Vol 6, No 1 (2003)
Published online: 2003-01-03
Simultaneous 13C/14C dual isotope breath test measurement of gastric emptying of solid and liquid in normal subjects and patients: comparison with scintigraphy
Nucl. Med. Rev 2003;6(1):29-33.
Abstract
BACKGROUND: To develop a simple method for simultaneous solid and liquid gastric emptying assessment using a dual isotope labelled breath test.
MATERIAL AND METHODS: 13 patients were given 100 g ground beef labelled with 25 MBq 99mTc sulphur colloid and 74 KBq 14C octanoic acid, and 150 ml 10% glucose drink labelled with 8 MBq 67Ga citrate and 150 mg 13C acetate. 10 normal volunteers were given the same test meals but labelled with 14C and 13C only. Breath was collected at baseline and regularly for 4 hours. The 14CO2 and 13CO2 activity was measured with liquid scintillation counting and mass spectroscopy. The times to maximum 14CO2 and 13CO2, were determined. Comparison was made between times to maximum 14CO2 with scintigraphic retention of 99mTc at 100 minutes and times to maximum 13CO2 with the scintigraphic half-clearance time of 67Ga.
RESULTS: For the solid meal, the times to maximum 14CO2 were: 60–120 minutes in the 8 patients with normal gastric emptying of 99mTc; 75–145 minutes for the 10 healthy volunteers; 75–180 minutes for the remaining 5 patients with abnormal gastric emptying of 99mTc. There was a weak but significant correlation (r = 0.56, p < 0.025) between the time to maximum 14CO2 and gastric retention of 99mTc at 100 minutes. For the liquid meal, times to maximum 13CO2 were: 20–35 minutes for the 4 with normal gastric emptying of 67Ga; 15–40 minutes for the 10 healthy volunteers; 20–75 minutes for the remaining 9 patients with abnormal gastric emptying of 67Ga. There was a strong and significant correlation (r = 0.88, p < 0.005) between times to maximum 13CO2 and gastric half-clearance time of 67Ga.
CONCLUSIONS: Breath tests utilising test meals labelled with *C isotopes are valid alternatives to scintigraphic studies using 99mTc and 67Ga for the simultaneous assessment of gastric emptying of solids and liquids.
MATERIAL AND METHODS: 13 patients were given 100 g ground beef labelled with 25 MBq 99mTc sulphur colloid and 74 KBq 14C octanoic acid, and 150 ml 10% glucose drink labelled with 8 MBq 67Ga citrate and 150 mg 13C acetate. 10 normal volunteers were given the same test meals but labelled with 14C and 13C only. Breath was collected at baseline and regularly for 4 hours. The 14CO2 and 13CO2 activity was measured with liquid scintillation counting and mass spectroscopy. The times to maximum 14CO2 and 13CO2, were determined. Comparison was made between times to maximum 14CO2 with scintigraphic retention of 99mTc at 100 minutes and times to maximum 13CO2 with the scintigraphic half-clearance time of 67Ga.
RESULTS: For the solid meal, the times to maximum 14CO2 were: 60–120 minutes in the 8 patients with normal gastric emptying of 99mTc; 75–145 minutes for the 10 healthy volunteers; 75–180 minutes for the remaining 5 patients with abnormal gastric emptying of 99mTc. There was a weak but significant correlation (r = 0.56, p < 0.025) between the time to maximum 14CO2 and gastric retention of 99mTc at 100 minutes. For the liquid meal, times to maximum 13CO2 were: 20–35 minutes for the 4 with normal gastric emptying of 67Ga; 15–40 minutes for the 10 healthy volunteers; 20–75 minutes for the remaining 9 patients with abnormal gastric emptying of 67Ga. There was a strong and significant correlation (r = 0.88, p < 0.005) between times to maximum 13CO2 and gastric half-clearance time of 67Ga.
CONCLUSIONS: Breath tests utilising test meals labelled with *C isotopes are valid alternatives to scintigraphic studies using 99mTc and 67Ga for the simultaneous assessment of gastric emptying of solids and liquids.
Keywords: 14C octanoic acid13C acetatebreath testgastric emptying
