Calculating pt dose Using Nomigrams Sensitivity to Radiation & more “math/dose ” problems. Bush Ch 36 & 31,32 & Stat Ch 8 Rev 2013 - week 7 - day 1 & 2. This family of curves is a nomogram for estimating output x-ray intensity from a single-phase radiographic unit.
Calculating pt doseUsing NomigramsSensitivity to Radiation& more “math/dose ” problems
Bush Ch 36 & 31,32
& Stat Ch 8
Rev 2013 - week 7 - day 1 & 2
estimate the ESE from a lateral skull film taken at 66 kVp, 150 mAs, with a radiographic unit having 2.5 mm Al total filtration.
Estimate the intersection between a vertical line rising from 2.5 mm Al and a horizontal line through 66 kVp. Extend the horizontal line to the y-axis and read 3.8 mR/mAs
3.8 mR/mAs × 150 = 570 mR
A better approach requires that a medical physicist construct a nomogram such as that shown in Figure 40-4 for each radiographic unit. A straight edge between any kVp and mAs value will cross the ESE scale at the correct mR value.
1.The x-ray unit or units used for the study
2.The projections taken
3.The number of films associated with each projection
4.Each projection's technical exposure factors (kVp, mAs, image receptor size)
5.The SID for each view
6.The patient's AP or lateral dimensions at the site of each projection
7.For fluoroscopic irradiation, the approximate kVp, mA, and especially the duration
8.For spot films, the number taken, the kVp and mA selected, and the approximate exposure time
How do you calculate dose for exam?
TABLE 37-1 Representative Radiation Quantities From Various Diagnostic X-ray Procedures
Page 566 10TH ed
Bone and teeth
TABLE 3-3 Organ or Tissue Weighting Factors
Two of the most radiosensitive
tissues with rapidly dividing cells
in the body is ____ tissue.
Which one is most SENSITIVE
CELLS THAT REPRODUCE THE MOST – SPEND THE MOST TIME IN THEIR REPRODUCTIVE STATE