Cumulative radiation dose after lung transplantation in patients with cystic fibrosis.

PURPOSE: The purpose of this study was first to evaluate the imaging-related cumulative post-transplantation radiation dose in cystic fibrosis (CF) lung transplantation (LT) recipients and second, to identify the occurrence and type of malignancies observed after LT. MATERIALS AND METHODS: A total of 52 patients with CF who underwent LT at our institution between January 2001 and December 2006 with at least 3 years of survival were retrospectively included. There were 27 men and 25 women with a mean age of 24.4±9.2 (SD) years (range: 7.6-52.9 years) at the time of LT. Calculation of cumulative effective and organ doses after LT were based on dosimetry information and acquisition parameters of each examination. Cumulative radiation doses were calculated until June 2016, but stopped at the time of de novomalignancy diagnosis, for patients developing the condition. RESULTS: Patients received a mean cumulative effective dose of 110.0±51.6 (SD) mSv (range: 13-261.3 mSv) over a mean follow-up of 8.1±3.6 (SD) years (range: 0.5-13.5 years), with more than 100mSv in 5 years in 19/52 patients (37%). Chest CT accounted for 73% of the cumulative effective dose. Mean doses to the lung, breast and thyroid were 152.8±61.1 (SD) mGy (range: 21.2-331.6 mGy), 106.5±43.2 (SD) mGy (range: 11.9-221.4 mGy) and 72.7±31.8 (SD) mGy (range: 9.5-165.0 mGy), respectively. Nine out of 52 patients (17%) developed a total of 10 de novo malignancies, all but one attributable to immunosuppression after a mean post-transplantation follow-up period of 11.1±3.5 (SD) years (range: 3.7-16.3 years). Six-month cumulative effective dose was not greater in patients with de novomalignancies than in those without de novomalignancies (28.9±14.5 (SD) mGy (range: 13.0-53.4) vs 25.6±15.3 (range: 5.0-69.7), respectively, P>0.05). CONCLUSION: The cumulative effective dose exceeded 100 mSv in 5 years in 37% of LT recipients, the reason why continuous efforts should be made to optimize chest CT acquisitions accounting for 73% of the radiation dose.

Comparison of Two Endovascular Steerable Robotic Catheters for Percutaneous Robot-Assisted Fibroid Embolization.

PURPOSE: To compare outcomes of percutaneous robot-assisted uterine fibroid embolization (UFE) using two different endovascular robotic catheters. METHODS: Twenty-one patients with a symptomatic uterine fibroid were prospectively enrolled in a single-center study to be treated with a percutaneous robot-assisted embolization using the Magellan system. Fourteen patients were treated using a first generation steerable robotic catheter, version 1.0 (group 1), and seven were treated using the new version 1.1 (group 2). Demographic, pathologic, and procedural variables were recorded. Dose Area Product (DAP) and physician equivalent doses were registered for each procedure. Procedural related complications and clinical midterm outcomes were also evaluated. RESULTS: Successful robot-assisted UFE was obtained in eight patients (57.1%) in group 1 and 7 patients (100%) in group 2 (p = 0.01). A successful robot-assisted catheterization of the internal iliac artery anterior branch was performed in all patients of both groups. Median selective target vessel catheterization time was 21.0 ± 12.8 vs 13.4 ± 7 min (p = 0.04) and total fluoroscopy time was 30.3 ± 11.2 vs 19.3 ± 5.9 min, respectively, in group 1 and 2. Mean DAP decreased from 18472.6 ± 15622 to 5469.1 ± 4461.0 cGy·cm2 (p = 0.04). All patients obtained a symptoms relief at 6 months follow-up. CONCLUSIONS: Robot-assisted uterine fibroid embolization is safe and effective. New version of steerable robotic catheter allows performing a faster procedure without related adverse events compared to old version.

Semi-automatic delineation using weighted CT-MRI registered images for radiotherapy of nasopharyngeal cancer.

PURPOSE: To develop a delineation tool that refines physician-drawn contours of the gross tumor volume (GTV) in nasopharynx cancer, using combined pixel value information from x-ray computed tomography (CT) and magnetic resonance imaging (MRI) during delineation. METHODS: Operator-guided delineation assisted by a so-called "snake" algorithm was applied on weighted CT-MRI registered images. The physician delineates a rough tumor contour that is continuously adjusted by the snake algorithm using the underlying image characteristics. The algorithm was evaluated on five nasopharyngeal cancer patients. Different linear weightings CT and MRI were tested as input for the snake algorithm and compared according to contrast and tumor to noise ratio (TNR). The semi-automatic delineation was compared with manual contouring by seven experienced radiation oncologists. RESULTS: A good compromise for TNR and contrast was obtained by weighing CT twice as strong as MRI. The new algorithm did not notably reduce interobserver variability, it did however, reduce the average delineation time by 6 min per case. CONCLUSIONS: The authors developed a user-driven tool for delineation and correction based a snake algorithm and registered weighted CT image and MRI. The algorithm adds morphological information from CT during the delineation on MRI and accelerates the delineation task.