First Trimester Screening and its Impact on Uptake of Diagnostic Testing

Introduction: First Trimester Screening (FTS) combines maternal age with fetal nuchal translucency (NT) and maternal analytes to identify pregnancies at an increased risk for Down syndrome and trisomy 18. Though the accuracy of this screening is high, it cannot replace the conclusive accuracy of prenatal diagnostic testing (PDT). Since FTS has been available, a decrease in the number of women who pursue PDT has been observed. This study sought to determine if there has been a significant change in the amount of PDT performed in our clinics, if the type of FTS result affects the patient’s decision regarding PDT, and what the patient’s intentions are regarding PDT. Material and Methods: A database review was performed for the two years prior and the two years after the January 2007 American College of Obstetricians and Gynecologists (ACOG) guidelines regarding FTS were issued. We compared the number of women who were AMA and the number of women who were AMA and had PDT between those time periods. We also determined the number of positive and negative FTS results, and determined how many of those patients had PDT. Finally, we surveyed our patients and referring physicians to determine: what the patient understands about FTS, what the patient’s intentions are regarding FTS, and how physicians present the option of FTS to their patients. Results: We determined that there was a 19.6% decrease in the amount of PDT performed when we compared the two time periods at our three specified clinics. Many of our patients were against having PDT prior to their genetic counseling session, but after they received genetic counseling, 76% of our population became open to the possibility of having PDT. Conclusion: Similar to previous studies, we determined that there has been a significant decrease in the number of PDT procedures performed at our clinics, which coincides with the release of the January 2007 ACOG statement regarding FTS. While our patients regarded FTS as a way to gain early information about their pregnancy in a non-invasive manner, they also stated they would use their results as a way to aid in their decision regarding PDT.

The Development and Implementation of an Anthropomorphic Head Phantom for the Assessment of Proton Therapy Treatment Procedures

Proton therapy has become an increasingly more common method of radiation therapy, with the dose sparing to distal tissue making it an appealing option, particularly for treatment of brain tumors. This study sought to develop a head phantom for the Radiological Physics Center (RPC), the first to be used for credentialing of institutions wishing to participate in clinical trials involving brain tumor treatment of proton therapy. It was hypothesized that a head phantom could be created for the evaluation of proton therapy treatment procedures (treatment simulation, planning, and delivery) to assure agreement between the measured dose and calculated dose within ±5%/3mm with a reproducibility of ±3%. The relative stopping power (RSP) and Hounsfield Units (HU) were measured for potential phantom materials and a human skull was cast in tissue-equivalent Alderson material (RLSP 1.00, HU 16) with anatomical airways and a cylindrical hole for imaging and dosimetry inserts drilled into the phantom material. Two treatment plans, proton passive scattering and proton spot scanning, were created. Thermoluminescent dosimeters (TLDs) and film were loaded into the phantom dosimetry insert. Each treatment plan was delivered three separate times. Each treatment plan passed our 5%/3mm criteria, with a reproducibility of ±3%. The hypothesis was accepted and the phantom was found to be suitable for remote audits of proton therapy treatment facilities.