Department of Radiologic Sciences Faculty Papers

Retro-Aortic Left Renal Vein

JoAnn Aichroth, RDMS et al. — Tue, 19 Feb 2013 06:50:42 PST

The term retro-aortic left renal vein (RLRV) is defined as the left renal vein coursing posterior to the abdominal aorta. RLRV is an uncommon condition in which the left renal vein passes posterior to the abdominal aorta and anterior to the vertebrae. RLRV may lead to left renal vein hypertension (LRVH) syndrome, which is also known as Nutcracker syndrome. Nutcracker syndrome (NCS) is a condition in which the left renal vein is compressed causing hypertension of the vessel. RLRV and Nutcracker syndrome are vascular anomalies considered to be of clinical importance especially during surgical procedures of the renal vasculature.

Biological impact of geometric uncertainties: what margin is needed for intra-hepatic tumors?

Hsiang-Chi Kuo et al. — Tue, 28 Sep 2010 12:35:50 PDT

BACKGROUND: To evaluate and compare the biological impact on different proposed margin recipes for the same geometric uncertainties for intra-hepatic tumors with different tumor cell types or clinical stages. METHOD: Three different margin recipes based on tumor motion were applied to sixteen IMRT plans with a total of twenty two intra-hepatic tumors. One recipe used the full amplitude of motion measured from patients to generate margins. A second used 70% of the full amplitude of motion, while the third had no margin for motion. The biological effects of geometric uncertainty in these three situations were evaluated with Equivalent Uniform Doses (EUD) for various survival fractions at 2 Gy (SF2). RESULTS: There was no significant difference in the biological impact between the full motion margin and the 70% motion margin. Also, there was no significant difference between different tumor cell types. When the margin for motion was eliminated, the difference of the biological impact was significant among different cell types due to geometric uncertainties. Elimination of the motion margin requires dose escalation to compensate for the biological dose reduction due to the geometric misses during treatment. CONCLUSIONS: Both patient-based margins of full motion and of 70% motion are sufficient to prevent serious dosimetric error. Clinical implementation of margin reduction should consider the tumor sensitivity to radiation.

Sonography of the Neonatal Brain

Traci B. Fox — Tue, 12 Jan 2010 06:55:09 PST

Neurosonography is a critical part of the care of the sick newborn. Sonography is superior to other modalities in imaging of the brain because it can be performed at the bedside, is easily reproducible, and does not require ionizing radiation or sedation. This article refreshes the sonographer in the normal anatomy and appear- ance of the neonatal brain using sonography, as well as some of the more common pathologic conditions that may be encountered.

Multiple Pregnancies: Determining Chorionicity and Amnionicity

Traci B. Fox — Fri, 09 Jun 2006 11:30:28 PDT

The determination of chorionicity and amnionicity in multiple gestations is one that confounds many in the medical field. The importance of diagnosing the type of multiple gestation cannot be overstated. This is intended to be an introductory primer and refresher to chorionicity and amnionicity. We will first examine what determines mono- versus dichorionic twinning including zygosity and cleavage of the zygote.