Diagnostic Imaging Studies I - Introduction to Radiography

Flashcards covering core vocabulary, definitions, metrics, body habitus types, anatomical landmarks, and positioning terminology for Diagnostic Imaging Studies I.

Radiologic Technology

A healthcare profession encompassing diagnostic imaging technologists and radiation therapists.

Radiographer

A specialized radiologic technologist who administers ionizing radiation to perform radiographic procedures at the request of a licensed medical practitioner.

ALARA Principle

An acronym for "As Low As Reasonably Achievable," requiring radiographers to minimize patient radiation dose while maintaining diagnostic image quality and clinical justification.

AAPM Position on Gonadal Shielding

The recommendation by the American Association of Physicists in Medicine that routine gonadal shielding can degrade diagnostic quality and cause anatomical obstruction, leading to endorsed positions against routine shielding.

Involuntary Motion

Movement caused by muscle actions beyond the patient's conscious control (such as heart pulsation, chills, peristalsis, tremors, spasms, or pain), primarily controlled by using short exposure times.

Voluntary Motion

Movement controlled by the central nervous system under the patient's conscious control (such as breathing or nervousness), controlled through clear instructions, patient comfort, and immobilization devices.

Breathing Technique

Instructing the patient to breathe normally during a long exposure time with a low milliamperage ($mA$) setting to intentionally blur overlying anatomic structures.

Image Receptor (IR)

The device that receives the energy of the X-ray beam and forms an image of the body part.

Solid-State Digital Detector (DR)

A flat-panel image receptor that converts X-ray energy directly or indirectly into a digital signal, offering the fastest image acquisition time ($< 6\,seconds$).

Photostimulable Storage Phosphor Plate (CR)

An image receptor housed in a cassette containing a phosphor plate that stores X-ray energy until scanned by a laser in a dedicated reader to release light and produce a digital image.

Source-to-Image Receptor Distance (SID)

The distance from the anode focal spot inside the X-ray tube to the image receptor; modern standard values are typically $105\,cm$ to $110\,cm$.

Source-to-Skin Distance (SSD)

The distance between the focal spot of the X-ray tube and the patient's skin, which NCRP guidelines state shall not be less than $30\,cm$ (absolute minimum) and should not be less than $40\,cm$ (preferred minimum).

Collimation

The restriction of the radiation field to irradiate only the anatomy of interest, which minimizes patient dose and reduces scatter radiation.

Anatomic Position

The standard body posture where the patient stands erect facing forward with arms at sides, palms facing forward, heels together, and toes pointing anteriorly.

Sagittal Plane

A vertical plane running front-to-back that divides the body or body part into right and left segments.

Midsagittal Plane

A specific sagittal plane passing directly through the midline of the body, dividing it into equal right and left halves.

Coronal Plane

A vertical plane running side-to-side that divides the body or body part into anterior (front) and posterior (back) segments.

Midcoronal Plane

A specific coronal plane passing through the body's midline, dividing it into equal anterior and posterior halves (also called the midaxillary plane).

Horizontal Plane

A plane passing through the body at right angles to the longitudinal axis, dividing it into superior and inferior portions (also termed axial, transverse, or cross-sectional).

Oblique Plane

A plane that passes through a body or body part at any angle relative to the sagittal, coronal, or horizontal planes.

Interiliac Plane

A special plane that transects the pelvis at the top of the iliac crests at the level of the fourth lumbar spinous process, used for positioning the lumbar spine, sacrum, and coccyx.

Occlusal Plane

A special plane formed by the biting surfaces of the upper and lower teeth when the jaws are closed, used in positioning the odontoid process and head projections.

Sthenic Body Habitus

The predominant body habitus type ($50\%$ of population), characterized by an ordinary or average build with a moderately high stomach and moderately transverse heart.

Asthenic Body Habitus

A frail body habitus type ($10\%$ of population) with a long, shallow thorax and a low, medial stomach located deep in the pelvis when standing.

Hypersthenic Body Habitus

A massive body habitus type ($5\%$ of population) characterized by a short, broad, deep thorax and a high, transverse stomach in the middle of the abdomen.

Hyposthenic Body Habitus

An intermediate body habitus type ($35\%$ of population) between sthenic and asthenic, forming part of the $85\%+$ majority of ordinary clinical presentations.

Radiographic Projection

The path of the central ray as it exits the X-ray tube, passes through the patient, and reaches the image receptor (e.g., Anteroposterior or Posteroanterior).

Radiographic Position

The specific physical placement or overall posture of the patient's body or body part in relation to the table or image receptor (e.g., Right Lateral, LPO, Upright).

Radiographic View

The body part as seen from the perspective of the image receptor when evaluating the finished radiograph.

Radiographic Method

A specific radiographic projection named after the individual who developed or popularized it (e.g., Waters method, Towne method).

Abduction

Movement of a body part sideways away from the central axis of the body.

Adduction

Movement of a body part inward toward the central axis of the body.

Dorsiflexion

Flexion or bending of the foot upward toward the leg.

Plantar Flexion

Bending of the foot downward toward the sole.

Eversion

Outward turning of the foot at the ankle joint so that the sole faces away from the midline.

Cervical Vertebrae Surface Landmarks

External landmarks for positioning the cervical spine: C1 corresponds to the mastoid tip; C2/C3 to the gonion; C3/C4 to the hyoid bone; C5 to the thyroid cartilage; and C7/T1 to the vertebra prominens.

Thoracic Vertebrae Surface Landmarks

External landmarks for positioning the thoracic spine: T2/T3 corresponds to the jugular notch; T4/T5 to the sternal angle; T7 to the inferior angles of the scapulae; and T9/T10 to the xiphoid process.

Lumbar and Pelvic Surface Landmarks

External landmarks for positioning: L2/L3 corresponds to the inferior costal margin; L4/L5 to the superiormost aspect of the iliac crests; S1/S2 to the ASIS; and the coccyx to the pubic symphysis and greater trochanters.

Oblique Position Abbreviations (LAO, LPO, RAO, RPO)

Abbreviations designating the body surface and side closest to the IR: Left Anterior Oblique (LAO), Left Posterior Oblique (LPO), Right Anterior Oblique (RAO), and Right Posterior Oblique (RPO).

Abdominal Quadrant Abbreviations (RUQ, LUQ, RLQ, LLQ)

Abbreviations for the four anatomical divisions of the abdomen: Right Upper Quadrant (RUQ), Left Upper Quadrant (LUQ), Right Lower Quadrant (RLQ), and Left Lower Quadrant (LLQ).