Clinical Trial Details
— Status: Completed
Administrative data
NCT number |
NCT05459311 |
Other study ID # |
STU-062016-073 |
Secondary ID |
|
Status |
Completed |
Phase |
|
First received |
|
Last updated |
|
Start date |
October 3, 2017 |
Est. completion date |
September 25, 2023 |
Study information
Verified date |
December 2023 |
Source |
University of Texas Southwestern Medical Center |
Contact |
n/a |
Is FDA regulated |
No |
Health authority |
|
Study type |
Observational
|
Clinical Trial Summary
We will conduct a prospective clinical study involving up to 40 non-Small Cell Lung Cancer
(nSCLC) patients to determine dose thresholds for central and peripheral BSS elements. All
imaging will be performed under motion control (e.g., with or without abdominal compression)
defined as breathing with a resultant motion ≤5mm by fluoroscopy.
In this study, a high-resolution breath-hold CT scan (BHCT) will be acquired from each
patient immediately before or after the 4DCT scan.
A follow-up high resolution BHCT (also under motion control) will be acquired from each
patient 8-12 months post-SabR, and BSS elements will be segmented in LungPointRT. A radiation
oncologist will compare the pre- and post-SabR contours to determine segmental collapse.
Description:
We will conduct a prospective clinical study involving up to 40 non-Small Cell Lung Cancer
(nSCLC) patients to determine dose thresholds for central and peripheral BSS elements. The
workflow is illustrated in Fig. 4. all imaging will be performed under motion control (e.g.,
with or without abdominal compression) defined as breathing with a resultant motion
[LessThanorequalTo]5mm by fluoroscopy. Before 4DCT simulation, fluoroscopy using a
stand-alone system is used to assess motion under free-breathing conditions. For those with
inherent motion [LessThanorequalTo]5mm, no motion manipulation is required (ie, motion is
controlled). For those with [Greater Than]5mm motion, it is customary to use progressively
tighter abdominal compression applied via commercially available device or a pneumatic belt,
until respiration-induced tumor motion, as seen under fluoroscopy, is [LessThanorequalTo]
5mm. Subsequently, a 4DCT scan is acquired with motion control.
in this study, a high-resolution breath-hold CT scan (BHCT) will be acquired from each
patient immediately before or after the 4DCT scan. using LungPoint, a virtual bronchoscopy
software, individual BSS will be auto-segmented from the BHCT, labeled based on a
nomenclature described by netter and exported as Digital imaging and Communications in
Medicine radiation Therapy (DiCoMRT) objects to the planning system. The BHCT will be
deformably registered to each phase of the 4DCT to create ten high-resolution CT volumes
corresponding to ten respiratory phases. acquiring both, the BHCT and the 4DCT, under motion
control will ensure that the anatomy is consistently deformed so as to minimize image
registration errors. The automatically deformed contours, especially for smaller BSS
elements, will be manually verified by a radiation oncologist, and corrected if necessary. a
high-resolution maximum intensity projection (MiP) image will be created from the deformed
BHCT volumes so as to encompass the extent of respiration-induced motion for each structure
in the lung. The high spatial resolution of the MiP will ensure that respiratory motion of
smaller, more peripheral BSS segments is captured accurately. The dose to BSS elements from
the clinical SabR plan (created without considering BSS) will be computed from the hi-res MiP
using the acuros dose calculation algorithm. This algorithm accurately accounts for dose to
small structures and tissue inhomogeneities, and has been extensively validated for lung
radiotherapy.
a follow-up high resolution BHCT (also under motion control) will be acquired from each
patient 8-12 months post-SabR, and BSS elements will be segmented in LungPointRT. a radiation
oncologist will compare the pre- and post-SabR contours to determine segmental collapse.
univariate and multivariate stepwise generalized estimating equation (Gee) analyses will be
conducted to identify significant factors contributing to BSS collapse, accounting for
intra-patient correlation within each nSCLC patient. The insights obtained from these
analyses will be used to formulate dose-thresholds for BSS segments. For each segment, we
will compute the probability of segmental collapse as a function of dose, Cs(D) and also
assign a weight [and] #955;s. This weight will be based on the findings of aim 2 and will be
proportional to the functional lung volume [Quote]served[Quote] by that segment. This
weighting scheme will ensure that the dose-thresholds (DT) are set more conservatively, i.e.,
with relatively lower Cs(DT) for the more critical BSS segments and vice versa.