The European Association of Nuclear Medicine
Bajc M, et al. Eur J Nucl Med Mol Imaging 2009; 36: 1356-1370
Bajc M, et al. Eur J Nucl Med Mol Imaging 2009; 36: 1528-1538
The Canadian Association of Nuclear Medicine
Technegas Functional Lung Imaging
Ventilation SPECT/CT using Technegas to quantify pulmonary function
Ventilation-perfusion (V/Q) SPECT using Technegas to detect pulmonary embolism
Beyond PE clinical uses - results from clinical studies
Airflow limitation assessment in chronic airway diseases
Images were kindly provided by the Hunter New England Imaging (HNEI) at John Hunter Hospital and clinical data by the Hunter Medical Research Institute (HMRI)
Monitoring treatment response in asthmatic patients
Images and clinical data were kindly provided by the Woolcock Institute of Medical Research
Lung function evaluation before lung volume reduction surgery
Images were kindly provided by Macquarie Medical Imaging (MMI) and clinical data by Macquarie Respiratory & Sleep department at Macquarie University
Pre-existing lung disease should not be a relative contraindication to the use of V/Q SPECT-CT. This modality has a sensitivity of 100% and specificity of 94% with lower radiation doses compared to CTPA.
We recommend nuclear V/Q lung scanning instead of CTPA as a screening test to rule out the possibility of CTEPH in patients diagnosed with PH. A normal V/Q scan effectively rules out the possibility of CTEPH.
99mTc-Technegas ventilation scintigraphy is an established and well-studied tool for imaging of lung ventilation and combined SPECT/CT has been shown to improve overall diagnostic accuracy in many areas of pulmonary nuclear medicine.
Compared to the currently available scanning technologies for diagnosing suspected PE, SPECT/CT appears to confer superior economic value, primarily via improved sensitivity and specificity and low non-diagnostic rates. In turn, the improved diagnostic accuracy accords this modality the lowest ratio of expenses attributable to potentially avoidable complications, misdiagnosis and underdiagnosis.
The introduction of the tomographic technique and the implementation of Technegas as a novel ventilation agent facilitated imaging of pulmonary embolism in comparison with planar imaging and particularly in COPD patients together with the new interpretation criteria.
We recommend that SPECT/CT based quantification be used for all lung cancer patients undergoing pre-therapy evaluation of regional lung function.
Ventilation imaging is most often performed in conjunction with lung perfusion to characterize perfusion defects as a matched, mismatched or reverse mismatched.
The optimal tracer for ventilation studies is Technegas, an ultra fine dispersion of 99mTc-labeled carbon. Despite that Technegas is not approved for use in the United States, it is used in 79% of ventilation imaging studies performed in Canada and is also commonly used in Europe. Its main advantage is greater percentage deposition in the alveolar spaces and less undesirable adherence to the central airways, compared with droplet radioaerosols.
Using 99mTc-Technegas has minimized the problem of hotspots in patients with obstructive lung disease and is according to clinical experience better than the best liquid aerosols.
V/Q SPECT, using Technegas as the ventilation imaging agent, could diagnose and grade severity of COPD and also estimate preserved lung function in 94 patients. Moreover, V/Q SPECT appears to be a unique tool to reveal the heterogeneity of COPD caused by pulmonary comorbidities such as pulmonary embolism, left heart failure, lung tumor and pneumonia. The characteristics of these comorbidities suggest their significant impact in symptoms, their influence on prognosis and their response to treatment.