ABSTRACT
Background: the dynamic phantom is one of the best tools to study the impact of motion on tumor target delineation and absorbed dose verification during dose delivery
Materials and Methods: this study, a 6-DOF [degrees of freedom] phantom was designed following the stacked serial kinematics and assembled by six commercial motion stages to generate 6-DOF motion, which were RotX [pitch, around X], RotY [roll, around Y], TransZ [anterior-posterior], RotZ [yaw, around Z], TransY [superior-inferior] and TransX [left-right]. Tumor targets were designed by six plastic spheres for the delineation test. Also, an ionization chamber array detector and RW3 solid water were combined to measure the absorbed dose for dose verification tests
Results: the maximum translation speeds for LineX and LineY were 50mm/s and 35mm/s for LineZ, while the maximum rotation speeds for RotX, RotY, RotZ were 5.33° per second, 6degree per second and 15degree per second respectively. Spiral-CT and 4D-CT images acquired in the static and dynamic states successfully showed the influences of tumor motion on target delineation. In the absorbed dose verification, all cases did not pass the gamma test; the pass rate for the 6-DOF motion case was only 34.2% and the pass rates of all other cases were less than 90%
Conclusion: the phantom designed in this study is able to simulate complex tumor motion and can be used to study the influence of tumor motion in radiotherapy
ABSTRACT
<p><b>INTRODUCTION</b>Hand infections in patients with end-stage renal failure (ESRF) are more diffi cult to treat and have had the worse outcomes. This paper examines the epidemiology, bacteriology and outcomes of surgically managed upper limb infections in these vulnerable patients.</p><p><b>MATERIALS AND METHODS</b>All patients from a single centre with surgically-managed upper limb infections between 2001 and 2007 were reviewed. We collected epidemiological data on demographics, type and site of infection, bacteriology, surgical treatment, complications and mortality.</p><p><b>RESULTS</b>Forty-seven out of 803 (6%) patients with surgically managed upper limb infections in the study period had ESRF. The average age was 59 years. ESRF was secondary to diabetes in 88% of cases. Patients presented on average 7 days after onset of symptoms. Abscesses (34%), wet gangrene (26%) and osteomyelitis (11%) were the commonest infections. Methicillin-resistant Staphylococcus aureus (MRSA) was the commonest pathogen (29%), occurring either in isolation or with other organisms. Eighteen percent of single organisms cultured were gram-negative. Multiple organisms occurred in 29%. A median of 2 operations were required. Thirty-six percent of all cases required amputation. Twenty-fi ve percent of patients had a life-threatening event (myocardial infarction or septic shock) during treatment.</p><p><b>CONCLUSIONS</b>ESRF patients present late with severe upper limb infections. Nosocomial infections are common. Initial empirical antibiotic treatment should cover MRSA and gram-negative bacteria. Immediate referral to a hand surgery unit is recommended. Multi-disciplinary management of the patient with input from physicians and anaesthetists or intensivists in the perioperative period is necessary to optimise the patient for surgery and to manage active medical comorbidities and complications after surgery.</p>