You can read the TIF image into an AWT image using Java Advanced Imaging (JAI) API and then convert the AWT image to a JavaFX image using the JavaFX 2.2 SwingFXUtils.toFXImage() method or (if you don't want to use any AWT code) you can write your own TIF image decoder and write the decoder output directly to a JavaFX 2.2 WritableImage.
http://www.rgagnon.com/javadetails/java-0605.html "Display a TIF" (using JAI + AWT).
There used to be somewhere on the JAI page a link to the JAI Image I/O tools which was a subset of JAI and a separate download that you could add to your classpath and that automatically added new files formats supports into ImageIO. Thus no single line of JAI coding was required at all, you could just simply use the regular ImageIO methods.
Since the JAI project has moved out of Sun's to java.net limbo, I am not sure were the download went but should be around here http://java.net/projects/jai-imageio/