Help with UDim!!!?

IS there a way to make a frame / image label scale using Udim by using scale and not offset? This is script I am using. It doesn't work unless scale for x and y is 0.

local PositionX = script.Parent.Position.X.Offset
local initX = script.Parent.Size.X.Offset
local p = script.Parent.Parent.Parent.Parent.Parent.Parent.Parent
while true do 
wait()
local PlayerHealth = p.Character.Humanoid.Health 
local PlayerMaxHealth = p.Character.Humanoid.MaxHealth
local Pie = (PlayerHealth / PlayerMaxHealth) --Missed Scale 
--script.Parent.Size = UDim2.new( 0, initX*Pie, 0, 20) 
script.Parent:TweenSize(UDim2.new(0, initX*Pie, 0, 20),"Out","Sine",0.25)
end