Table 3. Representative result of confusion matrix between true labels and predicted labels by DCNN with transfer learning.

		Predicted label
		Benign nodule	Primary lung caner	Metastatic lung cancer
True label	Benign nodule	22	8	5
	Primary lung caner	6	46	8
	Metastatic lung cancer	5	4	19

Because splitting of the training and validation sets was random each time, the ratio between the 3 classes was variable. This confusion matrix corresponds to the results of Fig 4. Abbreviations: DCNN, deep convolutional neural network.