CT — Torace: VIDA (MCB)

Updated 05/01/24 CT Chest VIDA (Quantitative) Reviewed 05/14/25 Indications - quantitative CT (QCT) imaging in the setting of airway obstruction /COPD and should be ordered as VIDA protocol by Pulmonology. Use CT Chest without Contrast charge. GENERAL SCAN NOTES The patient's arms must be over his/her head. Remove any metal from the imaging field of view. Have the patient cough a few times to clear secretions. This reduces incidence of small lung nodules. Topogram - lung apices through diaphragm (obtained during end inspiration). Craniocaudal scan coverage - lung apices through adrenal glands (obtained during maximum end inspiration). Adjust FOV (field of view) on topogram to smallest without cropping anatomy. Technique (mAs, kV, etc) and FOV must be the same for every scan for a given patient. See end of protocol for requirements for the axial thins recons. IV Contrast: not given for this protocol. SIEMENS PARAMETERS & RECONS Scan
Care
Eff mAs Scan
Mode kV Care
Dose Pitch Acq Coll Rot kV & Lvl Time Time NA 16 0.5 0.75 12.5 Sensation 16 spiral 120 90/110/160 off 1.00 0.8 8.3 Go Up 32 spiral 110 off 1.20 32 0.75 90/110/160 off Sensation 64 spiral 64 0.6 0.5 NA 1.00 7.8 120 off 80/100/150 Definition 64 spiral 64 0.6 0.5 7.8 120 off 1.00 80/100/150 off Go Top 64 spiral 120 1.00 64 0.6 0.5 3.9 80/100/150 off off 1.00 128 0.6 0.5 3.9 100/125/180 Drive 128 spiral 120 off off 3.9 0.6 0.5 Force 192 spiral 120 off 100/125/180 1.00 128 off Use lower mAs for BMI <20, mid mAs for BMI 20-30 and higher mAs for BMI >30. Recon
Name of Series Thick Interval Kernel Window IR
Lvl Direction AX LUNG 3.0 3.0 Br57 / B70f lung none head/feet AX SOFT 3.0 3.0 Br40 / B41f mediastinum none head/feet COR SOFT 3.0 3.0 Br40 / B41f mediastinum none front/back SAG SOFT 3.0 3.0 Br40 / B41f mediastinum none left/right TLC INSP 1 0.75 0.5 mediastinum Qr36f / B35f none head/feet VIDA specific recons. TLC INSP 2 0.75 0.5 Br46f / B45f mediastinum none head/feet AX MIPS 8.0 3.0 Br40 / B41f lung none head/feet

CT Chest VIDA (Quantitative) GE PARAMETERS & RECONS Scan
Slice
Beam
Dose
Scan
Manual
ASIR Type SFOV kV Smart
mA Thick Pitch Speed Rot
Coll Time Red Time mA LS 16 helical large 120 NA 20 0.625 1.375 27.50 off 0.5 NA 5.5 145/180/270 Opt 540 helical large 120 20 0.625 1.375 off 27.50 0.5 NA NA 5.5 145/180/270 LS VCT 64 helical large body 120 off off 40 0.625 0.984 39.37 0.5 none 3.8 145/180/270 Disc VCT 64 helical large body 120 40 0.625 off 0.984 39.37 0.5 NA NA 3.8 145/180/270 Use lower mAs for BMI <20, mid mAs for BMI 20-30 and higher mAs for BMI >30. Window
Recon
Name of Series Thickness Interval Recon
Algorithm Width/Level Direction TLC INSP 0.625 0.5 std full 400/40 head/feet This must be the first recon. AX LUNG 2.5 2.5 lung 1600/-600 head/feet VIDA specific recon. AX SOFT 2.5 2.5 std full 400/40 head/feet COR SOFT 2.5 2.5 std full 400/40 front/back SAG SOFT 2.5 2.5 std full 400/40 left/right AX MIPS 8.0 3.0 std full 1600/-600 head/feet PHILIPS PARAMETERS & RECONS Scan
3D
Rot Scan
mA Mode kV Dose Pitch Detect Colli Time Time Incisive 128 helical 120 off 0.923 64 0.625 0.5 4.1 105/130/190 Use lower mAs for BMI <20, mid mAs for BMI 20-30 and higher mAs for BMI >30. Recon
Name of Series Thick Interval Filter Window iDose Direction AX LUNG 3.0 3.0 YA lung none head/feet AX SOFT 3.0 3.0 B mediastinum none head/feet COR SOFT 3.0 3.0 B mediastinum none front/back SAG SOFT 3.0 3.0 B mediastinum none left/right TLC INSP B mediastinum none 0.75 0.5 head/feet VIDA specific recon. AX MIPS 8.0 2.0 B lung none head/feet

CT Chest VIDA (Quantitative) For the Axial TLC Thins recons: The cranial/top image should begin 1-2 slices above the top of both lungs. The caudal/bottom image should stop 1-2 slices below the bottom of both lungs. The FOV of the transverse/axial plane should tightly fit the lungs (outer rib to outer rib at widest part of the chest).

CT TECHNOLOGIST INSTRUCTION FORM

CT-90053: Siemens Somatom Drive

Issued by: Quality Assurance

Eff. Date: 05/22/19 Rev A.1
Pg. 1 of 3

It is important that the subject fully understands the breath hold and scanning procedure and that all concerns are addressed prior to performing the CT scan. If this is a subsequent visit to the baseline visit, participants must be scanned with the same CT acquisition and reconstruction parameters used during the baseline CT visit.

Subject Positioning • Place subject in a supine position, arms positioned comfortably above the head in a head-arm rest, lower legs supported. • Using the laser positioning lights, line up the subject so the chest is iso-center (in the middle: left-right; up- down) of the CT gantry. Correcting an off-center subject during image reconstruction is not acceptable. Proper positioning must be ensured prior to scanning. • Move the table so the subject is in the correct position for a chest CT scan. • Once the subject is comfortably and properly positioned, remain in the scanner room and work with the subject to rehearse the breathing instructions used during CT acquisition several times. It is important that the subject fully understands the breath hold and scanning procedure and that all concerns are addressed prior to performing the CT scan.

Scan Coverage CT scan must include the entire lungs, but ONLY the lungs. Start the scan precisely at the apex of the lungs and stop it once the scan is through the base of the lungs as shown in Figure 1.
• The DFOV should tightly fit the TLC lung for the QCT reconstruction as shown in Figure 2. • The same DFOV should be used for all time points of a given subject.

Figure 1 Figure 2

Approved by/date: J Sieren 5/22/19 This document is the property of VIDA Diagnostics, Inc.
Unauthorized use of this document is prohibited. Note: Always check Document Control Master List for current revision prior to using.

CT TECHNOLOGIST INSTRUCTION FORM

CT-90053: Siemens Somatom Drive

Issued by: Quality Assurance

Eff. Date: 05/22/19 Rev A.1
Pg. 2 of 3

CT Parameters • The following parameters must be implemented for these CT scans.
• Scout scan uses default parameters (Site discretions on type and number of scouts, however must maintain ALARA principle).

Table 1: CT Protocol Siemens Somatom Drive

INSPIRATION Effective mAs Selection (TLC)

Siemens Somatom Scanner Drive Scan Type Spiral Rotation Time (s) 0.5 Det. Configuration 128 x 0.6mm kV 120 Pitch 1.0 Small, medium or large effective mAs settings for these scans are based upon the Body Mass Index (BMI). The BMI must be provided to the technologist to set the effective mAs.

All subject scanning visits post-screening will be assigned to a different dose category only if the BMI changes between clinical visits by more than 3 AND crosses the 20 or 30 BMI thresholds.

Please use the table below to select the correct effective mAs setting based on the subject’s BMI.

Dose Modulation Off Inspiration (TLC) Recon Algorithm 1
Effective mAs as a function of BMI: TLC Scan (For QCT analysis) B35 BMI Range Size Eff. mAs Recon Algorithm 2
setting to be (For Visual analysis) B45 used < 20 Small (S) 100 Iterative Recon Do not use IRIS or 20-30 Medium (M) 125 (noise reduction) SAPHIRE > 30 Large (L) 180

Thickness (mm) 0.75 Interval (mm) 0.5 Est. Scan Time (Sec)

30cm length <10

Approved by/date: J Sieren 5/22/19 This document is the property of VIDA Diagnostics, Inc.
Unauthorized use of this document is prohibited. Note: Always check Document Control Master List for current revision prior to using.

CT TECHNOLOGIST INSTRUCTION FORM

CT-90053: Siemens Somatom Drive

Issued by: Quality Assurance

Eff. Date: 05/22/19 Rev A.1
Pg. 3 of 3

The following breathing instructions must be given to the subject: * Bold instructions are what must be said to the subject during CT. ** (Italic) information represents reminders directed towards the CT technologist.

SCANNING: Use the breathing instructions to perform: • A practice breathing session • Scouts - as needed - to position the FOV to cover the entire lung and as little soft tissue as possible • The Inspiration CT scan (TLC)

Inspiratory CT (TLC)

BREATHING INSTRUCTIONS: For this scan, I am going to ask you to take a couple of deep breaths in and out before we have you breathe all the way in and hold your breath.

Ok, let’s get started, Take a deep breath in (watch chest to ensure a deep breath in) Let it out (watch chest to ensure air is out) Take a deep breath in (watch chest to ensure a deep breath in) Let it out (watch chest to ensure air is out) Now breathe all the way IN...IN...IN (watch chest to ensure a deep breath in as far as possible) Keep holding your breath – DO NOT BREATHE! At end of scan or practice: - Breathe and relax

Approved by/date: J Sieren 5/22/19 This document is the property of VIDA Diagnostics, Inc.
Unauthorized use of this document is prohibited. Note: Always check Document Control Master List for current revision prior to using.

CT TECHNOLOGIST INSTRUCTION FORM

CT-90059: Siemens Somatom Go. Up 32

Issued by: Imaging Services

Eff. Date: 6/23/2020

Rev A
Pg. 1 of 3

It is important that the subject fully understands the breath hold and scanning procedure and that all concerns are addressed prior to performing the CT scan. If this is a subsequent visit to the baseline visit, participants must be scanned with the same CT acquisition and reconstruction parameters used during the baseline CT visit.

Subject Positioning • Place subject in a supine position, arms positioned comfortably above the head in a head-arm rest, lower legs supported. • Using the laser positioning lights, line up the subject so the chest is iso-center (in the middle: left-right; up-down) of the CT gantry. Correcting an off-center subject during image reconstruction is not acceptable. Proper positioning must be ensured prior to scanning. • Move the table so the subject is in the correct position for a chest CT scan. • Once the subject is comfortably and properly positioned, remain in the scanner room and work with the subject to rehearse the breathing instructions used during CT acquisition several times. It is important that the subject fully understands the breath hold and scanning procedure and that all concerns are addressed prior to performing the CT scan.

Scan Coverage CT scan must include the entire lungs, but ONLY the lungs. Start the scan precisely at the apex of the lungs and stop it once the scan is through the base of the lungs as shown in Figure 1.
• The DFOV should tightly fit the TLC lung for the QCT reconstruction as shown in Figure 2. • The same DFOV should be used for the TLC and RV scans. • The same DFOV should be used for all time points of a given subject.

Figure 1 Figure 2

Approved by/date: J Schirm 6/23/2020 This document is the property of VIDA Diagnostics, Inc.
Unauthorized use of this document is prohibited. Note: Always check Document Control Master List for current revision prior to using.

CT TECHNOLOGIST INSTRUCTION FORM

CT-90059: Siemens Somatom Go. Up 32

Issued by: Imaging Services

Eff. Date: 6/23/2020

Rev A
Pg. 2 of 3

The following breathing instructions must be given to the subject: * Bold instructions are what must be said to the subject during CT. ** (Italic) information represents reminders directed towards the CT technologist.

SCANNING: Use the breathing instructions to perform: • A practice breathing session • Scouts - as needed - to position the FOV to cover the entire lung and as little soft tissue as possible • The Inspiration CT scan (TLC)

Inspiratory CT (TLC)

BREATHING INSTRUCTIONS: For this scan, I am going to ask you to take a couple of deep breaths in and out before we have you breathe all the way in and hold your breath.

Ok, let’s get started, Take a deep breath in (watch chest to ensure a deep breath in) Let it out (watch chest to ensure air is out) Take a deep breath in (watch chest to ensure a deep breath in) Let it out (watch chest to ensure air is out) Now breathe all the way IN...IN...IN (watch chest to ensure a deep breath in as far as possible) Keep holding your breath – DO NOT BREATHE! At end of scan or practice: - Breathe and relax

Approved by/date: J Schirm 6/23/2020 This document is the property of VIDA Diagnostics, Inc.
Unauthorized use of this document is prohibited. Note: Always check Document Control Master List for current revision prior to using.

CT TECHNOLOGIST INSTRUCTION FORM

CT-90059: Siemens Somatom Go. Up 32

Issued by: Imaging Services

Eff. Date: 6/23/2020

Rev A
Pg. 3 of 3

CT Parameters • The following parameters must be implemented for these CT scans.
• Scout scan uses default parameters (Site discretions on type and number of scouts, however must maintain ALARA principle).
Table 1: CT Protocol Siemens Somatom Go.Up 32

INSPIRATION Effective mAs Selection (TLC)

Scanner Somatom Go.Up
Scan Type Spiral (single source) Rotation Time (s) 0.8 Det. Configuration 32 x 0.7mm kV 110 Pitch 1.2 Dose Modulation Off Recon Algorithm 1
Small, medium or large Effective mAs settings for these scans are based upon the Body Mass Index (BMI). The BMI must be provided to the technologist to set the Effective mAs.

All subject scanning visits post-screening will be assigned to a different dose category only if the BMI changes between clinical visits by more than 3 AND crosses the 20 or 30 BMI thresholds.

Please use the table below to select the correct Effective mAs setting based on the subject’s BMI.

(For QCT analysis) B35 Inspiration (TLC) Recon Algorithm 2 Effective mAs as a function of BMI: TLC Scan BMI Range Size Eff. mAs (For Visual setting to be analysis) B45 used Iterative Recon < 20 Small (S) 90 (noise reduction) Do not use IRIS or SAPHIRE 20-30 Medium (M) 110 > 30 Large (L) 160 Thickness (mm) 0.75

Interval (mm) 0.5 Est. Scan Time

(Sec) <20 30cm length

Approved by/date: J Schirm 6/23/2020 This document is the property of VIDA Diagnostics, Inc.
Unauthorized use of this document is prohibited. Note: Always check Document Control Master List for current revision prior to using.

CT TECHNOLOGIST INSTRUCTION FORM

CT-90043: SIEMENS SENSATION 64

Issued by: Quality Assurance

Eff. Date: 6/9/2014
Rev D
Pg. 1 of 3

It is important that the subject fully understands the breath hold and scanning procedure and that all concerns are addressed prior to performing the CT scan. If this is a subsequent visit to the baseline visit, participants must be scanned with the same CT acquisition and reconstruction parameters used during the baseline CT visit.

Subject Positioning  Place subject in a supine position, arms positioned comfortably above the head in a head-arm rest, lower legs supported.  Using the laser positioning lights, line up the subject so the chest is iso-center (in the middle: left-right; up- down) of the CT gantry. Correcting an off-center subject during image reconstruction is not acceptable. Proper positioning must be ensured prior to scanning.  Move the table so the subject is in the correct position for a chest CT scan.  Once the subject is comfortably and properly positioned, remain in the scanner room and work with the subject to rehearse the breathing instructions used during CT acquisition several times. It is important that the subject fully understands the breath hold and scanning procedure and that all concerns are addressed prior to performing the CT scan.

Scan Coverage CT scan must include the lungs, but ONLY the lungs. Start the scan precisely at the apex of the lungs and stop it once the scan is through the base of the lungs as shown in figure 1.
 The DFOV should tightly fit the TLC lung for the QCT reconstruction as shown in figure 2.  The same DFOV should be used for the TLC and RV scans.  The same DFOV should be used for all time points of a given subject.

Figure 1 Figure 2

Approved by/date: Susan Wood, 6/9/2014 This document is the property of VIDA Diagnostics, Inc.
Unauthorized use of this document is prohibited. Note: Always check Document Control Master List for current revision prior to using.

CT TECHNOLOGIST INSTRUCTION FORM

CT-90043: SIEMENS SENSATION 64

Issued by: Quality Assurance

Eff. Date: 6/9/2014
Rev D
Pg. 2 of 3

CT Parameters  The following parameters must be implemented for these CT scans.
 Scout scan uses default parameters (Site discretions on type and number of scouts, however must maintain ALARA principle).

Table 1: CT Protocol Siemens Sensation 64

Effective mAs Selection

Scanner Sensation 64 Scan Type Spiral Rotation Time (s) 0.5 Det. Configuration 64 x 0.6mm kV 120 Pitch 1.0 Dose Modulation Off Small, medium or large effective mAs settings for these scans are based upon the Body Mass Index (BMI). The BMI must be provided to the technologist to set the effective mAs.

All subject scanning visits post-screening will be assigned to a different dose category only if the BMI changes between clinical visits by more than 3 AND crosses the 20 or 30 BMI thresholds.

Please use the table below to select the correct effective mAs setting based on the subject’s BMI.

Recon Algorithm 1
Effective mAs as a function of BMI: TLC Scan (For QCT analysis) B35 BMI Range Size Eff. mAs Recon Algorithm 2
setting to be (For Visual analysis) B45 used Iterative Recon Do not use IRIS or < 20 Small (S) 80 (noise reduction) SAPHIRE 20-30 Medium (M) 100 > 30 Large (L) 150 Thickness (mm) 0.75

Interval (mm) 0.5 Est. Scan Time (Sec)

30cm length <10

Approved by/date: Susan Wood, 6/9/2014 This document is the property of VIDA Diagnostics, Inc.
Unauthorized use of this document is prohibited. Note: Always check Document Control Master List for current revision prior to using.

CT TECHNOLOGIST INSTRUCTION FORM

CT-90043: SIEMENS SENSATION 64

Issued by: Quality Assurance

Eff. Date: 6/9/2014
Rev D
Pg. 3 of 3

The following breathing instructions must be given to the subject: * Bold instructions are what must be said to the subject during CT. ** (Italic) information represents reminders directed towards the CT technologist.

SCANNING: Use the breathing instructions to perform:  A practice breathing session  Scouts - as needed - to position the FOV to cover the entire lung and as little soft tissue as possible  The Inspiration CT scan (TLC)

Inspiratory CT (TLC)

BREATHING INSTRUCTIONS: For this scan, I am going to ask you to take a couple of deep breaths in and out before we have you breathe all the way in and hold your breath.

Ok, let’s get started, Take a deep breath in (watch chest to ensure a deep breath in) Let it out (watch chest to ensure air is out) Take a deep breath in (watch chest to ensure a deep breath in) Let it out (watch chest to ensure air is out) Now breathe all the way IN...IN...IN (watch chest to ensure a deep breath in as far as possible) Keep holding your breath – DO NOT BREATHE! At end of scan or practice: - Breathe and relax

Approved by/date: Susan Wood, 6/9/2014 This document is the property of VIDA Diagnostics, Inc.
Unauthorized use of this document is prohibited. Note: Always check Document Control Master List for current revision prior to using.

PULMONARY PERSPECTIVE Table 2. Scanner-Specific Protocol Settings Scanner Make Siemens Siemens Siemens GE GE Philips Scanner model Definition (AS Plus) 128 slice Definition (DS) 64 slice Sensation 64 slice VCT 64 slice/ Discovery STE Discovery CT 750HD 64 slice Brilliance 64 slice Scan type Spiral Spiral single source Spiral Helical Helical - standard Spiral helix Scan FOV No selection No selection No selection Large Large No selection Rotation time, s 0.5 0.5 0.5 0.5 0.5 0.5 Detector configuration 128 3 0.6 64 3 0.6 64 3 0.6 64 3 0.625 64 3 0.625 64 3 0.625 Pitch 1.0 1.0 1.0 0.984 0.984 0.923 kVp 120 120 120 120 120 120 Inspiration (TLC) Effective mAs Effective mAs Effective mAs mA mA mAs Small 90 85 80 145 145 105 Medium 110 105 100 180 180 130 Large 165 150 145 270 270 190 Expiration (RV) Effective mAs Effective mAs Effective mAs mA mA mAs Extra small 60 Small 55 50 100 100 70 Medium/large 90 85 80 145 145 105 Dose modulation Care dose off Care dose off Care dose off Auto mA off Auto mA off Dose right (ACS) off Standard algorithm B35 B35 B35 Standard Standard B Lung algorithm B30 B31 None Detail Detail YB Additional image filters No selection No selection No selection No selection IQ enhance off Adaptive filtering off Thickness, mm 0.75 0.75 0.75 0.625 0.625 0.67 Interval, mm 0.5 0.5 0.5 0.5 0.5 0.5 Iterative reconstruction (noise reduction algorithm) Do not use IRIS Do not use IRIS No selection Do not use ASIR Do not use ASIR Do not use iDOSE Scan time, 30-cm length, s ,10 ,10 ,10 ,10 ,10 ,10 Reconstruction mode N/A N/A N/A Plus Plus N/A Smart mA N/A N/A N/A Off Off N/A Definition of abbreviations: ACS = automatic current selection; ASIR = adaptive statistical iterative reconstruction; CT = computed tomography; FOV = field of view; IQ = intelligent quantitation; IRIS = iterative reconstruction in image space; kVp = peak kilovoltage; mAs = milliamperage seconds; N/A = not applicable; RV = residual volume; TLC = total lung capacity. Standardizing on volumetric computed tomography dose index, protocols were developed for each scanner type within SPIROMICS (Subpopulations and Intermediate Outcome Measures in COPD Study) so as to maximize the similarity of image data across sites. At each of the two lung volumes, the CT protocol specifies the scanner model, scan mode, scan FOV, rotation time, detector configuration, pitch, kVp, mAs, dose modulation setting, reconstruction kernels, post-processing filter settings, slice thickness, slice interval, iterative reconstruction algorithm setting, scan time for 30-cm length, reconstruction mode, smart mA setting, and IQ enhance setting. Effective mAs represents the tube current–time product. At the time of training, it is emphasized that positioning of the patient in the isocenter of the CT scanner aperture is critical, as discussed in the report from the American College of Radiology (ACR) CT accreditation program (24). Isocenter positioning serves to reduce cone-beam and scatter artifacts. Step 2: CT scanner calibration status. SPIROMICS requires that each scanner pass an initial calibration check. Scanners must have 64 detector rows or higher to provide imaging speeds adequate for a breath-hold. Precertified scanner information must also be preloaded into the QCT-LAS before onset of subject imaging. Each CT manufacturer has their own scanner-specific test object (“phantom”) that assesses the calibration of several general scanner parameters, such as the value of water that should be 0 HU. The SPIROMICS CT protocol includes a specialized CT test object (referred to as the “COPDGene 1” test object) developed in the COPDGene study (25). Assurance of measurement stability of a given CT scanner is critical to any quantitative CT effort. If test object Hounsfield unit values shift by more than 3 HU in any material, the site is alerted and action is taken. Guidelines have been developed for the automated assessment of the appropriate positioning of the test object within the scanner to assure that object misalignment is not contributing to measured deviations (26). Step 3: Scan acquisition and data entry. SPIROMICS developed Procedural Verification Software (PVS) to provide scanner information and track scan data in real time (Figure E2A). PVS provides an automated web portal system requiring a local computer and Internet connection. The main function of PVS is to provide a mechanism for subject registration before scanning and to provide the study coordinator with subject- and scanner- specific scan parameters from the QCT-LAS database using the subject’s BMI. In a longitudinal study, such as SPIROMICS, PVS assures that follow-up scans match the baseline scan in terms of scan protocol, including scanning on the same scanner. Details are provided in the online supplement. Written directions for the technologist (Appendix 1A and 1B) accompany the patient and include instructions to: (1) position the subject at the center of the CT scanner aperture by use of laser beams for left-to-right and ventral-to-dorsal centering, (2) scan only the z-axis length needed to include the apical to basal extent of the lungs, (3) select the display field of view (DFOV) limited to the most lateral extents of the lungs (providing maximal spatial resolution) at TLC and to keep the DFOV the same for TLC (inspiratory volume) and RV (expiratory volume). A consistent DFOV across lung volumes and longitudinally is important for comparison of airway and density metrics. Breathing/breath-hold instructions (Appendix 2) are supplied within the CT technologist form, and technologists are instructed to coach the subject, as in a pulmonary function testing laboratory, to achieve both TLC and RV with a series of proceeding deep inspirations. Recorded instructions should not be used, as this takes the technologist’s attention off of the subject. Pulmonary Perspective 797

PULMONARY PERSPECTIVE Appendix 1 (A and B) Computed tomography (CT) technologist instruction forms. These forms provide information to ensure the technologists have all the proper information to complete the examinations within the guidelines of the study. The forms are made available through the Procedural Verification Software web system and may be downloaded and printed to take to the scanner room or used for study reference. ALARA = as low as reasonably achievable; DFOV = display field of view; mAs = milliamperage seconds; RV = residual volume; TLC = total lung capacity. 804 American Journal of Respiratory and Critical Care Medicine Volume 194 Number 7 | October 1 2016

PULMONARY PERSPECTIVE Pulmonary Perspective 805

PULMONARY PERSPECTIVE Appendix 2 Each computed tomography (CT) technologist form contains proper breathing instructions for a given site’s scanner at the time of scanning the subjects. The form is made available through the Procedural Verification Software web system and may be downloaded and printed to take to the scanner room or used for study reference. FOV = field of view; RV = residual volume; TLC = total lung capacity. 806 American Journal of Respiratory and Critical Care Medicine Volume 194 Number 7 | October 1 2016