Math formulas Flashcards by carlos cordova

what is the inverse square formula? I1-D2 - 2

(I1/I2) = (D2/D1)^2

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what’s the formula to see if its underused or overdosed? ( 2 slices )

(ssd1/ssd2)^2

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what the direct proportions formula? ( F shelly)

(FS1/FS2) = (SSD1/SSd2)

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what’s the central axis formula? (find doses besides PDD) no cross dressing for A and B

DoseA/ DepthA = Dose B/ Depth B

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What is the formula for PDD? ( max is under 100 ft below the the deck

PDD = (Absorbed dose at depth/Aboserbed dose at dmax) x 100

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what is the Maynor F formula? no max on deck

Maynor F = ( ssd(new) + dmax)/(Ssd(old)+dmax) x (Ssd(old) + depth / Ssd(new) + depth ) x 2

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What is the formula for new PDD

New PDD = Maynor F x old PDD

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what is the magnification factor? I then O

Image Size/ Object size or SID/SOD

SID - Source to image distance
SOD - source to object distance

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what is the formula for Dose at DMax(applied dose)

Total dose / PDD

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what is the formula for dose at a depth?

Applied dose x pDD of depth

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what is the Gap formula?

gap call = d/2 (L1/ssd1. + l2/ssd2)

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what is the collimator rotation for CSI? (Spine) broke in half by the sun

Arc tan x 1/2 (L1/ssd1)

L1 = length of spine

Ssd = Spine

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what is the couch rotation for CSI? (Brain) - brain broke in half cause he fell from the couch

Arc tan x 1/2(L2/SAdD)

L2 = length of brain field

SAD = BrAin

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what is the equivalent square?

ES = 2(AxB)/ (A+B)

B - perimeter

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what is blocked area Formula?

BS = square root (area of open field) - (area of blocked field)

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what is the field weighing/ Mu weighing formula?

Field weighing/MU = total dose/mu x Weight of field/sum of field

what is the gantry speed formulas?

gantry speed = degrees of arc / MU

what is the therapeutic ratio formula

Therapeutic ratio = normal tissue tolerance/ tumor metal dose

if answer is less than 1 then no its not favorable therapeutic ratio

what is the tissue weighting formula? ME U weight of F / Sum of F

MU x (weight of field/ sum of field)

What is the wedge angle?

Wedge angle = 90 - Hinge angle/2

wedge angle - angle of the actual wedge angle

what is the hinge angle ?

Hinge angle = 180 - (Wedge angle x2)

angle between gantry angles

What is the HVL formula?

.693/M. - ??

m - coefficient

what is the temperature correct formula ?

(f + 273)/295 x (760/p)

temperature change F to celcius

TC = (Tf -32) x (5/9)

what are the MU calculations? SSD

Dose/ PDD x everything else

what is the wedge factor formula? beam shaping

dose With wedge factor / dose with out wedge factor

what is the Oxygen formula?

OER = Oxgen with O / Oxygen with o

What are the MU cal for SAD

SAD = dose/ TAR x everything else

What is the Extende distance (Inver square formula?

ISF = (Calibrated Ssd + depth / Extended SSD + depth) ^2

what is the Work load factor formula?

Work load = number of patients x dose at 1m per week

What is the electrons line 80% inside line formula?

80% inside line = Mev/3

what is the electron line at 90% Line formula?

90% isode line = Mev/4

what is the useful range formula ?

Useful range = Mev/2

Electron cutout thickness in mm

(MeV/2 ) + 1

what is the activity formula

AF = Ao(.5) ^ t/ T1/2

what is the half life formula

.693/l

what is the mean life formula?

1.44 x (T 1/2)