A Comparison of Image Quality and Radiation Exposure Between the Mini C-Arm and the Standard C-Arm.

Background: The use of intraoperative fluoroscopy has become mandatory in osseous hand surgery. Due to its overall practicality, the mini C-arm has gained popularity among hand surgeons over the standard C-arm. This study compares image quality and radiation exposure for patient and staff between the mini C-arm and the standard C-arm, both with flat panel technology. Methods: An observer-based subjective image quality study was performed using a contrast detail (CD) phantom. Five independent observers were asked to determine the smallest circles discernable to them. The results were plotted in a graph, forming a CD curve. From each curve, an image quality figure (IQF) was derived. A lower IQF equates to a better image quality. The patients' entrance skin dose was measured, and to obtain more information about the staff exposure dose, a perspex hand phantom was used. The scatter radiation was measured at various distances and angles relative to a central point on the detector. Results: The IQF was significantly lower for the mini C-arm resulting in a better image quality. The patients' entrance dose was 10 times higher for the mini C-arm as compared with the standard C-arm, and the scatter radiation threefold. Conclusions: Due to its improved image quality and overall practicality, the mini C-arm is recommended for hand surgical procedures. To ensure that the surgeons' radiation exposure is not exceeding the safety limits, monitoring radiation exposure using mini C-arms with flat panel technology during surgery should be done in a future clinical study.

Radiation Exposure to Surgeon and Assistant During Flat Panel Mini C-Arm Fluoroscopy in Hand and Wrist Surgical Procedures.

PURPOSE: During mini C-arm fluoroscopy, both the patient and surgical team are exposed to scatter radiation. The objective of this study was to quantify body, thyroid, and hand radiation exposure to surgeon and assistant during intraoperative use of flat panel mini C-arm fluoroscopy in hand and wrist surgical procedures. METHODS: Over 5 months, the surgeon's and assistant's radiation exposure was recorded during all osseous hand and wrist surgical procedures. Whole-body and thyroid radiation exposure were measured with 2 types of dosimeters: a photon thermoluminescence detector and a RaySafe i2 real-time dosimeter. Ring dosimeters were used to quantify hand radiation exposure. RESULTS: Mini C-arm fluoroscopy was used in 94 surgical procedures. Total fluoroscopy time was 1,996 seconds and varied between surgical procedures (range, 1-152 seconds; median, 11 seconds). No thermoluminescence detector photon dosimeter exceeded the threshold limit of 0.1 mSv. The RaySafe i2 real-time dosimeters recorded a cumulated dose of 0.029 mSv for the body and 0.012 mSv for the thyroid position of the surgeon. The assistant received a cumulated dose of 0.011 mSv for the body and 0.011 mSv for the thyroid position. The ring dosimeters showed a cumulated dosage of 1.28 mSv for the surgeon and 0.20 mSv for the assistant. CONCLUSIONS: Our results show that the surgeon's and assistant's body, thyroid, and hands were exposed to acceptable levels of scatter radiation during intraoperative use of the flat panel mini C-arm. The surgeon received the highest radiation exposure: 2.9% of the yearly radiation limits for the body, 0.05% for the thyroid position, and 2.56% for the hands. The assistant was exposed to less scatter radiation: 1.1% for the body, 0.04% for the thyroid, and 0.4% for the hands. CLINICAL RELEVANCE: This study quantified radiation levels to which surgeon and assistant are exposed during mini C-arm fluoroscopy in hand and wrist surgical procedures.

[Digital necrosis after local anaesthesia with epinephrine]. / Vingertopnecrose na lokale anesthesie met adrenaline.

BACKGROUND: To date, there is a lack of consensus concerning the application of local anaesthetics with epinephrine in fingers, due to the alleged risk of ischaemic complications. CASE DESCRIPTION: We present the case of a 70-year old woman, with a medical history of diabetes mellitus and an ischemic cerebral infarct, who underwent operative trigger finger release under local anaesthetics with 1% lidocaine-epinephrine (1:100,000) solution. A few hours later, she developed persisting numbness and ischemic symptoms of the digits. Initial antithrombotic treatment with nadroparin did not resolve the issue, but vasodilatory treatment with nifedipine improved symptoms. Nevertheless, digital necrosis developed in the affected fingers several weeks later. Post-operatively, severe atherosclerosis was diagnosed in the affected hand. CONCLUSION: The use of local anaesthesia in conjunction with epinephrine for surgery on digits does offer advantages, but caution is warranted for patients with risk factors predisposing for local circulatory insufficiency. Timely vasodilatory treatment with phentolamine is the preferred option for patients who develop acute ischaemia following local anaesthesia with epinephrine.

Molecular imaging of bone marrow mononuclear cell survival and homing in murine peripheral artery disease.

OBJECTIVES: This study aims to provide insight into cellular kinetics using molecular imaging after different transplantation methods of bone marrow-derived mononuclear cells (MNCs) in a mouse model of peripheral artery disease (PAD). BACKGROUND: MNC therapy is a promising treatment for PAD. Although clinical translation has already been established, there is a lack of knowledge about cell behavior after transplantation and about the mechanism whereby MNC therapy might ameliorate complaints of PAD. METHODS: MNCs were isolated from F6 transgenic mice (FVB background) that express firefly luciferase (Fluc) and green fluorescence protein (GFP). Male FVB and C57Bl6 mice (n = 50) underwent femoral artery ligation and were randomized into 4 groups receiving the following: 1) single intramuscular (IM) injection of 2 × 10(6) MNCs; 2) 4 weekly IM injections of 5 × 10(5) MNCs; 3) 2 × 10(6) MNCs intravenously; and 4) phosphate-buffered saline as control. Cells were characterized by flow cytometry and in vitro bioluminescence imaging (BLI). Cell survival, proliferation, and migration were monitored by in vivo BLI, which was validated by ex vivo BLI, post-mortem immunohistochemistry, and flow cytometry. Paw perfusion and neovascularization was measured with laser Doppler perfusion imaging (LDPI) and histology, respectively. RESULTS: In vivo BLI revealed near-complete donor cell death 4 weeks after IM transplantation. After intravenous transplantation, BLI revealed that cells migrated to the injured area in the limb, as well as to the liver, spleen, and bone marrow. Ex vivo BLI showed presence of MNCs in the scar tissue and adductor muscle. However, no significant effects on neovascularization were observed, as monitored by LDPI and histology. CONCLUSIONS: This is one of the first studies to assess kinetics of transplanted MNCs in PAD using in vivo molecular imaging. MNC survival is short-lived, MNCs do not preferentially home to injured areas, and MNCs do not significantly stimulate perfusion in this particular model.

In vivo bioluminescence for tracking cell fate and function.

Tracking the fate and function of cells in vivo is paramount for the development of rational therapies for cardiac injury. Bioluminescence imaging (BLI) provides a means for monitoring physiological processes in real time, ranging from cell survival to gene expression to complex molecular processes. In mice and rats, BLI provides unmatched sensitivity because of the absence of endogenous luciferase expression in mammalian cells and the low background luminescence emanating from animals. In the field of stem cell therapy, BLI provides an unprecedented means to monitor the biology of these cells in vivo, giving researchers a greater understanding of their survival, migration, immunogenicity, and potential tumorigenicity in a living animal. In addition to longitudinal monitoring of cell survival, BLI is a useful tool for semiquantitative measurements of gene expression in vivo, allowing a better optimization of drug and gene therapies. Overall, this technology not only enables rapid, reproducible, and quantitative monitoring of physiological processes in vivo but also can measure the influences of therapeutic interventions on the outcome of cardiac injuries.