Radiation Dosimetry and CT

These flashcards cover essential vocabulary and concepts related to radiation dosimetry and CT imaging as discussed in the lecture.

Effective Dose

The dose that takes into account the type of tissue being irradiated and its radiosensitivity.

CTDI

CT Dose Index; an estimate of the MSAD using a single slice and assuming no gaps or overlaps between slices.

DLP

Dose Length Product; the product of the CTDI volume and the scan length, accounting for variations in individual anatomy.

Scatter Radiation

Radiation that is deflected in different directions when it strikes an object, affecting dose mapping.

KVP

Kilovolt peak; a measurement of the maximum voltage applied to an X-ray tube that affects the quality and quantity of the X-rays produced.

ALARA

As Low As Reasonably Achievable; the safety principle aimed at minimizing radiation exposure.

Pitch

The ratio of the table motion to the slice thickness in CT imaging, affecting dose and image quality.

Overbeaming

The collimators in MDCT being wider than the active detectors to ensure uniform exposure over the entire area scanned.

Quality Factor (Q Factor)

A dimensionless factor used to account for the biological effectiveness of different types of radiation.

KERMA

Kinetic Energy Released in Matter; the energy transferred from photons to charged particles per unit mass.

MSAD

Multi-Scan Average Dose; the average dose across multiple overlapping slices accounting for scatter.

ImageGently

A campaign aimed at educating providers on radiation safety in pediatric imaging.

ImageWisely

A campaign focused on optimizing imaging examinations to use only the necessary radiation for quality images.

Radiation Absorbed Dose (rad)

The amount of energy absorbed per unit mass due to radiation exposure.

Rem

Rankin equivalent man; a unit of dose equivalent that accounts for biological effects from radiation.

Collimation

The technique of narrowing the X-ray beam to reduce patient exposure and improve image quality.

Bergonié and Tribondeau Law

States that tissues are more radiosensitive based on their level of mitotic activity.

Filtration

The process of removing low-energy X-rays that contribute to patient dose without improving image quality.

Dose Geometry

The spatial distribution of radiation dose, particularly relevant when comparing traditional X-ray and CT imaging.

Modalities

Different methods or technologies utilized for medical imaging, such as X-ray, CT, and MRI.

Pediatric Protocols

Customized imaging protocols designed specifically for the unique needs and sensitivities of pediatric patients.

Density Variation

Differences in tissue densities that can affect attenuation and, consequently, radiation dose.