A feasibility study of dynamic adaptive radiotherapy for nonsmall cell lung cancer

Kim, Min-Sun; Phillips, Mark H.

doi:10.1118/1.4945023

Cited by 4 publications

(8 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…If high doses are delivered to these organs at risk, the risk of complications may be increased. Adaptive planning may benefit these patients (5,(22)(23)(24). In our center, each CBCT image collected by every patient with atelectasis was evaluated.…”

Section: Right Lung As Ipsilateral Lungmentioning

confidence: 99%

Geometric and Dosimetric Changes in Tumor and Lung Tissue During Radiotherapy for Lung Cancer With Atelectasis

Chen

Shao

et al. 2021

Front. Oncol.

View full text Add to dashboard Cite

Background and PurposeThis article retrospectively characterized the geometric and dosimetric changes in target and normal tissues during radiotherapy for lung cancer patients with atelectasis.Materials and MethodsA total of 270 cone beam computed tomography (CBCT) scans of 18 lung patients with atelectasis were collected. The degree and time of resolution or expansion of the atelectasis were recorded. The geometric, dosimetric, and biological changes in the target and lung tissue were also quantified.ResultsThere were two patients with expansion, four patients with complete regression, six patients with partial regression, and six patients with no change. The time of resolution or expansion varied. The tumor volume increased by 3.8% in the first seven fractions, then decreased from the 9th fraction, and by 33.4% at the last CBCT. In the LR direction, the average center of mass (COM), boundaries of the tumors gradually shifted mediastinally. In the AP direction, the COM of the tumors was shifted slightly in the posterior direction and then gradually shifted to the anterior direction; the boundaries of the tumors all moved mediastinally. In the SI direction, the COM of the tumors on the right side of the body was substantially shifted toward the head direction. The boundaries of the tumors varied greatly. D2, D98, Dmean, V95, V107, and TCP of the PTV were reduced during radiotherapy and were reduced to their lowest values during the last two fractions. The volume of the ipsilateral lung tended to increase gradually. The V5, V10, V20, V30, V40, and NTCP of the total lung gradually increased with the fraction.ConclusionsFor most patients, regression of the atelectasis occurred, and the volume of the ipsilateral lung tended to increase while the tumor volume decreased, and the COM and boundary of the tumors shifted toward mediastinum, which caused an insufficient dose to the target and an overdose to the lungs. Regression or expansion may occur for any fraction, and it is therefore recommended that CBCT be performed at least every other day.

show abstract

Section: Right Lung As Ipsilateral Lungmentioning

confidence: 99%

Geometric and Dosimetric Changes in Tumor and Lung Tissue During Radiotherapy for Lung Cancer With Atelectasis

Chen

Shao

et al. 2021

Front. Oncol.

View full text Add to dashboard Cite

show abstract

“…The dosimetric benefit of spatiotemporally non-uniform fractionation schemes has been investigated recently in the papers (Unkelbach, Zeng, and Engelsman 2013; Unkelbach 2015; Unkelbach and Papp 2015), which solve a BED-based multi-fraction fluence map optimization problem to obtain treatment plans that deliver distinct dose distributions in different fractions. Spatiotemporally modulated radiotherapy has also been investigated in the papers (Kim, Ghate, and Phillips 2009; Kim, Stewart, and Phillips 2015; Kim and Phillips 2016; Saberian, Ghate, and Kim 2017), which optimize fractionation schedules based on a linear-quadratic cell survival model. The paper (Kim, Ghate, and Phillips 2012) formulates the treatment planning problem as a discrete-time stochastic control problem using functional imaging to observe the system state and using beam intensities as controls.…”

Section: Introductionmentioning

confidence: 99%

“…The dosimetric benefit of spatiotemporally non-uniform fractionation schemes has been investigated recently in the papers [9][10][11], which solve a BED-based multi-fraction fluence map optimization problem to obtain treatment plans that deliver distinct dose distributions in different fractions. Spatiotemporally modulated radiotherapy has also been investigated in the papers [12][13][14][15], which optimize fractionation schedules based on a linear-quadratic cell survival model. However, in these studies, the treatment plans are optimized using the same set of beams or VMAT arcs in all fractions, and the idea of fraction-variant beam angle selection is not considered.…”

Section: Introductionmentioning

confidence: 99%

“…distributions in different fractions. Spatiotemporally modulated radiotherapy has also been investigated in the papers (Kim et al 2009, Kim and Phillips 2016, Saberian et al 2017, which optimize fractionation schedules based on a linear-quadratic cell survival model. The paper (Kim et al 2012b) formulates the treatment planning problem as a discrete-time stochastic control problem using functional imaging to observe the system state and using beam intensities as controls.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Fraction-variant beam orientation optimization for non-coplanar IMRT

O’Connor

Nguyen

et al. 2018

Phys. Med. Biol.

View full text Add to dashboard Cite

Conventional beam orientation optimization (BOO) algorithms for IMRT assume that the same set of beam angles is used for all treatment fractions. In this paper we present a BOO formulation based on group sparsity that simultaneously optimizes non-coplanar beam angles for all fractions, yielding a fraction-variant (FV) treatment plan. Beam angles are selected by solving a multi-fraction fluence map optimization problem involving 500-700 candidate beams per fraction, with an additional group sparsity term that encourages most candidate beams to be inactive. The optimization problem is solved using the fast iterative shrinkage-thresholding algorithm. Our FV BOO algorithm is used to create five-fraction treatment plans for digital phantom, prostate, and lung cases as well as a 30-fraction plan for a head and neck case. A homogeneous PTV dose coverage is maintained in all fractions. The treatment plans are compared with fraction-invariant plans that use a fixed set of beam angles for all fractions. The FV plans reduced OAR mean dose and D values on average by 3.3% and 3.8% of the prescription dose, respectively. Notably, mean OAR dose was reduced by 14.3% of prescription dose (rectum), 11.6% (penile bulb), 10.7% (seminal vesicle), 5.5% (right femur), 3.5% (bladder), 4.0% (normal left lung), 15.5% (cochleas), and 5.2% (chiasm). D was reduced by 14.9% of prescription dose (right femur), 8.2% (penile bulb), 12.7% (proximal bronchus), 4.1% (normal left lung), 15.2% (cochleas), 10.1% (orbits), 9.1% (chiasm), 8.7% (brainstem), and 7.1% (parotids). Meanwhile, PTV homogeneity defined as D /D improved from .92 to .95 (digital phantom), from .95 to .98 (prostate case), and from .94 to .97 (lung case), and remained constant for the head and neck case. Moreover, the FV plans are dosimetrically similar to conventional plans that use twice as many beams per fraction. Thus, FV BOO offers the potential to reduce delivery time for non-coplanar IMRT.

show abstract

“…Another recent direction of theoretical research on the spatiobiologically integrated side focuses on adaptive planning of fluence-maps (Kim 2010, Ghate 2011, Kim and Phillips 2016, Saberian et al 2016. Unlike the traditional static-deterministic approach of adhering to a fluence-map that was calculated at the beginning of the treatment course, adaptive methods acknowledge that there is uncertainty in how tumors respond to radiation, and propose to recompute fluence-maps based on the observed evolution of the tumor's biological condition over multiple treatment sessions.…”

Section: Introductionmentioning

confidence: 99%

Adaptive treatment-length optimization in spatiobiologically integrated radiotherapy

2018

Self Cite

View full text Add to dashboard Cite

Recent theoretical research on spatiobiologically integrated radiotherapy has focused on optimization models that adapt fluence-maps to the evolution of tumor state, for example, cell densities, as observed in quantitative functional images acquired over the treatment course. We propose an optimization model that adapts the length of the treatment course as well as the fluence-maps to such imaged tumor state. Specifically, after observing the tumor cell densities at the beginning of a session, the treatment planner solves a group of convex optimization problems to determine an optimal number of remaining treatment sessions, and a corresponding optimal fluence-map for each of these sessions. The objective is to minimize the total number of tumor cells remaining (TNTCR) at the end of this proposed treatment course, subject to upper limits on the biologically effective dose delivered to the organs-at-risk. This fluence-map is administered in future sessions until the next image is available, and then the number of sessions and the fluence-map are re-optimized based on the latest cell density information. We demonstrate via computer simulations on five head-and-neck test cases that such adaptive treatment-length and fluence-map planning reduces the TNTCR and increases the biological effect on the tumor while employing shorter treatment courses, as compared to only adapting fluence-maps and using a pre-determined treatment course length based on one-size-fits-all guidelines.

show abstract

A feasibility study of dynamic adaptive radiotherapy for nonsmall cell lung cancer

Cited by 4 publications

References 43 publications

Geometric and Dosimetric Changes in Tumor and Lung Tissue During Radiotherapy for Lung Cancer With Atelectasis

Geometric and Dosimetric Changes in Tumor and Lung Tissue During Radiotherapy for Lung Cancer With Atelectasis

Fraction-variant beam orientation optimization for non-coplanar IMRT

Adaptive treatment-length optimization in spatiobiologically integrated radiotherapy

Contact Info

Product

Resources

About