updated readme with preprint link

README.md

@@ -24,7 +24,7 @@ The **training set**, which comprises the 477 unlabeled cases plus 50 labeled ca
 Participants can further subdivide this dataset locally into training and validation. The remaining 58 labeled cases building the **preliminary and final testing set** is only 
 accessible for evaluation via submission to the challenge. A couple of years after the challenge is closed, the testing set data is also going to be uploaded to the same location as the training set.
 
-Detailed information about the dataset are provided in the [following paper](https://arxiv.org/abs/2503.19119).
+Detailed information about the dataset are provided in the preprint https://arxiv.org/abs/2503.19119 under revision in Medical Physics.
 
 The challenge website can be found here: https://trackrad2025.grand-challenge.org/trackrad2025/