Early Treatment Response Monitoring Using 2-Deoxy-2-[¹⁸F]fluoro-D-glucose Positron Emission Tomography Imaging during Fractionated Radiotherapy of Head Neck Cancer Xenografts

Table 2

Accuracy of PET parameters (calculated using the maximum voxel activity) at different time points during or after fractionated radiation therapy (RT) in predicting local failure.

Week*	Volume^†		SUV^†max		RI^†max		SF^†max		Ki^†max
	AUC^‡	𝑃^‡	AUC^‡	𝑃^‡	AUC^‡	𝑃^‡	AUC^‡	𝑃^‡	AUC^‡	𝑃^‡
0	0.54	NS	0.58	NS	0.71	NS	0.71	NS	0.63	NS
1	0.63	NS	0.58	NS	0.92	0.03	0.92	0.03	0.58	NS
2	0.71	NS	0.75	NS	0.92	0.03	0.83	0.09	0.79	NS
3	0.71	NS	0.71	NS	0.67	NS	0.67	NS	0.58	NS
4	0.79	NS	0.58	NS	0.75	NS	1.00	0.01	0.38	NS
5	0.88	0.06	0.79	NS	0.63	NS	0.79	NS	0.79	NS
6	0.83	0.09	0.75	NS	0.75	NS	0.71	NS	0.71	NS
7	0.92	0.03	0.96	0.02	0.50	NS	0.67	NS	0.83	0.09

∗Week: time from the start of radiotherapy (which lasted 5 weeks).
†As denoted in Table 1.
‡AUC: area under the receive operating characteristic (ROC) curve. An AUC of 1 denotes perfect predictive accuracy, an AUC of 0.5 denotes complete lack of predictive accuracy, and an AUC of less than 0.5 denotes that the prediction is opposite from the initial hypothesis. P: assessed using the Wilcoxon test, NS: not significant. Significant values (P < 0.05) are displayed in bold.