Table 3.
NCCT chest protocols according to indications
| Routine NCCT/standard dose CT | Low-dose CT | Ultra Low-Dose CT | |
|---|---|---|---|
| Indications | Suspected pulmonary metastases ILD Bronchiectasis Deranged renal parameters Febrile neutropenia |
ILD evaluation* Lung cancer screening Follow-up imaging for nodules/pulmonary infections, bronchiectasis, ABPA, CF |
Lung cancer screening/nodule detection Screening lung as a part of coronary CTs. |
| Acquisition protocol | |||
| kVp | 100 (<~80kg) 120 (~80-113kg) 140 (>113kg) |
80-120 | 120-140 |
| mA with AEC | 35 | 22 | Without AEC |
| Tube current (mAs) | 130-200 | 20-40 | Employs a fixed mAs value- 10 |
| Collimation | Lowest possible on the scanner (e.g. 0.6) | Lowest possible on the scanner | Lowest possible on the scanner |
| Pitch | 1.2 | Highest pitch | NS |
| Rotation time | 0.5 | 0.5 | NS |
| Slice thickness | 1.2-1.5mm | 1.2-1.5mm | NS |
| Matrix | 512×512 | 512×512 | 512 × 512 |
| Expected Radiation Dose | 3-8 mSv# | 1-3 mSv | 0.182±0.028mSv i.e. <1 mSv |
*Use of LDCT in ILD is recent concept, explained in text.; ABPA- Allergic bronchopulmonary aspergillosis; CF- Cystic fibrosis; ILD - interstitial lung diseases; NS- Non specified. #With modern scanners and availability of iterative reconstructions, a radiation dose of 2-3mSv is possible