Standardization of techniques for using planar (2D) imaging for aerosol deposition assessment of orally inhaled products

Stephen Newman, William D. Bennett, Martyn Biddiscombe, Sunalene G. Devadason, Myrna B. Dolovich, John Fleming, Sabine Haeussermann, Claudius Kietzig, Philip J. Kuehl, Beth L. Laube, Knut Sommerer, Glyn Taylor, Omar S. Usmani, Kirby L. Zeman

Research output: Contribution to journalArticlepeer-review


Two-dimensional (2D or planar) imaging with 99mTc radiolabels enables quantification of whole-lung and regional lung depositions for orally inhaled drug products. This article recommends standardized methodology for 2D imaging studies. Simultaneous anterior and posterior imaging with a dual-headed gamma camera is preferred, but imaging with a single-headed gamma camera is also acceptable. Correction of raw data for the effects of gamma ray attenuation is considered essential for accurate quantification, for instance, using transmission scanning with a flood-field source of 99mTc or 57Co. Evidence should be provided of the accuracy of the quantification method, for instance, by determining "mass balance." Lung deposition may be expressed as a percentage of ex-valve or ex-device dose, but should also be given as mass of drug when possible. Assessment of regional lung deposition requires delineation of the lung borders, using X-ray computed tomography, radioactive gas scans (133Xe or 81mKr), or transmission scans. When quantifying regional lung deposition, the lung should be divided into outer (O) and inner (I) zones. A penetration index should be calculated, as the O/I ratio for aerosol, normalized to that for a radioactive gas or transmission scan. A variety of methods can be used to assess lung deposition and distribution. Methodology and results should be documented in detail, so that data from different centers may be compared. The use of appropriate methodology will provide greater confidence in the results of 2D imaging studies, and should allay concerns that such studies are qualitative or semiquantitative in nature.

Original languageEnglish (US)
Pages (from-to)S10-S28
JournalJournal of aerosol medicine and pulmonary drug delivery
Issue numberSUPPL.1
StatePublished - Dec 1 2012


  • gamma scintigraphy
  • lung deposition
  • orally inhaled products
  • planar imaging

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine
  • Pharmaceutical Science
  • Pharmacology (medical)


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