In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: Diffusion - weighted imaging may be useful in predicting the outcomes of the lesions of tacrolimus - induced neurotoxicity .
### Output Text:
Diffusion - weighted imaging may be useful in predicting the outcomes of the lesions of <span class="chemical">tacrolimus</span> - induced neurotoxicity . 