Calling a method in a class running on a separate thread from the main thread

internal class SystemEventsHook : ISystemEventsPlugin
{
    private BigBoxViewController BigBoxViewController;

    [STAThread]
    public void OnEventRaised(string eventType)
    {
        switch (eventType)
        {
            case SystemEventTypes.PluginInitialized:
                Initialization.InitialiseGearbox();
                break;

            case SystemEventTypes.BigBoxStartupCompleted:

                Thread bigBoxThread = new Thread(new ThreadStart(() =>
                {
                    BigBoxViewController = new BigBoxViewController(this);
                    BigBoxViewController.OnBigBoxStartupCompleted();
                    System.Windows.Threading.Dispatcher.Run();
                    
                }));
                bigBoxThread.SetApartmentState(ApartmentState.STA);
                bigBoxThread.IsBackground = true;
                bigBoxThread.Name = "BigBoxViewController";
                bigBoxThread.Start();
                break;
        }

        if (BigBoxViewController != null)
        {
            BigBoxViewController.ProcessSystemEvent(eventType);
        }
    }
}