PURPOSE In the treatment of uveal melanomas, the optimal prescribed dose to maximize disease control, but minimize radiation-related complications is unknown. Historically our institution has treated uveal melanomas to doses less than 85 Gy to the tumor apex even if the apex was less than 5mm in height. Here, we investigate how tumor control and visual outcomes are affected by the radiation dose at the tumor apex. METHODS AND MATERIALS A retrospective review was performed to evaluate patients treated for uveal melanoma with Iodine-125 plaques between 1988 and 2010. Radiation dose is reported as dose to tumor apex and dose to 5 mm. Primary end points included time to local failure, distant failure, and death. Secondary end points included eye preservation, visual acuity, and radiation-related complications. Univariate and multivariate analyses were performed to determine association between radiation dose and the end point variables. RESULTS One hundred ninety patients with sufficient data to evaluate the end points were included. The 5 year local control (LC) rate was 91%. The 5 year distant metastases (DM) rate was 10%. The 5 year overall survival (OS) rate was 84%. There were no differences in outcome (LC, DM, OS) when dose was stratified by apex dose quartile (<69 Gy, 69–81 Gy, 81–89 Gy, >89 Gy). However, increasing apex dose and dose to 5 mm depth were correlated with greater visual acuity loss (p=0.02, p=0.0006), worse final visual acuity (p=0.02, p<0.0001) and radiation complications (p<0.0001, p=0.0009). In addition, enucleation rates were worse with increasing quartiles of dose to 5 mm (p=0.0001). CONCLUSIONS Doses at least as low as 69 Gy prescribed to the tumor apex achieve rates of local control, distant metastasis free survival, and overall survival that are similar to radiation doses of 85 Gy to the tumor apex, but with improved visual outcomes.

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Purpose To describe renal shielding techniques and dosimetry in delivering total body irradiation (TBI) to patients with severe systemic sclerosis (SSc) enrolled on a hematopoietic stem cell transplant protocol. Methods and Materials The SCOT protocol employs a lymphoablative preparative regime including 800cGy TBI delivered in two 200 cGy fractions twice a day before CD34+ selected autologous hematopoietic stem cell transplantation. Lung and kidney dose is limited to 200 cGy to protect organs damaged by SSc. Kidney block proximity to the spinal cord was investigated and guidelines were developed for acceptable lumbar area TBI dosing. Information on kidney size and the organ shifts from supine to standing positions were recorded using diagnostic ultrasound (US). Minimum distance between the kidney blocks (dkB) and the lumbar spine region dose were recorded and in vivo dosimetry was performed at several locations to determine doses of irradiation delivered. Results Eleven patients were treated at our center with an AP/PA TBI technique. A 10–20% dose inhomogeneity in the lumbar spine region was achieved with a minimum kidney block separation of 4–5 cm. The average lumbar spine dose was 179.6 ± 18.1 cGy, with an average dkB of 5.0 ± 1.0 cm. Kidney block shield design was accomplished using a combination of US and non-contrast CT (computerized tomography) or CT imaging alone. The renal US revealed a wide range of kidney displacement from upright to supine positions. Overall, the average in vivo dose for the kidney prescription point was 193.4 ± 5.1 cGy. Conclusions The dose to the kidneys can be attenuated while maintaining a 10–20% dose inhomogeneity in the lumbar spine area. The kidneys were localized more accurately using both US and CT imaging. With this technique, renal function has been preserved and the study continues to enroll.