Table 1.

SAR_10g-based metrics used for the evaluation of the quality of the targeted RF heating.

Indicator	Location	Description	Unit	Valid Value	Equation
SAR10g	Whole Head	SAR10g averaging over cubes covering 10 g of tissue (SAR10g) distributions inside the human head voxel model Duke $SAR={\displaystyle \frac{\sigma {\left|E\right|}^2}{2\rho }}$; σ (S/m) is the electrical conductivity, ρ (kg/cm3) is the mass density, and |E| (V/m) is the magnitude of the local electric field vector	W/kg	<40 (HR)	(6)
				<80 >40 (TR)
TCxx (TC25/TC50/TC75) [70,71,72]	TR	Measures the percentage of volume with SAR10g over 25% (TC25), 50% (TC50) or 75% (TC75) of SAR10g,max found in the TR. This is only evaluated if SAR10g,max >40 W/kg. $T{C}_{xx}={\displaystyle \frac{voxe{l}_{TR}{|}_{{{\mathrm{S}\mathrm{A}\mathrm{R}}_{10\mathrm{g}}>\mathrm{x}\mathrm{x}.\mathrm{S}\mathrm{A}\mathrm{R}}_{10\mathrm{g},\mathrm{m}\mathrm{a}\mathrm{x}}}}{\mathrm{t}\mathrm{o}\mathrm{t}\mathrm{a}\mathrm{l}voxe{l}_{TR}}},\mathrm{x}\mathrm{x}=\mathrm{25,50,75}$	%	>75 [54]	(7)
* Off-TCxx (off-TC25/off-TC50/off-TC75)	HR	iso-SAR contour in healthy tissue defined as off-target regions (off-TR). Measures the percentage of voxels in the HR with SAR10g over the (25%, 50%, and 70%) of the SAR10g,max found in HR (healthy constraint SAR10g (40 W/kg))). $off-T{C}_{xx}={\displaystyle \frac{voxe{l}_{HR}{|}_{{{\mathrm{S}\mathrm{A}\mathrm{R}}_{10\mathrm{g}}>\mathrm{x}\mathrm{x}.\mathrm{S}\mathrm{A}\mathrm{R}}_{10\mathrm{g},\mathrm{m}\mathrm{a}\mathrm{x}}}}{\mathrm{t}\mathrm{o}\mathrm{t}\mathrm{a}\mathrm{l}voxe{l}_{HR}}},\mathrm{x}\mathrm{x}=\mathrm{25,50,75}$	%		(8)
SAR10g Amplification Factor (SAF) [10,70,73]	Whole Head	Measures that healthy tissue preservation from mean SAR10g in HR $\mathrm{S}\mathrm{A}\mathrm{F}={\mathrm{S}\mathrm{A}\mathrm{R}}_{10\mathrm{g},\mathrm{m}\mathrm{e}\mathrm{a}\mathrm{n}}\left(\mathrm{T}\mathrm{R}\right)/{\mathrm{S}\mathrm{A}\mathrm{R}}_{10\mathrm{g},\mathrm{m}\mathrm{e}\mathrm{a}\mathrm{n}}\left(\mathrm{h}\mathrm{e}\mathrm{a}\mathrm{l}\mathrm{t}\mathrm{h}\mathrm{y}\right)$	-		(9)
Homogeneity Coefficient (HC) [70]	TR	Measures how homogenous the SAR10g,max is distributed over TR	-
		$HC\left(TR\right)=TC\left(75\right)/TC\left(25\right)$	-		(10)
* Homogeneity Coefficient (off-HC)	HR	Measures how homogenous the SAR10g,max in healthy tissue is distributed over HV.	-
		$\mathrm{o}\mathrm{f}\mathrm{f}-\mathrm{H}\mathrm{C}\left(\mathrm{H}\mathrm{V}\mathrm{R}\right)=(\mathrm{o}\mathrm{f}\mathrm{f}-\mathrm{T}\mathrm{C}(75\left)\right)/(\mathrm{o}\mathrm{f}\mathrm{f}-\mathrm{T}\mathrm{C}(25\left)\right)$	-		(11)
* Total Homogeneity Coefficient (THC)	Whole Head	Measures total homogeneity of SAR10g inside the TR and HR to satisfy hyperthermia treatment goals	-
		$HC\left(TR\right)=HC.\mathrm{o}\mathrm{f}\mathrm{f}-\mathrm{H}\mathrm{C}$	-		(12)
Performance Indicator (PI) [72]	Whole Head	Measures the total performance of each hyperthermia treatment planning	-
		$PI=SA{R}_{\left(10g,max\right)}{|}_{TR} .SAF.TC$	W/kg		(13)
Txx (T10/T50/T90) [54,72]	TR	In clinical practice, the assessment of tumor coverage should involve the examination of indexed temperatures, specifically T10, T50, and T90. These values correspond to the temperatures reached in at least 10%, 50%, and 90% of the target region, respectively.	°C	T50 > 40	(14)

* These indicators are defined for this work.