How to Loop NSThread?

I am curious to know if you can loop an NSThread for the iphone sdk. I have learned that instead of using NSTime开发者_JS百科rs which do run off of the main UI, I can use NSThreads to run actions in the background. Most of my NSTimers have the "repeats:" to YES, thus I need to know if NSThreads can be looped.

Thanks Kevin

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- (void) loop {
    while (!finished) { … };
}

- (void) startThreadedLoop {
    finished = NO;
    [self performSelectorInBackground:@selector(loop)];
}