Daily Online Cone Beam Computed Tomography to Assess Interfractional Motion in Patients With Intact Cervical Cancer

Tyagi, Neelam; Lewis, John H.; Yashar, Catheryn M.; Vo, Daniel; Jiang, Steve B; Mundt, Arno J.; Mell, Loren K.

doi:10.1016/j.ijrobp.2010.06.003

Cited by 68 publications

(54 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Future work addressing the contribution of these anatomic considerations is warranted. Prior studies have shown regression in tumor and target volumes with time (14,15,20), but we found that time did not predict coverage likelihood. Assuming that tumor regression does not lead to increased mobility of the uterus and cervix, it should not affect coverage.…”

Section: Discussioncontrasting

confidence: 91%

“…However, daily CBCT scans have been used successfully in prior studies (20)(21)(22), and this technology is currently the most widely available option for daily online image guidance and soft tissue imaging. Despite some variability in scan quality, CTV delineation was in most cases straightforward.…”

Section: Discussionmentioning

confidence: 99%

“…Several groups have investigated interfractional and intrafractional cervical motion during radiation treatment and have reported relatively large movements (14)(15)(16)(17)(18)(19)(20)(21)(22)(23). However, prior studies have generally been retrospective, involving less than daily online imaging and relatively small sample sizes, whereas well-powered studies to validate various proposed models independently and prospectively have been lacking.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Prospective Validation of a High-Dimensional Shape Model for Organ Motion in Intact Cervical Cancer

Williamson

Green

Noticewala

et al. 2016

International Journal of Radiation Oncology*Biology*Physics

View full text Add to dashboard Cite

SummaryWe sought to validate a strategy for planning target volume definition in patients with intact cervical cancer, based on a previously published shape model. Using daily cone beam computed tomography imaging from patients treated with intensity modulated radiation therapy, we found that 92.3% of target volumes were entirely encompassed within the 95% isodose structure, which was not significantly lower than our hypothesized probability of 95.0% (PZ.19). Therefore, we consider this expansion strategy to be valid.Purpose: Validated models are needed to justify strategies to define planning target volumes (PTVs) for intact cervical cancer used in clinical practice. Our objective was to independently validate a previously published shape model, using data collected prospectively from clinical trials. Methods and Materials: We analyzed 42 patients with intact cervical cancer treated with daily fractionated pelvic intensity modulated radiation therapy and concurrent chemotherapy in one of 2 prospective clinical trials. We collected online cone beam computed tomography (CBCT) scans before each fraction. Clinical target volume (CTV) structures from the planning computed tomography scan were cast onto each CBCT scan after rigid registration and manually redrawn to account for organ motion and deformation. We applied the 95% isodose cloud from the planning computed tomography scan to each CBCT scan and computed any CTV outside the 95% isodose cloud. The primary aim was to determine the proportion of CTVs that were encompassed within the 95% isodose volume. A 1-sample t test was used to test the hypothesis that the probability of complete coverage was different from 95%. We used mixed-effects logistic regression to assess effects of time and patient variability. Results: The 95% isodose line completely encompassed 92.3% of all CTVs (95% confidence interval, 88.3%-96.4%), not significantly different from the 95% probability anticipated a priori (PZ.19). The overall proportion of missed CTVs was small: the grand mean of covered CTVs was 99.9%, and 95.2% of misses were located in the anterior body of the uterus. Time did not affect coverage probability (PZ.71). definition strategy based on a shape model for intact cervical cancer, the probability of CTV coverage was high and the volume of CTV missed was low. This PTV expansion strategy is acceptable for clinical trials and practice; however, we recommend daily image guidance to avoid systematic large misses in select patients. Ó

show abstract

Section: Discussioncontrasting

confidence: 91%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Prospective Validation of a High-Dimensional Shape Model for Organ Motion in Intact Cervical Cancer

Williamson

Green

Noticewala

et al. 2016

International Journal of Radiation Oncology*Biology*Physics

View full text Add to dashboard Cite

show abstract

“…In this study, we found that a uniform margin of 10 mm failed to encompass the vagina in 17.3 and 18.1% of the fractions on lines A and B, respectively. However, this encompassment rate appeared to be higher compared with that of intact cervical cancer (33) and the vaginal apex postoperatively (31). For intact cervical cancer, a uniform margin of 10 mm reportedly failed to encompass the CTV in 59% of the fractions and failed to encompass the cervix and fundus in 36 and 54% of the fractions, respectively (33).…”

Section: Discussionmentioning

confidence: 88%

An assessment of interfractional bladder, rectum and vagina motion in postoperative cervical cancer based on daily cone-beam computed tomography

Wang

et al. 2015

Molecular and Clinical Oncology

View full text Add to dashboard Cite

Abstract. Interfractional variations of the bladder, rectum and vagina may affect the accuracy of postoperative intensity-modulated radiotherapy in patients with cervical cancer. This study aimed to assess the interfractional variations with daily kV cone-beam computed tomography (CBCT). All the patients were instructed to control the filling status of the bladder and rectum. CBCT images were obtained daily after set-up and the bladder, rectum and vagina were contoured on each CBCT scan. All the contours were transferred to the planning CT following image fusion. Interfractional variations in pelvic organs were assessed with CBCT based on two reference lines, which were identified as A (the midsaggital line across the superior border of pubic symphysis) and B (a parallel line 1.5 cm above line A). The mean volume (range) of the bladder and rectum was 156.5 (1.7-626.5) and 48.2 (11.3-139.7) ml, respectively. The uniform planning target volume (PTV) margin of 10 mm failed to encompass the vagina in 17.3 and 18.1% of the fractions on lines A and B, respectively. The motion of the vagina (standard deviation) was 0.3 (0.3) and 0.1 (0.5) cm on lines A and B, respectively. The anteroposterior dimension and position of the vagina were significantly affected by the filling status of the bladder (P<0.05), but not by that of the rectum. Although instructions were given, the interfractional variations of the vagina and other pelvic organs were significant, which may exceed the uniform PTV margin; therefore, more effective methods to decrease these variations should be investigated.

show abstract

“…Complicating this is the highly individualized tumor regression that occurs during treatment, which in turn can influence tumor and normal tissue coverage [13][14][15][16][17] . While several groups have investigated inter-fraction motion for this tumor site using 3-dimensional imaging and proposed a variety of margin recipes, it remains to be seen whether a class solution PTV margin is appropriate 13,[18][19][20][21] . More individualized PTV margin strategies such as creating an internal target volume (ITV) using a bladder full/bladder empty technique or selecting from a library of plans based on the different bladder volumes have also been investigated 22 .…”

Section: Mesorectal Nodes Of ≥ 5mm Diameter On Mrimentioning

confidence: 99%

Variability in Clinical Target Volume Delineation for Intensity Modulated Radiotherapy in Three Challenging Cervix Cancer Scenarios

Lim

Fyles

Portelance

et al. 2010

International Journal of Radiation Oncology*Biology*Physics

View full text Add to dashboard Cite

Purpose/Objective(s)-The purpose of this study was to assess variability in contouring the gross tumor volume (GTV) and clinical target volume (CTV) of three clinical cervix cancer cases Address for Correspondence: Anthony Fyles, MD, FRCPC, Radiation Medicine Program, Princess Margaret Hospital, 610 University Ave, Toronto, Ontario, Canada M5G 2M9, Phone: 416-946-6522, Fax: 416-946-2111, ; Email: Anthony.Fyles@rmp.uhn.on.ca Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. by a cohort of international experts in the field, in preparation for the development of an online teaching atlas. Conflicts of Interest: none HHS Public AccessMethods and Materials-Twelve international experts participated. Three clinical scenarios: node positivity (PLN), retroverted uterus (RV) and parametrial invasion (PI) were used. Sagittal and axial MR images of the clinical cases were downloaded to participants' treatment planning systems for contouring. The GTV/cervix/uterus/parametria/vagina and nodal CTV were contoured. Contours' consensus was assessed for sensitivity/specificity using an expectation maximization algorithm called Simultaneous Truth and Performance Level Estimation (STAPLE) and overall experts' agreement was summarized by kappa statistics.Results-Agreement for GTV in the three clinical cases was high (STAPLE sensitivity 0.54-0.92; specificity 0.97-0.98; kappa measure for PLN, RV and PI was 0.86, 0.76 and 0.42; p<0.0001).Moderate to substantial agreement was seen for nodal CTV (kappa statistics for PLN, RV and PI was 0.65, 0.58 and 0.62; p<0.0001), uterus (kappa for PLN, RV and PI was 0.45, 0.74 and 0.77; p<0.0001) and parametria (kappa for PLN, RV and PI was 0.49, 0.62 and 0.50; p<0.0001).Contouring heterogeneity was greatest for the cervix (kappa measure for PLN, RV and PI was 0.15, 0.4 and 0.24; p<0.0001) and vagina (kappa for PLN, RV and PI was 0.47, 0.36 and 0.46; <0.0001), reflecting difficulties in determining the interface between GTV and these tissues.Conclusion-Kappa statistics of the different CTV components generally demonstrated moderate to substantial agreement among international experts in the field of gynecological radiotherapy. Further planning target volume (PTV) margins accounting for organ motion and setup errors are a necessary addition to the CTV.

show abstract

Daily Online Cone Beam Computed Tomography to Assess Interfractional Motion in Patients With Intact Cervical Cancer

Cited by 68 publications

References 20 publications

Prospective Validation of a High-Dimensional Shape Model for Organ Motion in Intact Cervical Cancer

Prospective Validation of a High-Dimensional Shape Model for Organ Motion in Intact Cervical Cancer

An assessment of interfractional bladder, rectum and vagina motion in postoperative cervical cancer based on daily cone-beam computed tomography

Variability in Clinical Target Volume Delineation for Intensity Modulated Radiotherapy in Three Challenging Cervix Cancer Scenarios

Contact Info

Product

Resources

About