Adrenal Stereotactic Body Radiation Therapy: The Effects of a Full and Empty Stomach on Radiation Dose to Organs at Risk

Background: Stereotactic Body Radiation Therapy (SBRT) has been reported to be curative in the treatment of oligometastases to the adrenal glands. However, the adrenals are surrounded by radiation-sensitive organs. We performed an Organ at Risk (OAR) analysis for SBRT to the left adrenal gland based on gastric state. Patients and Methods: Twenty random stomachs were divided into “empty” or “full” groups of 10 each based on size. The PTV dose was 54 Gy/6 fx and D 95 coverage of PTV (CTV) (the dose to 95% of the PTV volume). Results: The gastric OAR dose in the empty group was significantly lower than the full group. The OAR dose to the left kidney in the empty group was significantly higher than in the full group. Conclusion: The smaller the stomach size, the lower the dose to the stomach. It is therefore better to perform SBRT on patients with an empty stomach.