Variable at the 10th fraction

∆Vol_{10fr}(%)

∆Vol_{post}(%)


Spearman’s Rho

pvalue

Spearman’s Rho

pvalue


ADC

0.121

0.285

0.103

0.383

D_{t}

0.286

0.011

0.289

0.013

F

−0.057

0.614

−0.232

0.047

D*

−0.114

0.314

0.122

0.299

D* × f

−0.153

0.176

−0.013

0.910

∆ADC

0.228

0.042

0.173

0.141

∆D_{t}

0.319

0.004

0.372

0.001

∆f

0.022

0.844

−0.242

0.038

∆D*

−0.117

0.301

0.192

0.101

∆D* × f

−0.119

0.293

0.096

0.416

 Statistically significant pvalues are bold. Abbreviations: ∆Vol_{10fr} Parotid shrinkage(%) at the 10th fraction, ∆Vol_{post} Parotid shrinkage(%) 8 weeks after RT, ADC Apparent diffusion coefficient, D_{t} Tissue diffusion coefficient, D* Perfusionrelated diffusion coefficient, f(%) Perfusion fraction, D* × f Product of D* by f, ∆ADC ADC variation (%) relative to the pretreatment value (analogously for the other imaging variables)