Influence of a vac-fix immobilization device on the accuracy of patient positioning during routine breast radiotherapy

Continued use of basic planning and treatment techniques, in contrast to the improved methods implemented at many other anatomical sites, has emphasized the need for improved breast dosimetry. Any future technique delivering a superior three-dimensional dose distribution will be of maximum benefit if set-up errors are minimized. To determine the influence of vacuum moulded bag (vac-fix) immobilization on routine breast radiotherapy, 17 patients received half their radiotherapy fractions using our standard breast board technique and half using a vac-fix device positioned on the breast board. Treatment accuracy and reproducibility were assessed for each technique using daily electronic portal imaging and were analysed in terms of random and systematic translational and rotational displacements of treatment fields with respect to corresponding simulation images. In addition, patients completed a short questionnaire aimed at determining which technique they preferred. Results showed that random errors for the two techniques did not differ significantly. Approximately 80% of random translations recorded were less than 3 mm and 80% of random rotations were less than 1.5 degrees. Systematic errors showed some improvement with the vac-fix system. In the anteroposterior direction, approximately 80% of systematic errors were less than 4 mm for both techniques, but in the superoinferior direction the 80% point was reduced from 5.0 mm for the standard set-up to 2.7 mm for treatment in vac-fix. For rotational systematic errors, the corresponding value dropped from 1.8 degrees for the standard set-up to 1.1 degrees in vac-fix. Therefore, for many patients, additional use of a vac-fix device improved the transfer of the planned set-up from simulator to treatment unit. Additionally, answers to the questionnaire indicated that patients generally favoured the vac-fix system over use of the breast board alone. In conclusion, however, introduction of vac-fix immobilization for all patients was not thought justified as the improvements demonstrated are not likely to be clinically significant with the present treatment technique.     

Disparities in injury mortality between Uganda and the United States: comparative analysis of a neglected disease

Background  

The burden of global injury-related deaths predominantly affects developing countries, which have little infrastructure to evaluate these disparities. We describe injury-related mortality patterns in Kampala, Uganda and compare them with data from the United States and San Francisco (SF), California.     

Factors influencing unexpected disposition after orthopedic ambulatory surgery

Study ObjectiveTo analyze whether patient characteristics, ambulatory facility type, anesthesia provider and technique, procedure type, and temporal factors impact the outcome of unexpected disposition after ambulatory knee and shoulder surgery.DesignRetrospective analysis of a national database.SettingFreestanding and hospital-based ambulatory surgery facilities.MeasurementsAmbulatory knee and shoulder surgery cases from 1996 and 2006 were identified through the National Survey of Ambulatory Surgery. The incidence of unexpected disposition status was determined and risk factors for such outcome were analyzed.Main ResultsFactors independently increasing the risk for unexpected disposition included procedures performed in hospital-based versus freestanding facilities [odds ratio (OR) 6.83 (95% confidence interval [CI] 4.34; 10.75)], shoulder versus knee procedures [OR 3.84 (CI 2.55; 5.77)], anesthesia provided by nonanesthesiology professionals and certified registered nurse-anesthetists versus anesthesiologists [OR 7.33 (CI 4.18; 12.84) and OR 1.80 (CI 1.09; 2.99), respectively]. Decreased risk for unexpected disposition was for procedures performed in 2006 versus 1996 [OR 0.15 (CI 0.10; 0.24)] and the use of anesthesia other than regional or general [OR 0.34 (CI 0.18; 0.68)].ConclusionsThe decreased risk for unexpected disposition associated with more recent data and with freestanding versus hospital-based facilities may represent improvements in efficiency, while the decreased odds for such disposition status associated with the use of other than general or regional anesthesia may be related to a lower invasiveness of cases. We found an increased risk of adverse disposition in cases where the anesthesia provider was a nonanesthesiology professional. No difference in this outcome was noted when an anesthesia care team provided care.     

Surgery and Anesthesia Capacity-Building in Resource-Poor Settings: Description of an Ongoing Academic Partnership in Uganda

Background

Surgery and perioperative care have been neglected in the arena of global health despite evidence of cost-effectiveness and the growing, substantial burden of surgical conditions. Various approaches to address the surgical disease crisis have been reported. This article describes the strategy of Global Partners in Anesthesia and Surgery (GPAS), an academically based, capacity-building collaboration between North American and Ugandan teaching institutions.

Methods

The collaboration’s projects shift away from the trainee exchange, equipment donation, and clinical service delivery models. Instead, it focuses on three locally identified objectives to improve surgical and perioperative care capacity in Uganda: workforce expansion, research, collaboration.

Results

Recruitment programs from 2007 to 2011 helped increase the number of surgery and anesthesia trainees at Mulago Hospital (Kampala, Uganda) from 20 to 40 and 2 to 19, respectively. All sponsored trainees successfully graduated and remained in the region. Postgraduate academic positions were created and filled to promote workforce retention. A local research agenda was developed, more than 15 collaborative, peer-reviewed papers have been published, and the first competitive research grant for a principal investigator in the Department of Surgery at Mulago was obtained. A local projects coordinator position and an annual conference were created and jointly funded by partnering international efforts to promote collaboration.

Conclusions

Sub-Saharan Africa has profound unmet needs in surgery and perioperative care. This academically based model helped increase recruitment of trainees, expanded local research, and strengthened stakeholder collaboration in Uganda. Further analysis is underway to determine the impact on surgical disease burden and other important outcome measures.     

Treatment accuracy of fractionated stereotactic radiotherapy.

BACKGROUND AND PURPOSE: To assess the geometric accuracy of the delivery of fractionated stereotactic radiotherapy (FSRT) for brain tumours using the Gill-Thomas-Cosman (GTC) relocatable frame. Accuracy of treatment delivery was measured via portal images acquired with an amorphous silicon based electronic portal imager (EPI). Results were used to assess the existing verification process and to review the current margins used for the expansion of clinical target volume (CTV) to planning target volume (PTV). PATIENTS AND METHODS: Patients were immobilized in a GTC frame. Target volume definition was performed on localization CT and MRI scans and a CTV to PTV margin of 5mm (based on initial experience) was introduced in 3D. A Brown-Roberts-Wells (BRW) fiducial system was used for stereotactic coordinate definition. The existing verification process consisted of an intercomparison of the coordinates of the isocentres and anatomy between the localization and verification CT scans. Treatment was delivered with 6 MV photons using four fixed non-coplanar conformal fields using a multi-leaf collimator. Portal imaging verification consisted of the acquisition of orthogonal images centred through the treatment isocentre. Digitally reconstructed radiographs (DRRs) created from the CT localization scans were used as reference images. Semi-automated matching software was used to quantify set up deviations (displacements and rotations) between reference and portal images. RESULTS: One hundred and twenty six anterior and 123 lateral portal images were available for analysis for set up deviations. For displacements, the total errors in the cranial/caudal direction were shown to have the largest SD's of 1.2 mm, while systematic and random errors reached SD's of 1.0 and 0.7 mm, respectively, in the cranial/caudal direction. The corresponding data for rotational errors (the largest deviation was found in the sagittal plane) was 0.7 degrees SD (total error), 0.5 degrees (systematic) and 0.5 degrees (random). The total 3D displacement was 1.8 mm (mean), 0.8 mm (SD) with a range of 0.3-3.9 mm. CONCLUSIONS: Portal imaging has shown that the existing verification and treatment delivery techniques currently in use result in highly reproducible setups. Random and systematic errors in the treatment planning and delivery chain will always occur, but monitoring and minimising them is an essential component of quality control. Portal imaging provides fast and accurate facility for monitoring patients on treatment and the results of this study have shown that a reduction in CTV to PTV margin from 5 to 4 mm (resulting in a considerable increase in the volume of normal tissue sparing) could be made.