age 18 and older

biopsy-proven malignancy

the diagnosis of hepatocellular carcinoma may be made on a clinical basis without the need for a biopsy if the following criteria are met: a) documentation of hepatitis b or c infection b)liver mass with characteristic imaging (ct or mri) features of hepatocellular carcinoma c) alpha-feta protein (afp) level greater than 20 ng/ml 3. planned curative external beam rt as part of the patients treatment for the cancer diagnosis.

subject must be cable of giving informed consent for standard external beam radiation therapy as well as for the study.

subjects must be able to tolerate the deep inspiration breath hold (dibh) training and procedures.

subjects unsuitable for or unable to undergo definitive external beam, radiation therapy for their diagnosis of cancer

subjects undergoing radiation with palliative (i.e., non-curative) intent.

subjects unwilling to undergo simulation with the spirodynrx (sdx) system.

subjects unable to hold their breath for a minimum of 10 seconds.