TABLE 2.

Dosimeter pros and cons.

Detector	Uses a	Pros	Cons	Resource(s)
Gafchromic EBT‐XD Film	TAD BC	Widely utilized DR independent Better dynamic range and lower uncertainty than EBT3 Calibration in CONV Can be cut and shaped to desired size	Large uncertainty (up to 4%) Passive and requires read out time. Usually, 24 hrs. to a week Many calibration measurements required with known dose delivered Orientation effects	Oh et al. 30 Cetnar et al. 37 No et al. 34 Petusseau et al. 38 Rahman et al. 31 Sloop et al. 17 Jorge et al. 28 Konradsson et al. 26 Garty et al. 39 Adrian et al. 40 Deut et al. 41 Konradsson et al. 42 Kyle et al. 35 Lempart et al. 25 Levy et al. 43 Szpala et al. 44 Xie et al. 45
Gafchromic EBT3 Film	TAD BC	Widely utilized DR independent Calibration in CONV Can be cut and shaped to desired size	Large uncertainty (up to 4%) Passive and requires read out time. Usually, 24 hrs. to a week Many calibration measurements required with known dose delivered Worse dynamic range and higher uncertainty than EBT‐XD Orientation effects
OC‐1 OrthoChromic Film	TAD BC	Higher saturation level to dose than EBT3 Better high dose rate performance than EBT3 and EBT‐XD Utilize for high dose measurements	Requires reflection mode scanning	Garty et al 39
microDiamond PTW	TAD BC	Linear response up to 1.5 Gy/pulse Could be used as primary detector for beam characterization (SN 122325) PDDs and profiles agreement with EBT3 Gafchromic film Could be used to measure output factors and output vs gantry angle	Above 1.5 Gy/pulse is uncertain Required cross calibration There is another more optimized model from PTW flashDiamond	Dal Bello et al 23
Edge Diode SNC 1118 (N‐Type)	TAD BC DPP	Linear response DR, energy, and DPP independent Good temporal resolution (0.1 ms) Comparable to IC in terms of precision No recombination correction Agreement with EBT‐XD Gafchromic film to within 3% Energy independent within 4% of film Good SR Dose conversion given Agreement with W1 scintillator within ‐7 to 5% Tested during ramp up as well (various DPP) and had 4.5% error bars (only due to threshold setting with device) Independent of repetition rate	Film has a higher SR Lost 0.4% per kGy of sensitivity Needs further characterization Electrometer requires customization (simple and provided by manufacturer though) Not tested above 0.78 Gy/pulse and 180 Gy/s USB not fast enough to transfer data in real time	Rahman et al 24 Sloop et al 17
EDD 2–3G Diode IBA	PC	Agreement with an external monitor chamber (monitor chamber was able to measure DPP with large uncertainty after corrections applied) Was able to control delivery by # pulses and was accurate every time (> 1000 trials)	Required construction of a MCU to actually count No information on DPP	Lempart et al. 25 Konradsson et al 26
EDP 20–3G Diode IBA	TAD	Can be used to tune a LINAC to FLASH Could be calibrated to measure output in FLASH Linear with dose Linear with DPP compared with film	Study did not mention the calibration procedure	Lempart et al. 25
Ion Chambers	TAD BC	Can provide accurate data for profiles in UHDR Can be used to approximate DR Logistic model can accurately track saturation	Saturation and recombination effects at UHDR outside of clinical tolerance Requires many verification tests alongside other detectors first Requires models to correct for recombination Saturation at “low” DPP Profilers need to be used at a low voltage and far away from the source to compensate	Kyle et al. 35 Oh et al. 36 Poirier et al. 21 No et al 34
W1 Scintillator Exradin	TAD DPP	Agreement with film measurements Independent of DR up to 360 Gy/s, DPP up to 1.1 Gy/pulse, and FS Microsecond temporal resolution	Major damage issues of 16.2% loss / kGy (declines after accumulation of more dose) Recalibration required almost every use Must account for Cherenkov production Tedious calibration (10 measurements, 2 factors)	Ashraf et al 29
W2 Scintillator Exradin with MAX SD	TAD	Agreement with 2% of film MAX SD corrects for Cherenkov itself Smaller model linear with dose up to the max settings of the LINAC No pulse repetition frequency non‐linearity	MAX SD required modifications by vendor (otherwise saturates) Large volume model saturates at “low” DPP Optical fiber damages 2% per kGy	Oh et al. 30
TLDs	TAD	Close agreement with EBT3 film Calibration can be traced to primary standard Reproducible response with different total dose at high DPP DR independent (up to 3 × 10^5 Gy/s)	Requires correction factors for electrons Farther off from dose than film and alanine in UHDR For short SSD, may require energy correction Some sensitization effects	Motta et al 27 Jorge et al 28
OSLDs	TAD	Reproducible response with different total dose at high DPP DR independent (up to 3 × 10^5 Gy/s) Al2O3:C was most precise—agreement with film within 3%	There was a BeO OSLD with a higher sensitivity that was affecting the DR plots (package to package variability) Conflicting results with Al2O3:C across studies Some sensitization effects	Motta et al 27
Alanine Pellets	TAD	Close to the expected dose (more than TLD and film in the study) in UHDR Agreement to film within 2% Reproducible	Farther off in dose from film and TLD Study had no absolute reference, results may need further testing Passive, requires EPR	Jorge et al 28
Quad Channel CXP‐12 GigaSens (Concurrent EDA) CMOS Camera	BC RPP	Can gate to LINAC signal and match repetition rate with capture Excellent SR Temporal resolution to capture each pulse Used in vivo Can maybe obtain estimates of dose, DR, and DPP Picks up respiratory motion effects on DPP when utilized in vivo Worked up to 360 Hz (FPS was matched to 360) Can provide spatial dose distribution info on a pulse‐by‐pulse basis, not just total dose	Low SNR without intensifier Intensifier reduces SR Optical scattering causes measured profile to extend out of the treatment field Requires dark and flat field corrections Requires median filtering Did not convert pixel density to dose No information on DPP	Rahman et al 33
DoseOptics iCMOS Camera	TAD BC	Linear response Dose rate independent (tested up to 400 Gy/s) DPP independent (tested up to 0.91 Gy/pulse) Scintillation imaging was better than Cherenkov, especially with bandpass filtering Good SR Can reconstruct or directly measure profiles/PDDs per pulse Can achieve high passing rates for certain profiles against film High spatial resolution (1 mm^3)	Cherenkov did not work for PDDs/ profiling due to lateral scatter Technique needs further improvement based on optical alignment, better viewing, speed Must filter Cherenkov signal from Scintillation signal due to energy dependance cintillation requires a quinine sulfate solution Disagreement with films on PDD buildup and some profiles Applicator leakage imaging to remove Lots of processing steps	Ashraf et al. 32 Rahman et al 31
HC‐120 PMT with OF read with 3000 series Picoscope	PC	DR independent Linear with dose (up to 200 Gy tested) and DR (up to 300 Gy/s tested) (360 Hz) Could be used in place of target signal that tunes the beam	No information on the absolute dose in a pulse Was placed at the edge of the field to just monitor the output pulse by pulse Read out system limits temporal resolution (PMT alone has nan‐second resolution)	Rahman et al 31
Hyperscint RP100 scintillator system	TAD	Comes with integrated software system that tells exactly how to calibrate and upload measurements for calibration, and auto‐removes Cherenkov/background Software has a built‐in pulse counter Linear with dose up to several thousand Gy  < 0.4% signal loss per kGy Agreement to films within 4%	Not all photodetectors are read out simultaneously causes under recording especially if using for dose per pulse (counting) Dose calibration must be performed everyday Temporal resolution is close to that of a 180 Hz beam (2.5 ms)	Poirier et al. 20
Remote Trigger Unit DoseOptics	PC	Pulses measured matches expected for low frequencies	Positional dependance with respect to the field PC has some errors in higher repetition rates (maybe due to lag in gating—see control system section) Decay time causes issues	Ashraf et al. 29 Rahman et al. 16

^a Uses of detectors are one of the following options: Total absorbed dose (TAD), beam characteristics (BC), dose per pulse (DPP), reading per pulse (RPP, same as DPP but not calibrated), or pulse counting (PC).