Three-dimensional radiation dosimetry using polymer gel and solid radiochromic polymer: From basics to clinical applications

Table 1 Summary of polymer gel dosimeter

Dosimeter name	Type	Base	Monomer	Crosslinker	Catalyzer/stabilizer	Scavenger/antioxidant	Key investigator	Country	Ref.
BANANA	PAG	Agarose	Acrylamide	BIS		Nitrous oxide	Maryanski	United States	[58]
BANG	PAG	Gelatin	Acrylamide	BIS		Ammonium-persulphate, TEMED	Maryanski	United States	[59,60]
BANG-2	PAG	Gelatin	MAA	BIS	Sodium Hydroxide	AA	Maryanski	United States	[42]
BANG-3	MAG	Gelatin	MAA		CuSO4-5H2O	AA	Maryanski	United States	[61]
MAGIC	MAG	Gelatin	MAA		CuSO4-5H2O, Hydroquinone	AA	Gore	United States	[5]
MAGAT	MAG	Gelatin	MAA			THPC	Baldock	Australia	[62]
nPAG	PAG	Gelatin	Acrylamide	BIS		THPS	De Deene	Belgium	[63]
nMAG	MAG	Gelatin	MAA			THPS	De Deene	Belgium	[63]
nMAG	MAG	Gelatin	MAA			THP	Ceberg	Sweden	[64]
MAGIC-f	MAG	Gelatin	MAA	Formaldehyde	CuSO4-5H2O	AA	Baffa	Brazil	[65]
HEA		Gelatin	HEA	BIS			Baldock	Australia	[66]
VIPAR		Gelatin	VIPAR	BIS			Pappas	Greece	[67]
NIPAM		Gelatin	NIPAM	BIS		THPC	Schreiner	Canada	[68]
Genipin gel	MAG	Gelatin	MAA, genipin			Sulfuric acid	Jordan	Canada	[69]
LCV micelle radiochromic gel		Gelatin	LCV, surfactant-Triton, TCAA	Formaldehyde			Jordan	Canada	[70]
PAG	PAG	Gelatin	Acrylamide	BIS	NaI	THPC	Elleaume	France	[71]
nMAG	nMAG	Agarose, Gelatin	MAA			THPC	Yoshioka	Japan	[72]
nMAG	nMAG	Gelatin	HEMA, TGMEMA, 9G			THPC	Hiroki	Japan	[73]
Radiochromic gel	RGD	Gelatin	SDS, Chloroform, TCAA		LMG dye		De Deene	Australia	[10]

BIS: N,N’-methylene-bis-acrylamide; MAA: Methacrylic acid; AA: Ascorbic acid; THPC: Tetrakis (hydroxymethyl) phosphonium chloride; THPS: Tetrakis (hydroxymethyl) phosphonium sulfate; NIPAM: N-isopropylacrylamide; LCV: Leuco crystal violet; TCAA: TriChloro Acetic Acid (CCl3COOH); VIPAR: N-vinylpyrrolidone argon; HEA: 2-hydroxyethylacrylate; HEMA: 2-hydroxyethyl methacrylate; TGMEMA: Triethylene glycol monoethyl ether monomethacrylate; 9G: Polyethylene glycol 400 dimethacrylate; SDS: Sodium dodecyl sulfate.

Table 2 Summary of ferrous gel dosimeter

Dosimeter	Type	Base	Monomer	Key investigator	Country	Ref.
Fricke	Fluid	None	Ammonium ferrous sulfate	Gore	United States	[11]
FeMRI	FGD	Agarose	Seaplaque, seagel	Olsson	Sweden	[74]
PVA-FX	FGD	Hydrogel	PVA, FBX	Chu	Canada	[75]
FAX	FGD	Agarose	XO, ferrous	Leong	Malaysia	[76]
FX	FGD	Gelatin	Ferrous ammonium sulfate, XO, sulfuric acid	Jordan	Canada	[70]
PVA cryogel	FGD	Hydrogel	FBX, PVA, dimethyl sulfoxide	Eyadeh	Canada	[77]
XO-PVA	FGD	Hydrogel	PVA, XO, ferrous sulfate, sulfuric acid	Trapp	Australia	[78]
NC-FG	FGD	Gelatin	Nano-clay, ammonium iron (II) sulfate, Perchloric acid	Maeyama	Japan	[41]

PVA: Polyvinyl alcohol; XO: Xylenol orange; FBX: Ferrous benzoic xylenol orange (= ferrous ammonium sulfate, XO, H2SOF4); FGD: Ferrous gel dosimeter; MRI: Magnetic resonance imaging; NC-FG: Nano-composite Fricke gel.

Table 3 Summary of solid plastic dosimeter

Dosimeter	Type	A	B	Initiator	Dye	Key investigator	Country	Ref.
SPD	SPD	Diacetylene	Ethyl trichloroacetate, heptachloropropane, etc.	Radiochromic (fuschin cyanide, etc.)	Leuco crystal violet, or LMG	Patel	United States	[79]
PRESAGE	SPD	Polyol_A, diasocyanate	Polyol_B	Carbon tetrachloride, methylene chloride, tetra-chloroethane, Chloroform	LMG	Adamovics	United States	[6]
PRESAGE	SPD	Crystal clear A	Crystal clear B	Carbon tetrachloride	LMG	Hashemi	Iran	[80]
PRESAGE	SPD	Crystal clear A	Crystal clear B	Chloroform, bromoform, or iodoform	LMG	Geso	Australia	[81]
PRESAGE	SPD	Crystal clear A	Crystal clear B	Bromoform	LMG	Watanabe	United States	[14]

LMG: Leuco-malachite green; SPD: Solid plastic dosimeter.

Table 4 Water equivalency of three-dimensional dosimeters

Dosimeter	Type	Relative effective atomic number	Relative mass density	Relative electron density
PAGAT	PGD	1.0131	1.0264	0.9284
MAGAT	PGD	1.0141, 0.9843	1.0323	0.9933
nMAG	PGD	1.0181
MAGIC	PGD	1.0181, 0.9873	1.0373	0.9903
Genipin gel	PGD	1.0142	1.0012	0.99822
PRESAGE-A	SPD	1.0372	1.0542	0.9772
Water		1.00 (Zeff = 7.42)	1.000	1.0 (3.343 × 1023 Electrons/g)

The numbers in parentheses indicate the references.

¹Ref. [82] (for 18MeV photon energy);

²Ref. [83];

³Ref. [84];

⁴Ref. [85]. PGD: Polymer gel dosimeter; SPD: Solid plastic dosimeter.

Table 5 Comparison of dose quantification techniques

Method	Pros	Cons
MRI	Commonly available at a hospital Easily accessible scan protocol Known accuracy and precision Linear dose response	Low SNR Image artifacts Limited spatial resolution Long scan time
OCT	High spatial resolution Small physical size or compact Easy and free access if owned	Optical artifacts Needs refractive index matching
XCT	Easy access at hospital High SNR Very fast scan	Low image contrast

SNR: Signal-to-noise ratio; MRI: Magnetic resonance imaging; OCT: Optical computer tomography; XCT: X-ray computed tomography.

Table 6 Precision (or uncertainty) of three-dimensional dosimetry[22]

Uncertainty type	Source	Factor	PGD	FGD	SPD
A	Physicochemical	Chemical composition	< 2%		< 2%
		Temperature variation
		Temporal and spatial integrity
	Irradiation	Dose rate
		Energy
		Temperature			2%
		Phantom position setup	1 mm
	MRI	Image noise	< 0.4% (3 mm3)
	OCT	Image noise
	XCT	The standard deviation of CT number	2% to 8%
B	MRI	B0 non-uniformity	< 3%
		B1 non-uniformity
		Gradient non-uniformity
		Temperature during scanning
	Medium	Non-uniform refractive index
	OCT	Refractive index matching
		Unstable light source
		Ambient stray light
		Desynchronization between galvanic mirror and detector
		Misalignment of light, subject, and detector
	XCT	Image processing	5%
		Calibration equation

MRI: Magnetic resonance imaging; OCT: Optical computer tomography; XCT: X-ray computed tomography; FGD: Ferrous gel dosimeter; PGD: Polymer gel dosimeter; SPD: Solid plastic dosimeter.

Table 7 IMRT/VMAT/tomotherapy three-dimensional dosimetry

Ref.	Dosimeter	Read-out method	Treatment site	Delivery type	Photon energy/number of fields	Comparison on the plane or in volume	Gamma index criteria % dose difference (global/local)/DTA (mm)/threshold (%)	Gamma index passing rate
[86]	MAGIC	MRI/T2	Model	IMRT/GKSRS	6MV/Co-60	Volume	3/3/	50.3%
[87]	FX gel	OCT/Vista	Head and Neck	IMRT	6MV	Volume	3/3/none	84.1%
[88]	BANG3	MRI/T2	Prostate	Tomotherapy	6MV/Arc	Volume	3/3	53%
[89]	PRESAGE	DLOS	Brain	IMRT	6MV	Volume	3/3	95%
[90]	MAGIC-f	MRI/T2	Prostate	Tomotherapy	6MV/Arc	Plane	3/3	88.4%
[91]	nPAG	OCTOPUS-IQ	Prostate	IMRT	/7fields	Volume		95.3%
[10]	PAGAT	MRI/T2	Pituitary	IMRT	6MV/7fields	Volume	2/2	99.4%
[33]	BANG3	MRI/T2	Prostate	VMAT (Elekta)	6MV/Arc	Volume	3 (global)/3/25	95.7%
[92]	BANG3	MRI/T2	Prostate	VMAT (Varian)	6MV/Arc	Volume	3 (global)/3/50	90.0%
[93]	PRESAGE	DMOS	Brain	IMRT	6MV/5fields	Volume	3 (global)/3/10	99.4%
[94]	NIPAM	MRI/T2	Eye	IMRT	6MV/5fields	Plane	3/3/	98.5%

MRI: Magnetic resonance imaging; DTA: Distance to agreement; DMOS: Duke Mid-Sized Optical-CT Scanner; DLOS: Duke Large field-of-view Optical-CT Scanner.