This project aims to minimize the B1+ field inhomogeneities that arise when using a flexible transmit coil system in multi-organ hyperpolarized 13C MRI. A method for rapid B1+ measurement of several locations immediately prior to image acquisition was developed to determine scaling factors for the power input of slices over a large field-of-view. These scaling factors ensure that the desired flip angle is achieved across multiple organs. The rapid B1+ measurement technique has been tested in in vivo scans, giving values accurate within ±1μT. This method will be used to minimize the variability in multi-organ thoracic and abdominal imaging.