In theory, no difference between a voltage source + a big resistor instead of a current source. There is even a way to convert from one to another: Thevenin/Norton equivalence for (Vsource with serial Rs) <===> (Isource with parallel Rp).
In practice, it depends. No component is ideal, so a resistor is expected to have stray capacitance, inductance, temperature coefficient, etc. It depends what parameters matter or not for a given test, and what value ranges are expected for a given test.
The specs for a tunneling microscope amplifier are not common knowledge. Might help answering if you briefly explain what do you want to test for a transimpedance amplifier used in a tunneling microscope. Ranges for current, noise, frequency, temp, specific peculiarities, etc.