Patient Positioning, Radiography, and Radiation Safety Review

Comprehensive flashcards covering patient positioning, anesthesia/imaging physics, vital signs, and radiation safety standards as detailed in the lecture transcripts.

What is the Prone position and when is it often used?

The patient is lying on their stomach with the head turned to the side; it allows for mouth drainage after oral surgery.

How is the Sim's Position described?

The patient lies on the Left or Right side on the bed with a pillow between the legs for comfort.

What are the specific angles for Semi-Fowler's and Low Fowler's positions?

Semi-Fowler's involves elevating the head of the bed to $30-60^{\circ}$, while Low Fowler's is $15-30^{\circ}$.

What is the purpose of the Lithotomy position?

The patient lies flat on their back with legs elevated by stirrups; it is used for GYN procedures.

Compare Trendelenburg and Reverse Trendelenburg positions.

Trendelenburg is lying supine with the head below the feet (helped to increase BP), while Reverse Trendelenburg is lying supine with the head above the feet (promotes perfusion in obese patients during surgery).

What is the main goal of radiography?

To produce a diagnostic radiograph on the first attempt to reduce exposure, decrease costs, and produce data quickly.

How are x-rays produced in an x-ray tube?

Electrons in the cathode undergo thermionic emission, and the resulting photons collide with the anode at a high rate of speed.

What is the energy distribution when photons collide with the anode?

$99\%$ heat and $1\%$ x-rays.

What is the typical target angle for the anode and why?

The target is angled at $11-15^{\circ}$ to direct the beam.

What determines radiographic density and radiographic contrast?

Radiographic density is primarily affected by mAs (amount of photons), while radiographic contrast is primarily affected by kV (penetrating/pushing power).

How should mAs and kV be adjusted if a film is underexposed?

Increase mAs by $30-50\%$ or increase kV by $10-15\%$. If contrast is okay, adjust mAs; if contrast is not okay, adjust kV.

What is the difference between Stochastic and Deterministic radiation effects?

Stochastic (somatic) effects occur by chance and are determined by dose, while Deterministic (nonstochastic) effects are noticeable in the short term, such as a sunburn.

Define Linear Energy Transfer (LET).

The rate at which energy is transferred from ionizing radiation into tissues; higher LET means a greater amount of energy is transferred per interaction.

At what stage of pregnancy is the fetus most susceptible to ionizing radiation?

Between $2-10$ weeks, which is the period of major organogenesis.

What is the Maximum Permissible Dose (MPD) for an occupationally exposed person?

The MPD is $5\,\text{rem/year}$ or $0.05\,\text{Sv/year}$.

What are the three major factors of ALARA?

Distance (intensity is inversely related to distance), Time (reducing exposure time), and Shielding (PPE).

What are the lead equivalent requirements for aprons and gloves at $150\,kV$?

Leaded aprons must provide attenuation equivalent to at least $0.5\,mm\,Pb$, and protective gloves must provide at least $0.2\,mm\,Pb$.

What are the temperature ranges for Oral, Rectal, and Axillary measurements?

Oral: $97.6-99.6^{\circ}F$; Rectal: $98.6-100.4^{\circ}F$; Axillary: $96.6-98.6^{\circ}F$.

How is blood pressure categorized as Normal, Pre-hypertension, and Hypertension?

Normal: $100-120/60-79$; Pre-hypertension: $120-139/80-89$; Hypertension: $>140/>90$.

What are the SPO2 levels for the categories of hypoxia?

Mild Hypoxia: $90-94\% \, SPO_{2}$; Moderate Hypoxia: $86-89\% \, SPO_{2}$; Severe Hypoxia: $<86\% \, SPO_{2}$.

What are the absorbed dose thresholds for sperm depression and hair loss?

Sperm Depression: $100\,mGy$ ($0.1\,Gy$); Hair loss/Alopecia/Epilation: $3,000\,mGy$ ($3\,Gy$).

What is the formula for Effective Dose (EfD)?

$EfD = D \times W_{R} \times W_{T}$, where D is Absorbed Dose, $W_{R}$ is Radiation Weighting Factor, and $W_{T}$ is Tissue Weighting Factor.

In an image intensifier tube, what are the input and output phosphors made of?

The input phosphor is made of cesium iodide (CsI) and the output phosphor is made of zinc cadmium sulfide.

What is the conversion for the radiation unit 'Roentgen' to SI units?

$1\,R = 2.58 \times 10^{-4}\,C/kg$ of air.

What is the annual whole body effective dose limit for occupational exposure according to the NCRP?

$50\,mSv$.