

Fetal dose limit

The dose to the fetus of a declared pregnant radiation worker, which may not exceed $5\,mSv$ (0.5 rem) over 9 months.

Protective apron thickness

A garment with a typical lead equivalent thickness of $0.25\text{ to }0.5\,mm$.

Public annual effective dose limit

The maximum annual limit for non-occupational persons, set at $1\,mSv$.