Use of a dedicated pediatric CT imaging service associated with decreased patient radiation dose.

PURPOSE: The growing use of CT as a diagnostic imaging tool has led to increased concern over radiation dose, particularly in pediatric patients. The ALARA concept has been popularized in dose reduction. ALARA supports the use of low-dose, pediatric-specific protocols. Strict adherence to low-dose protocols can be challenging, particularly in a high-volume radiology department that scans both pediatric and adult patients. The aim of this study was to determine whether the relocation of pediatric radiologic services from a combined high-volume pediatric and adult hospital to a children's hospital improves compliance with adjusted lower CT exposure parameters and thus the estimated effective dose of radiation delivered to pediatric patients. METHODS: A retrospective review of abdominal and pelvic CT console dose and exposure parameter data on 495 patients from a combined pediatric and adult radiology department and subsequently 244 patients from a dedicated pediatric radiology department was performed. The console dose-length product was converted to estimated effective dose. Patients were divided into 1 of 8 weight categories for analysis. RESULTS: A statistically significant decrease in the estimated effective dose for abdominal and pelvic CT studies was observed in all but one of the weight categories at the pediatric radiology department compared with the pediatric and adult radiology department. CONCLUSIONS: Imaging pediatric patients in a dedicated pediatric imaging department with dedicated pediatric CT technologists may result in greater compliance with pediatric protocols and significantly reduced patient dose. Conversely, greater scrutiny of compliance with pediatric dose-adjusted CT protocols may be necessary for departments that scan both children and adults.

Two-dimensional and three-dimensional imaging show ciclesonide has high lung deposition and peripheral distribution: a nonrandomized study in healthy volunteers.

Drug deposition is an important factor that contributes to safety and efficacy outcomes of inhaled steroid therapy. Ciclesonide is a nonhalogenated, inhaled corticosteroid under investigation for the treatment of asthma. Therefore, this study was performed to assess lung deposition of ciclesonide. Technetium-99m (99mTc)-labeled ciclesonide (where the 99mTc-label is physically dissolved in the ciclesonide-hydrofluoroalkane [HFA] solution aerosol) inhaled by healthy volunteers was analyzed by two-dimensional (2-D) and three-dimensional (3-D) imaging to determine lung deposition. Six healthy volunteers inhaled one puff of 40 microg (exactuator, equivalent to 50 microg ex-valve) ciclesonide for 2-D imaging, and two healthy volunteers inhaled 10 puffs of 40 microg ciclesonide for 2-D and 3-D imaging. The ciclesonide aerosol was administered via metered-dose inhaler (MDI) containing HFA-134a as propellant. The ex-actuator mean (+/- standard deviation) deposition of ciclesonide in the lungs was higher (52% +/- 11%) than in the mouth/pharynx (38% +/- 14%). Two-dimensional and 3-D imaging showed that ciclesonide reached all regions of the lung. Mean percent deposition in peripheral regions (47% and 34%) was higher than in lower central regions (17% and 30%), as revealed by 3-D and 2-D imaging, respectively. Inhalation of up to 400 microg of ciclesonide produced no drug-related side effects. In conclusion, ciclesonide administered via metered-dose inhaler using HFA-134a as a propellant provided high lung deposition (>50%), greater distribution throughout peripheral regions of the lungs, and relatively low oropharyngeal deposition.

Influence of particle size and patient dosing technique on lung deposition of HFA-beclomethasone from a metered dose inhaler.

The objective of this study was to determine the lung delivery of HFA-134a-beclomethasone dipropionate (HFA-BDP) from a breath-activated inhaler (QVAR Autohaler) compared with proper and improper press and breathe (QVAR P&B) metered dose inhaler (MDI) technique. The hypothesis was that that the smaller particles of BDP from HFA-BDP would stay suspended longer in the inspiratory air of patients and thus reduce the deleterious effects of inhaler discoordination. The study was an open label, four period, cross-over design. Asthmatic patients (n = 7) with a history of asthma symptoms, an FEV-1 of >70% of predicted normal, and a history of reversibility to a beta-agonist of >or=12% were utilized. BDP was radiolabeled with technetium-99m and delivered from the QVAR Autohaler or QVAR P&B device in patients trained to reproducibly utilize coordinated and discoordinated P&B MDI technique. Patients using Autohaler MDI exhibited 60% lung deposition of BDP. Patients using coordinated technique with the P&B MDI exhibited 59% lung deposition. Patients trained to consistently actuate the P&B MDI before inhaling exhibited 37% lung deposition. Patients trained to consistently actuate the P&B MDI late in the inspiration (i.e., 1.5 sec into a 3-sec inspiration) exhibited 50% lung deposition. In conclusion, the breath-activated Autohaler automatically provided optimal BDP lung deposition of 60%. Patients with good P&B MDI technique also received optimal lung deposition of 59%. The degree of lung deposition was decreased as patients demonstrated poor inhaler technique. However patients with poor technique still received a large lung dose of BDP (i.e., >or=37%) compared with lung deposition values of 4-7% for CFC-BDP MDIs previously published and confirmed in this study.

Lung deposition of hydrofluoroalkane-134a beclomethasone is greater than that of chlorofluorocarbon fluticasone and chlorofluorocarbon beclomethasone : a cross-over study in healthy volunteers.

STUDY OBJECTIVES: To compare the lung deposition of radiolabeled hydrofluoroalkane-134a beclomethasone dipropionate (HFA-BDP) with chlorofluorocarbon fluticasone propionate (CFC-FP) and chlorofluorocarbon beclomethasone (CFC-BDP). DESIGN: Six-day, open-label, nonrandomized, crossover study. SETTING: Clinical research laboratory. PARTICIPANTS: Nine healthy, nonsmoking, adult volunteers. INTERVENTIONS: On each study day, participants inhaled one or two puffs of 99mTc-labeled HFA-BDP, CFC-FP, or CFC-BDP. All products delivered 50 micro g per puff ex-valve. Subjects used a respiratory training and monitoring device to meet predefined, standardized inhalation patterns. Immediately after inhalation of radiolabeled study drug, planar gamma camera images were obtained. MEASUREMENTS AND RESULTS: Radiolabeled HFA-BDP had a higher deposition in the lungs (53% ex-actuator) compared with CFC-FP (12 to 13%) and CFC-BDP (4%). Conversely, CFC-FP and CFC-BDP had a much higher distribution to the oropharynx (72 to 78%, and 82%, respectively) than HFA-BDP (29%). HFA-BDP was deposited evenly throughout the lungs, while CFC-FP and CFC-BDP deposition was primarily in the large central and intermediate airways. Andersen particle size sampling gave mass median aerodynamic diameters for HFA-BDP, CFC-FP, and CFC-BDP of 0.9 micro m, 2.0 micro m, and 3.5 micro m, respectively. CONCLUSIONS: Lung deposition was greater with HFA-BDP compared with CFC-FP and CFC-BDP. Deposition values appeared to be related to the particle size distribution of each inhaler, with the smaller particles of HFA-BDP providing the greatest lung deposition and least oropharyngeal deposition.