Technegas is an ultra-fine dispersion of Technetium-labelled carbon, produced by heating Technetium-99m in a carbon crucible for a few seconds at 2,750 degrees Celsius1. The resultant gas-like Technegas, thus produced in a Technegas generator, is a cluster of nanosized (average size 30-60nm) pure carbon platelets of hexagonal shape fully encapsulating Technetium metal crystals2. The small size and hydrophobic properties together confirm ideal characteristics for gas-like behaviour and alveoli deposition into the lungs2-3.
Once inhaled by the patient suspected of having a pulmonary embolism, the patient is then imaged under a gamma camera in the ventilation part of a ventilation/perfusion single-photon emission computed tomography (V/Q SPECT) scan3. Technegas penetrates to the sub-segmental areas of the lung and is trapped by surfactant in the alveolar walls4.
Generated into a mobile generator, Technegas, used in the ventilation part of the V/Q scan, is cost-effective, simple to perform and accurate5. With the uptake in SPECT imaging, V/Q SPECT results with Technegas can be argued to be superior to planar imaging and computed tomography (CT) when comparing sensitivity, accuracy and negative predictive value6.
Diagnostic ability of CT, V/Q SPECT and Planar V/Q Scintigraphy to detect pulmonary embolism6:
|Negative predictive value||
Table adapted from Reinartz P et al, J Nucl Med 2004; 45: 1501-1508
Of significant interest, when compared to CT, is the low radiation dose imparted by V/Q SPECT imaging7. This is important in all patients but particularly in young women with proliferating breast tissue8.
“Lung Scintigraphy has a superior sensitivity combined with adequate specificity and low rate of non-diagnostic tests. The low radiation dose, the possibility to quantify the degree of embolism and to use the test for follow-up of treatment of embolism and its feasibility in very sick patients, contribute to the priority of lung scintigraphy over Computed Tomographic Pulmonary Angiography”9.
|Add up the benefits using Technegas|
Proven diagnostic accuracy: Sensitivity, specificity and accuracy at least equivalent of CTPA5giving the clinician interpretative confidence first time every time.
Non-invasive10: Aids patients comfort and compliance.
Detects PE: Even at subsegmental levels6,11.
Low radiation burden to the patient: V/Q SPECT with Technegas has 27 to 36 times less radiation dose to the patient breast as compared with CTPA7.
Minimal exclusion criteria: Technegas may be administered to almost all patients including:
Why Technegas for ventilation imaging
|For the Clinician||For the Technologist|
Quick reliable administration of Technegas
||Quick and simple automated
|Gas like behaviour of Technegas coupled with the ideal energy of Tc-99m3,15
||Rapid and easy administration (2-3 breaths suffice for most patients)15
|Images may be acquired in multiple projections14
||Reduced radiation exposure to operator and to patient7
|Long residence time16 and absence of redistribution enables acquisition of high quality SPECT images14
||Minimal camera time required8,19
|V/Q SPECT using Technegas yields a 96% sensitivity and a 97% specificity18
||Flexible solution to your needs
|Provides a simple answer to a single question.
||Exceptional image quality14
|Minimal radiation burden for the patient7
- Fawdry RM, et al. Initial experience with Technegas – a new ventilation agent. Australas Radiol 1988; 32(2): 232-238
- Senden TJ, et al. The physical and chemical nature of Technegas. J Nucl Med 1997; 38: 1327-1333
- Roach PJ, Schembri GP and Bailey DL. V/Q scanning using SPECT and SPECT/CT. J Nucl Med 2013; 54: 1588-1596
- Mortensen J and Gutte H. SPECT/CT and pulmonary embolism. Eur J Nucl Med Mol Imaging 2014; 41(Suppl1): 81-90
- Roach PJ, Bailey DL, Harris BE. Enhancing lung scintigraphy with single-photon emission computed tomography. Semin Nucl Med 2008; 38: 441–449
- Reinartz P, et al. Tomographic imaging in the diagnosis of pulmonary embolism: A comparison between V/Q lung scintigraphy in SPECT technique and multislice spiral CT. J Nucl Med 2004; 45: 1501-1508
- Isidoro J, et al. Radiation dose comparison between V/P-SPECT and CT-angiography in the diagnosis of pulmonary embolism. Phys Med 2017; 41: 93-96
- Bajc et al. V/P SPECT as a diagnostic tool for pregnant women with suspected pulmonary embolism. Eur J Nucl Mol Imaging 2015; 42: 1325-1330
- Bajc et al. Comparison of ventilation/perfusion scintigraphy and helical CT for diagnosis of pulmonary embolism; strategy using clinical data and ancillary findings. Clin Physiol Funct Imaging 2002; 22(6): 392-397
- Sánchez-Crespo A, et al. A technique for lung ventilation-perfusion SPECT in neonates and infants. Nucl Med Commun 2008; 29(2): 173-177
- Grüning T, et al. Three-year experience with VQ SPECT for diagnosing pulmonary embolism: diagnostic performance. Clin Imaging 2014; 38(6): 831-835
- Miles S, et al. A comparison of single-photon emission CT lung scintigraphy and CT pulmonary angiography for the diagnosis of pulmonary embolism. Chest 2009; 136: 1546-1553
- Nasr A, Lindqvist A and Bajc M. Ventilation defect typical for COPD is frequent among patients suspected for pulmonary embolism but does not prevent the diagnosis of PE by V/P SPECT. EC Pulmonology and Respiratory Medicine 2017; 4(3): 85-91
- Hess S and Madsen PH. Radionuclide diagnosis of pulmonary embolism. Adv Exp Med Biol 2017; 906: 49-65
- Bajc M and Jonson B. Ventilation/perfusion SPECT for diagnosis of pulmonary embolism and other diseases. Int J Mol Imaging 2011; 682949
- Bajc M, et al. EANM guidelines for ventilation/perfusion scintigraphy. Part 1. Pulmonary imaging with ventilation/perfusion single photon emission computed tomography. Eur J Nucl Med Mol Imaging 2009; 36: 1356-1370
- Le Roux P, Robin P, Salaun P. New developments and future challenges of nuclear medicine and molecular imaging for pulmonary embolism. Thromb Res: [Epub ahead of print]
- Lemb M and Pohlabeln H. Pulmonary thromboembolism: a retrospective study on the examination of 991 patients by ventilation/perfusion SPECT using Technegas. Nuklearmedizin 2001; 40(6): 179-186
- Freeman LM, Glaser J and Haramati LB. Planar ventilation-perfusion imaging for pulmonary embolism: the case for outcomes medicine. Semin Nucl Med 2012; 42: 3-10
Pending market authorisation – not yet available for use
Ultralute is a revolutionary innovation that allows Nuclear Medicine departments to increase the productivity of their Tc-99m generator. It does this by allowing you to elute any amount of activity in approximately 1.5ml. By increasing the concentration of Tc-99m from an elution, the decay profile and the growth of Tc-99m from a Mo-99m/Tc 99m generator can be better utilised.