Hyperpolarized-13C MRI has recently enabled imaging of cancer pathophysiology with high spatiotemporal resolution in humans. Quantitative measure of tumor metabolism can be made possible by estimating conversion rate constants (e.g. kPL for pyruvate-to-lactate). We have identified 3 systematic sources affecting kPL estimation that were introduced by MR acquisition and pulse sequences – an RF-spoiling effect, a T2*-weighting factor, and a crusher flow-suppression phenomenon. These sources were investigated using a transgenic cancer model and simulations.