Production of 99mTc-labeled iron oxide aerosols for human lung deposition and clearance studies

Wales, Kim A.; Petrow, H.G.; Yeates, Donovan B.

doi:10.1016/0020-708x(80)90005-8

Cited by 33 publications

(9 citation statements)

References 9 publications

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“…The radiolabeling technique has been described in detail by Wales et al 20 Breathing conditions during aerosol inhalations were controlled, with CF patients targeting a 0.6-L tidal volume (15 breaths/min) and healthy subjects targeting a 0.5-L tidal volume (30 breaths/min). Following this inhalation, subjects were immediately seated in front of the gamma camera.…”

Section: Subjectsmentioning

confidence: 99%

Regional Deposition of Coarse Particles and Ventilation Distribution in Healthy Subjects and Patients with Cystic Fibrosis

Brown¹,

Zeman

Bennett

2001

Journal of Aerosol Medicine

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The efficacy of inhaled pharmaceuticals depends, in part, on their site of respiratory deposition. Markedly nonuniform ventilation distribution may occur in persons with obstructive airways diseases and may affect particle deposition. We studied the relationship between regional deposition (RDep) and regional ventilation (RVent) in a group of 12 cystic fibrosis (CF) patients with mild to moderate airway obstruction (63 +/- 8% predicted FEV1) and 11 healthy nonsmoking volunteers (104 +/- 13% predicted FEV1) using planar scintigraphic methods. RDep was assessed from initial deposition and 24-h retention images for monodisperse technetium-99m-labeled iron oxide particles (5-microm MMAD). Regional volumes and RVent were assessed from xenon-133 equilibrium and washout, respectively. Six regions of interest per lung were established by dividing each lung into thirds by height and approximately half by width. The two lower regions of the left lung were not analyzed due to activity in the stomach. Remaining regions were categorized as central (two interior-most regions) and peripheral (eight exterior regions). RDep and RVent were computed for the eight peripheral regions. Tracheobronchial (TB) deposition was estimated for each of the peripheral regions as the difference between initial activity and decay-corrected 24-h retention or parenchymal deposition. RDep was computed as the fraction of material within a region normalized to regional volume. RVent for each region was determined by normalizing the xenon washout rate for that region by the total washout rate for the eight peripheral regions. Significant linear associations were found between RDep and RVent in both the healthy subjects and CF patients. In healthy subjects, RDep in the TB airways was positively associated with RVent (p = 0.03). In CF patients, RDep in the TB airways was negatively associated with RVent (p = 0.04) and RDep in the parenchyma was positively associated with RVent (p < 0.001). The initial pattern of RDep in the lung was not significantly associated with RVent in either group. These data suggest that significant coarse particle deposition may occur in the TB airways of poorly ventilated lung regions in CF patients, whereas, particle deposition in the TB airways of the healthy subjects follows ventilation.

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Section: Subjectsmentioning

confidence: 99%

Regional Deposition of Coarse Particles and Ventilation Distribution in Healthy Subjects and Patients with Cystic Fibrosis

Brown¹,

Zeman

Bennett

2001

Journal of Aerosol Medicine

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“…The detailed procedures for radiolabeling and producing these aerosols are described by Wales et al (26). Some leaching of radiolabel from the particles has been found over time, but in vitro analysis in simulated body fluids suggests that the leaching rate is reproducible (26).…”

Section: Radiolabeled Aerosol Bolus Inhalationsmentioning

confidence: 99%

Bronchial airway deposition and retention of particles in inhaled boluses: effect of anatomic dead space

Bennett

Scheuch

Zeman

et al. 1998

Journal of Applied Physiology

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The fractional deposition of particles in boluses delivered to shallow lung depths and their subsequent retention in the airways may depend on the relative volume and size of an individual's airways. To evaluate the effect of variable anatomic dead space (ADS) on aerosol bolus delivery we had healthy subjects inhale radiolabeled, monodisperse aerosol (99mTc-iron oxide, 3.5 micron mean mondispersed aerosol diameter) boluses (40 ml) to a volumetric front depth of 70 ml into the lung at a lung volume of 70% total lung capacity end inhalation. By using filter techniques, aerosol photometry, and gamma camera analysis, we estimated the fraction of the inhaled boluses deposited in intrathoracic airways (IDF). ADS by single-breath N2 washout was also measured from 70% total lung capacity. Results showed that among all subjects IDF was variable (range = 0.04-0.43, coefficient of variation = 0.54) and increased with decreasing ADS (r = -0.76, P = 0.001, n = 16). We found significantly greater deposition in the left (L) vs. right (R) lungs; mean L/R (ratio of deposition in L lung to R lung, normalized to ratio of L-to-R lung volume) was 1.58 +/- 0.42 (SD; P < 0.001 for comparison with 1.0). Retention of deposited particles at 2 h was independent of ADS or IDF. There was significant retention of particles at 24 h postdeposition (0.27 +/- 0.05) and slow clearance of these particles continued through 48 h postdeposition. Finally, analysis of central-to-peripheral ratios of initial deposition and 24-h-retention gamma-camera images suggest significant retention of insoluble particles in large bronchial airways at 24 h postdeposition (i.e., 24 h central-to-peripheral ratio = 1.40 +/- 0. 44 and 1.82 +/- 0.54 in the R and L lung, respectively; P < 0.02 for comparison with 1.0). These data may prove useful for 1) designing aerosol delivery techniques to target bronchial airways and 2) understanding airway retention of inhaled particles.

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“…was prepared by the deionization of a ferric nitrate solution, as described by Wales et al (1980). The sol was aerosolized using a Collision compressed-air nebulizer.…”

Section: Exposure Chamber Interior Wall Baffle Square Cross Section Cmentioning

confidence: 99%

Effects of pollutant atmospheres on surface receptors of pulmonary macrophages

Prasad

Rao

Mannix

et al. 1988

Journal of Toxicology and Environmental Health

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Production of 99mTc-labeled iron oxide aerosols for human lung deposition and clearance studies

Cited by 33 publications

References 9 publications

Regional Deposition of Coarse Particles and Ventilation Distribution in Healthy Subjects and Patients with Cystic Fibrosis

Regional Deposition of Coarse Particles and Ventilation Distribution in Healthy Subjects and Patients with Cystic Fibrosis

Bronchial airway deposition and retention of particles in inhaled boluses: effect of anatomic dead space

Effects of pollutant atmospheres on surface receptors of pulmonary macrophages

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