Impaired permeability in radiation-induced lung injury detected by technetium-99m-DTPA lung clearance
- Brookhaven National Lab., Upton, NY (United States)
This study evaluates the use of the {sup 99m}Tc-DTPA aerosol lung clearance method to investigate radiation-induced lung changes in eight patients undergoing radiotherapy for lung or breast carcinoma. The sensitivity of the method was compared with chest radiography for detecting radiation-induced changes in the lung, regional alterations within and outside the treatment ports, effect of irradiated lung volume, and dependence on time after radiotherapy. Serial DTPA lung clearance studies were performed before the first radiation treatment (baseline), then weekly during a 5- to 7-wk course, and up to 12 times post-therapy over periods of 56-574 days. The total activity deposited in the lungs for each study was {approx}150 {mu}Ci ({approx}5.6 MBq). DTPA clearance, expressed in terms of the biological half-time, t{sub 1/2}, was computed from the slopes of the least-squares fit regression lines of the time-activity curves for the first 10 min for irradiated and shielded lung regions. Major findings include: (a) significant and early DTPA t{sub 1/2} changes were observed in all patients during and after radiotherapy; (b) changes in DTPA t{sub 1/2} values were observed in both irradiated and shielded lung regions in all patients suggesting a radiation-induced systemic reaction; (c) changes in DTPA t{sub 1/2} values were correlated (p < 0.05) with the irradiated lung volumes; (d) significantly reduced DTPA t{sub 1/2} values were observed in three patients who subsequently presented with clinical symptoms and/or radiographic changes consistent with radiation pneumonitis (t{sub 1/2} fell to 19% {+-} 6% of baseline values, compared with 64% {+-} 17% in the remaining patients [p < 0.01]); (e) the onset of decreased DTPA t{sub 1/2} values in these three patients occurred 35-84 days before clinical symptoms and/or radiographic changes; and (f) DTPA t{sub 1/2} tended to approach baseline values with time after radiotherapy, suggesting a long-term recovery in lung injury.
- OSTI ID:
- 560592
- Journal Information:
- Journal of Nuclear Medicine, Vol. 38, Issue 6; Other Information: PBD: Jun 1997
- Country of Publication:
- United States
- Language:
- English
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