Boil pasta in lightly salted water for 10 minutes, or until al dente; drain well.

Preheat oven to 350 degrees F (175 degrees C). Spray a 2 1/2 quart casserole dish with cooking spray.

Mix tuna with cream of mushroom soup, cream of celery soup, milk, salt, black pepper, frozen vegetables, and garlic in a medium saucepan. Place pan over medium low heat, and heat through.

Mix tuna mixture with pasta. Spread 1/2 of the noodles into the prepared dish. Arrange all but 1/4 cup of the cheese over the noodles, then spread the remaining noodle mixture over the cheese. Top with crushed crackers and remaining cheese.

Bake, uncovered, for 20 to 30 minutes; cook until the casserole is hot, and the crackers begin to brown. Let cool for 10 minutes before serving.