Replacing Tokenized String Using Regular Expression In .NET

using System;
using System.Collections.Generic;
using System.Text.RegularExpressions;

class Program
{
    static void Main(string[] args)
    {
        string text = "Contact name:$NAME$, address:$ADDRESS$, phone:$PHONE$, email:$EMAIL$...";
        Dictionary<string, string> tokenDictionaries = new Dictionary<string, string>();
        tokenDictionaries.Add("NAME", "Rob");
        tokenDictionaries.Add("PHONE", "123456789");
        tokenDictionaries.Add("EMAIL", "Rob@abc.com");
        Console.WriteLine(ReplaceToken(text, tokenDictionaries));
        Console.Read();
    }

    public static string ReplaceToken(string text, Dictionary<string, string> tokenDictionaries)
    {
        string pattern = @"\$.*?\$";
        Match mc = Regex.Match(text, pattern);
        if (mc.Success)
        {
            while (mc.Success)
            {
                if (!string.IsNullOrEmpty(mc.Value))
                {
                    string tokenName = mc.Value.Substring(1, mc.Length - 2);
                    string tokenValue = string.Empty;
                    if (!string.IsNullOrEmpty(tokenName) && tokenDictionaries.ContainsKey(tokenName))
                        tokenValue = tokenDictionaries[tokenName];
                    text = text.Substring(0, mc.Index) + tokenValue + text.Substring(mc.Index + mc.Length);
                    mc = Regex.Match(text, pattern);
                }
            }
        }
        return text;
    }
}

Result:

Contact name:Rob, address:, phone:123456789, email:Rob@abc.com...