Physics Equations and Constants - Part 1

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1. Compton Equation (Energy) 2. Compton Equation (Wavelength)
• • 3. Capacitor
• Q=CV
• 4. Resistor
V=IR
5. Inductor 6. Resistance
• • R = resistance
• = resistivity
• L = length
• A = cross-sectional area
7. Doppler Shift
• • 8. T1/T2 images
• T1 = fat bright
• T2 = water/fluids bright
9. Detector Dead Time Correction
• (non-paralyzable)
• (paralyzable)
10. Exposure to Kerma
• • X • Na = 6.02x1023 atoms/mol
12. Roentgen to C/kg
R = 2.58x10-4 C/kg
13. Curie to Bq
1 Ci = 3.7x1010 Bq
14. Kerma from attenuation coefficient 15. Bits to Bytes
8 bits = 1 byte
16. Transmission, Attenuation
• • 17. kB, MB, GB, TB
• kB = 210 bytes
• MB = 220 bytes
• GB = 230 bytes
• TB = 240 bytes
18. Radiation Protection Barrier Transmission
• • • 19. Film Gamma or Average Gradient 20. Electric Field and Voltage  21. Special Relativity
• • • • 22. decibels
• • 23. Radioactive Decay, Half Life
• • • 24. Magnification 25. Dose Equivalent, Effective Dose
• • 26. Average energy of beta decay particle
1/3 of the max energy
27. Gyromagnetic Ratio and Larmor Frequency
• Gyromagnetic ratio for protons (H in water): • Larmor Frequency: or 28. Survival Fraction (Single target, Single hit) (Multiple target, Single hit) (Single target) (Multiple Target)
29. Ion Chamber Temperature and Pressure Correction 30. Transient Equilibrium Activity of Daughter
• • Note: after about 4 Half-lives, the daughter is approximately in equilibrium with the parent. If branching ratio is 1, then the daughter has a slightly higher activity than the parent.
31. Neutron beam activation saturation activity
• • 32. Temperature Conversions (Celsius to Kelvin, Celsius to Fahrenheit)
• T[K] = T[C] + 273.15
• T[F] = 9/5 T[C] + 32
33. MeV/c2 to amu conversion
1amu = 931.5 MeV/c2
34. Sensitivity and Specificity; ROC Curve
• Sensitivity = TP/(TP+FN)
• Specificity = TN/(TN+FP)
• ROC Curve is Sensitivity vs (1-Specificity)
35. Hounsfield Unit 36. Exposure from Gamma Constant  37. Fetal Dose Effects
• During pre-implantation (1st week), the most likely result is death
• During organogenesis (2-8 weeks), the most likely result is growth development and malformations
• During early fetal stage (8-15 weeks), the most likely result is mental retardation
• During mid to late fetal stage (15+ weeks), the most likely result is leukemia and other cancers
• Threshold dose is likely around 10 cGy – 50 cGy
38. What process competes with gamma ray emission?
Internal conversion
39. Optical Density Equation 40. What's the phase difference between the two surfaces of a piezoelectric crystal used in US?
• Quarter-wave matching • 90-degree phase difference
41. Snell's Law 42. Speed of sound in fat and soft tissue?
• In fat: 1450 m/s
• In soft tissue: 1540 m/s
43. Specific heat equation
• Specific heat transfer: • Fusion (change in state of matter): 44. Effective half life 45. What standard controls patient demography and billing info?
HL7 (Health Level 7)
46. What regulation controls patient anonymization?
HIPAA
47. What is the lower limit for a fringe field for MRI?
5 Gauss = 0.5 mT
48. An emission has only neutrino and characteristic x-ray, what's the decay scheme?
Electron Capture
49. If a gamma emission from a metastable state to stable state is forbidden, what's the alternative decay?
Internal Conversion
50. Focal Spot Blur
Blur = spotsize*OID/SOD
51. Secular equilibrium ratio of daughter to parent
F = 1-(1/2)n where n is number of half lives
52. Relation between HVL and TVL?
TVL = 3.32 HVL
53. Standard deviation values of Gaussian Distribution
• +/-1 sigma = 68%
• +/-2 sigma = 95%
• +/-3 sigma = 99.7%
54. Electron mass and charge
• Mass = 9.1E-31 kg = 0.511MeV/c2
• Charge = 1.6E-19 C
55. According to NCRP 116 and ICRP report, what is the fatal risk of cancer by radiation for whole population for low dose rate and low LET
5% per Sv of whole body
56. According to FDA, the collimator or jaw of linac is required to be how many HVL layer?
0.5% = 0.005 ~ 8HVL
57. An atom that decays by releasing a positron has an excess of .. (neutrons, protons, electrons)
protons
58. Radiation Dose Limits
• Occupational: 50 mSv/year
• Extremities: 500 mSv/year
• Eyes: 150 mSv/year
• Fetus: 5 mSv/year

Population: 1mSv/year
59. Planck's Constant
h = 6.62E-34 m2kg/s
 Author: Anonymous ID: 166432 Card Set: Physics Equations and Constants - Part 1 Updated: 2012-08-20 02:26:16 Tags: Physics Equations Constants Part Folders: Description: Physics Equations and Constants - Part 1 Show Answers: