Impact of delineation uncertainties on dose to organs at risk in CT-guided intracavitary brachytherapy

Duane, F.; Langan, Brian; Gillham, Charles; Walsh, L.; Rangaswamy, Guhan; Lyons, C.; Dunne, Mary; Walker, Christopher; McArdle, O.

doi:10.1016/j.brachy.2013.08.010

Cited by 28 publications

(28 citation statements)

References 36 publications

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“…Not surprisingly, inter-observer studies on contouring variation demonstrate superior results for MRI-based delineation when compared with CT-based approach. 44, 51-54 Ultrasound and PET CT may add complementary information during delineation, but their role as eventual independent modality for contouring remains to be defined. In summary, TDM-guided applicator prototyping should be based on target volumes, delineated on MRI.…”

Section: Discussionmentioning

confidence: 99%

Virtual modelling of novel applicator prototypes for cervical cancer brachytherapy

Petrič

Hudej

Al-Hammadi

et al. 2016

Radiology and Oncology

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BackgroundStandard applicators for cervical cancer Brachytherapy (BT) do not always achieve acceptable balance between target volume and normal tissue irradiation. We aimed to develop an innovative method of Target-volume Density Mapping (TDM) for modelling of novel applicator prototypes with optimal coverage characteristics. Patients and methods. Development of Contour-Analysis Tool 2 (CAT-2) software for TDM generation was the core priority of our task group. Main requests regarding software functionalities were formulated and guided the coding process. Software validation and accuracy check was performed using phantom objects. Concepts and terms for standardized workflow of TDM post-processing and applicator development were introduced.ResultsCAT-2 enables applicator-based co-registration of Digital Imaging and Communications in Medicine (DICOM) structures from a sample of cases, generating a TDM with pooled contours in applicator-eye-view. Each TDM voxel is assigned a value, corresponding to the number of target contours encompassing that voxel. Values are converted to grey levels and transformed to DICOM image, which is transported to the treatment planning system. Iso-density contours (IDC) are generated as lines, connecting voxels with same grey levels. Residual Volume at Risk (RVR) is created for each IDC as potential volume that could contain organs at risk. Finally, standard and prototype applicators are applied on the TDM and virtual dose planning is performed. Dose volume histogram (DVH) parameters are recorded for individual IDC and RVR delineations and characteristic curves generated. Optimal applicator configuration is determined in an iterative manner based on comparison of characteristic curves, virtual implant complexities and isodose distributions.ConclusionsUsing the TDM approach, virtual applicator prototypes capable of conformal coverage of any target volume, can be modelled. Further systematic assessment, including studies on clinical feasibility, safety and effectiveness are needed before routine use of novel prototypes can be considered.

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Section: Discussionmentioning

confidence: 99%

Virtual modelling of novel applicator prototypes for cervical cancer brachytherapy

Petrič

Hudej

Al-Hammadi

et al. 2016

Radiology and Oncology

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“…2. PIBS, PIBS+2 cm, and PIBS-2 cm determined from sagittal MRI corresponding to BT treatment to the mean [25]. For each of the P = 5 patients (p) and each of the n = 5 observers (o), two dose measurements M = 2 (m) in each point (i) were carried out.…”

Section: Methodsmentioning

confidence: 99%

Inter-observer and intra-observer variability in reporting vaginal dose points for cervical cancer in high-dose-rate brachytherapy

Carrasco

Chimeno

Adria-Mora

et al. 2020

jcb

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Purpose: The ICRU 89 recommends reporting a set of vaginal dose points for cervical cancer treatments in order to quantify the goodness of implant. This vaginal dose reporting method for combined external beam radiotherapy and brachytherapy has been adopted by the EMBRACE II study protocol. Large variations in dose between patients and centers have been reported. The aim of this study was to determine possible discrepancies with consensus observers from the same institution. Therefore, the inter-and intra-observer variability were analyzed. Material and methods: For five patients, five experienced observers reported dose at the proposed vaginal points twice. The effect of inter-and intra-observer variations on total dose was analyzed by estimating biologically equivalent dose EQD 2 (α/β = 3 Gy). Coefficient of variation (CV) was used to provide a measure of data dispersion as a proportion to the mean. Results: The maximum inter-observer deviation among all patients and all points ranged from 0.5 Gy to 24.1 Gy in EQD 2. The higher inter-observer discrepancies were found at points at 3 o'clock and at 6 o'clock, with respect to ovoids. In case of the maximum intra-observer deviation, it ranged from 0.5 Gy to 14.2 Gy, with higher deviation points at 12 o'clock and 9 o'clock, with respect to ovoids. Conclusions: There is a need to ensure consistency in vaginal points reporting. The impact of the dosimetric inter-and intra-observer variability should also be considered when dealing with dose tolerances and limits due to the potential dose gradient.

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“…[20] Duane et al, in their study in eight patients, examined the reflection of uncertainties in OAR contours drawn by different individuals in the DVH parameter, respectively, 13.2% and 9% of the bladder and rectum D 2cm3 were determined. [21] In a study conducted by Saarnak et al, images of 10 patients were contoured by bladder and rectum volumes by three separate users, and the inter-user variability for D 2cm3 was 10% and 11% in the bladder and rectum, respectively. [22] Differences between D2cc and D0.1cc dose sum between DIR and rigid registration may be clinically significant, although the difference in OAR volumes is less than the variability of different individuals.…”

Section: Dir-based Contour Propagation In Gynecological Brtmentioning

confidence: 99%

Deformable Registration in Gynecologic Brachytherapy

Şenkesen¹

2019

TJ Oncol

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Advances in image and computer technologies have enabled the use of advanced techniques in the field of radiation oncology. Different imaging methods and/or data obtained by the same imaging method with different dates require registration process to the reference dataset. Deformable registration performs scaling and shearing movements as well as translation and rotation movements. Thus, the differences between the images are minimized, and the accuracy of the applications is increased. In recent years, 3D-image-based brachytherapy has become more common with the aim to register images for adaptive planning. In this step of the planning process, registration algorithms can provide time and convenience by automatically transferring the defined contours to the registered image. This review examines studies on the use of deformable registration methods in gynecological brachytherapy.

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Impact of delineation uncertainties on dose to organs at risk in CT-guided intracavitary brachytherapy

Cited by 28 publications

References 36 publications

Virtual modelling of novel applicator prototypes for cervical cancer brachytherapy

Virtual modelling of novel applicator prototypes for cervical cancer brachytherapy

Inter-observer and intra-observer variability in reporting vaginal dose points for cervical cancer in high-dose-rate brachytherapy

Deformable Registration in Gynecologic Brachytherapy

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