Fluoroscopic sentinel events in neuroendovascular procedures: how to screen, prevent, and address occurrence.

Radiation-induced skin injury during fluoroscopic procedures has been recently addressed by The Joint Commission, which defined prolonged fluoroscopy resulting in a cumulative peak skin dose of ≥15 Gy to a single field as a sentinel event (FSE). Neuroendovascular procedures can be associated with a high radiation skin dose and present risks such as potential FSEs. Managing these risks is the responsibility of the interventional neuroradiologist. In this review, we discuss hospital policies needed for screening and preventing FSEs, methods for minimizing radiation-induced skin injury, and actions necessary to address potential FSEs once they have occurred.

SU-E-I-10: Putting Teeth into Your CT Dosimetry Program: Approaches to Cone- Beam Dental/Maxillofacial CT Dosimetry.

PURPOSE: To review and compare different approaches to the problem of dosimetry for limited field-of-view (FOV) cone beam CT devices for dental and maxillofacial applications. METHODS: The determination of patient doses from specialized, cone-beam CT devices for dental and maxillofacial work requires medical physicists to re-evaluate their dosimetry methods. These devices work in cone-beam geometry, with an axial field dimension on the order of the lengths of the standard head CTDI phantom and pencil ionization chamber. They may also utilize less than 360 degree scans, resulting in asymmetrical radiation distributions. This operating regime is far from that for which conventional CT dosimetry was designed, and alternative approaches must be considered. The alternatives include extensions of conventional CT dosimetry currently used for large axial FOV scanners (e.g. the extended CTDI parameter (CTDIe) for the Toshiba Aquillion One with 160 mm axial FOV) and the new method based on point dosimetry measurements recently formalized in AAPM Report TG-111. Conventional, modified-conventional, and TG-111 dosimetry measurements are used in two CT dose phantoms (adult head and pediatric head) to obtain dose indices for the Planmeca ProMax 3D Max dental CT scanner. Surface dose maps are generated using radiochromic film for correlation with the chamber dosimetry. RESULTS: Results for the three dosimetry approaches are compared for the specific case of the ProMax 3D Max scanner. Strengths and weaknesses of the three measurement paradigms for this type of application are compared. CONCLUSIONS: The increasing availability of specialized scanners operating in full cone-beam mode will require the clinical medical physicist to be conversant with extensions to the CT dose index methodology suitable for this equipment.

SU-E-I-57: CT Dose Metrics: What Are We Tracking.

PURPOSE: Recent guidance by The Joint Commission and CRCPD recommendations require establishing CT reference dose levels (RDLs) for clinical protocols and recording CT dose metrics in the patient's medical record. This presentation addresses which dose values in the CT report should be recorded for the purposes of monitoring patient dose and determining RDLs effectively. METHODS: CT dose reports are commonly recorded in the PACS as screen captures, although structured reporting is becoming available on current CT scanners and PACS systems. The goal is to obtain data that correctly reflects the patient's dose, but the dose information captured is not standardized across vendors and can be difficult to compare. Multi-phase studies, deviations from established protocols and dynamic scanning present problems when recording numbers to establish RDLs because of the lack of information on the anatomy scanned. The cumulative DLP and CTDIvol manually entered by radiologic technologists into the electronic medical record were compared with more detailed dose metrics compiled from PACS images. RESULTS: Analysis of this data showed that simple cumulative metrics are a poor indicator of patient dose. Major problems are 1) the inclusion of dynamic scan doses associated with bolus tracking, which can skew protocol CTDIvol values by a factor of up to 20, and 2) add-on scans of non-overlapping anatomy which can inaccurately increase apparent patient dose. CONCLUSIONS: Recording CTDIvol to monitor patient doses is not straightforward, since details of the actual anatomy scanned are lacking without image-based review. More granular dose reporting which identifies individual acquisitions is required; however, current RIS systems do not provide the flexibility necessary to capture all this information.

Measurement of group delay dispersion of high numerical aperture objective lenses using two-photon excited fluorescence.

We determined the group-delay dispersion (GDD) of five microscope objectives by measuring the second-order autocorrelation at the focal points of the objectives with two-photon excited fluorescence as the power square sensor. We found that typical microscope lens systems introduce significant GDD (2000-6500 fs(2)). The third-order dispersion determined for these objectives limits the minimum obtainable pulse width at the focal point of an objective to 20-30 fs if not compensated. No significant chromatic aberration or higher-order dispersion effects were found for any of the optical components measured within the wavelength range of 700-780 nm and for pulse widths greater than 50-60 fs.

Standardized classroom management program: Social validation and replication studies in Utah and Oregon.

A comprehensive validation study was conducted of the Program for Academic Survival Skills (PASS), a consultant-based, teacher-mediated program for student classroom behavior. The study addressed questions related to: (a) brief consultant training, (b) subsequent teacher training by consultants using PASS manuals, (c) contrasts between PASS experimental teachers and students and equivalent controls on measures of teacher management skills, student classroom behavior, teacher ratings of student problem behaviors, and academic achievement, (d) reported satisfaction of participants, and (e) replication of effects across two separate school sites. Results indicated that in both sites significant effects were noted in favor of the PASS experimental group for (a) teacher approval, (b) student appropriate classroom behavior, and (c) four categories of student inappropriate behavior. Program satisfaction ratings of students, teachers, and consultants were uniformly positive, and continued use of the program was reported a year later. Discussion focused upon issues of cost-effectiveness, differential site effects, and the relationship between appropriate classroom behavior and academic achievement.

Group contingencies for group consequences in classroom management: a further analysis.

The relative effects of rules, rules + feedback, and rules + feedback + group and individual consequences for appropriate behavior were investigated in three elementary classrooms during reading and mathematics periods. The consequences were individual and group praise, and group activities. The total intervention package (rules + feedback + group and individual consequences) was most effective in increasing appropriate behavior. Rules + feedback produced increased appropriate behavior in two of the three classrooms. Rules alone produced no change in classroom behavior. Maintenance of appropriate classroom behavior was noted approximately three weeks after the program ended. Teacher's correct use of praise was also maintained for two of the three teachers at levels generated during the total package condition.