Glycogen storage disease type Ia (GSDIa) is caused by an inherited single-gene defect resulting in an impaired glycogen to glucose conversion pathway. Targeted ultrasound mediated delivery (USMD) of plasmid DNA to liver in conjunction with microbubbles may provide a potential treatment for GSDIa patients. As the success of USMD treatmentsis largely dependent on the accessibility of the targeted tissue bythe focused ultrasound beam, this study presents a quantitative approach to determine the acoustically accessible liver volume in GSDIapatients. Models of focused ultrasound beam profiles for transducers of varying aperture and focal lengths were applied to abdomen models reconstructed from suitable CT and MRI images. Transducer manipulations (simulating USMD treatment procedures) were implemented via transducer translations and 2D rotations with the intent of targetingand exposing the entire liver to ultrasound. Results indicate thatacoustically accessible liver volumes can be as large as 60% of theentire liver volume for GSDIa patients and on average 3 times largercompared to a normal group due to GSDIa patients increased liver size. Detailed descriptions of the evaluation algorithm, transducer-and abdomen models will be presented, together with implications forUSMD treatments of GSDIa patients and transducer designs for USMD applications.