Calculators
Sixty-one source-cited calculators across seven modalities
Educational tools, not your department’s dosimetry, treatment-planning system, scanner software or medical physicist.
Most used
18 calculators
The ones a technologist reaches for during a list.
- MR
- eGFRrenal function from creatinine, units and age
- Creatinine clearanceCockcroft–Gault clearance from age, weight and creatinine
- Gadolinium dosevolume in mL from agent and weight
- Scan time (2D)acquisition time from TR, phase steps, NEX, turbo and parallel R
- Fringe field, distance to a target linedistance from a known field, its distance and the target line
- CT & radiotherapy
- DLP and effective doseDLP and mSv from CTDIvol, scan length and region
- Contrast dose by weightvolume in mL from weight, target g I/kg and concentration
- Iodine delivery rateg I/s from concentration, flow rate and volume
- X-ray & radiation dose
- 15% rule (kVp and mAs)new mAs from kVp₁, mAs₁ and the new kVp
- Inverse square & mAs distance compensationnew intensity and the compensating mAs, from intensity, mAs and two distances
- Grid conversionnew mAs from the grid before and the grid after
- Exposure index & deviation indexDI from the achieved EI and the target EI
- Ultrasound
- Gestational age & EDDdating by LMP and by CRL, from LMP, cycle length, scan date and CRL
- Doppler indices (RI, PI, S/D)from PSV, EDV and TAMV
- Doppler velocity & angle correctionvelocity from Doppler shift, transmit frequency and insonation angle
- Nuclear medicine & PET
- Radioactive decayactivity remaining from isotope or half-life, A₀ and elapsed time
- Net injected activitynet MBq from pre-injection and residual
- Paediatric activity (EANM dosage card)activity from weight, baseline and class minimum
Reporting and specialist
22 calculators
For reporting, sonography, mammography, DXA and radiotherapy planning.
- MR
- Inversion time to null a tissueTI from T1, optionally TR-corrected
- MR arthrography dilutiongadolinium and diluent volumes from target, stock and final volume
- Cardiac function & BSAEF, stroke volume, cardiac output and BSA from EDV, ESV, heart rate, height and weight
- ADC from DWIADC from two b-values and their signals
- Fetal weight from MR volumetryweight from fetal volume and density
- CT & radiotherapy
- SSDE (size-specific dose estimate)size-specific dose from CTDIvol, AP, lateral and reference phantom
- BED and EQD2BED and EQD2 from fractions, dose per fraction and α/β
- Alternative fractionationfraction count at a new dose per fraction, from a reference schedule and α/β
- Ultrasound
- Estimated fetal weight (Hadlock IV)weight from BPD, HC, AC and FL
- Mean sac diameterMSD from three sac dimensions
- Volume flowmL/min from vessel diameter and TAMV
- Ankle–brachial indexABI from higher ankle and higher brachial pressure
- Simplified Bernoullipressure gradient from peak velocity
- Ellipsoid volume & PSA densityvolume and PSA density from three dimensions and PSA
- Nuclear medicine & PET
- SUV (body weight)SUV from ROI concentration, injected activity at scan and weight
- Decay to a target activitywaiting time from half-life, current and target activity
- Mammography
- Mean glandular doseMGD per view and per breast, from entrance air kerma, conversion factor and views
- Screening audit metricsrecall rate, CDR, PPV₁₋₃, sensitivity and specificity, from six case counts
- BI-RADS breast densitythe category description and masking risk
- DXA & bone density
- T-score and Z-scoreboth scores from measured BMD and the young-adult and age-matched mean and SD
- Least significant changeLSC and whether a change exceeds it, from your precision and two BMDs
- Precision from a repeated-measures setRMS-SD, %CV and LSC from paired measurements
Physics, teaching and dose in context
21 calculators
Exam preparation and explaining a number to a patient or a student.
- MR
- Pixel / voxel sizepixel and voxel from FOV, matrix and slice
- Relative SNR, before and afterSNR ratio from voxel volumes, NEX, bandwidth and parallel R
- Ernst angleoptimal flip from TR and T1
- In-phase / opposed-phase TEDixon echo times from field B₀
- Larmor frequency & chemical shiftfrequency from field B₀, nucleus and shift
- Relative signal intensitysignal from sequence, T1, T2, TR, TE, TI and flip
- Ellipsoid volume & PSA densityvolume and PSA density from three dimensions and PSA
- X-ray & radiation dose
- Reciprocity & exposure timemAs and the time at a new mA, from mA and time
- Entrance surface dosemGy from tube output, mAs, SSD and backscatter
- Effective dose in contextchest-radiograph and background equivalents from an effective dose in mSv
- Cumulative dose & background equivalenttotal µSv from the number of exposures and the dose each
- Half-value layer attenuationtransmitted fraction from HVL and absorber thickness
- Magnificationmagnification factor and true object size, from SID, SOD and measured size
- Dental: DAP to effective doseµSv from DAP and a coefficient
- Fetal dose in contextthe ACOG band an estimated fetal dose falls in
- Ultrasound
- Mechanical indexMI from peak rarefactional pressure and frequency
- Nuclear medicine & PET
- Activity unitsMBq and mCi, either box drives the other
- Effective dose estimatemSv from radiopharmaceutical or coefficient and administered activity
- Inverse-square dose ratedose rate at r₂ from the rate at r₁ and both distances
- Mammography
- Compression force conversiondaN and lbf from a force in newtons, with the clinical band
- DXA & bone density
- Body composition indicesBMI, FMI and ALMI from weight, height, fat mass and appendicular lean mass
Also on the site
Veterinary
- Veterinary MR calculators and referenceveterinary MR tools and reference, on their own page