The frequency of re-planning and its variability dependent on the modification of the re-planning criteria and IGRT correction strategy in head and neck IMRT

Stoll, Markus; Giske, Kristina; Debus, Jürgen; Bendl, Rolf; Stoiber, Eva Maria

doi:10.1186/1748-717x-9-175

Cited by 15 publications

(13 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For some patients receiving intensity‐modulated radiotherapy (IMRT) or volumetric‐modulated arc therapy (VMAT), the significant benefit of replanning has been demonstrated 4. The frequency of replanning in patients with head and neck cancer was reported to be 32%–70%, depending on criteria 5. It is challenging, however, to decide on the appropriate time for replanning.…”

Section: Introductionmentioning

confidence: 99%

“…Several investigators have looked for indicators to predict substantial dosimetric change. Although correlations between several parameters (such as weight loss, skin separation, and others) and dose change to target or organ at risk (OAR) were observed,4, 5, 6 no single parameter can be reliably used to decide the time of replanning for patients with head and neck cancer 4. Therefore, decisions on replanning are frequently based on the practical experience of clinicians.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Feasibility of CBCT‐based dose with a patient‐specific stepwise HU‐to‐density curve to determine time of replanning

Chen

Mutaf

et al. 2017

J Applied Clin Med Phys

View full text Add to dashboard Cite

Purpose(a) To investigate the accuracy of cone‐beam computed tomography (CBCT)–derived dose distributions relative to fanbeam–based simulation CT‐derived dose distributions; and (b) to study the feasibility of CBCT dosimetry for guiding the appropriateness of replanning.Methods and materialsImage data corresponding to 40 patients (10 head and neck [HN], 10 lung, 10 pancreas, 10 pelvis) who underwent radiation therapy were randomly selected. Each patient had both intensity‐modulated radiation therapy and volumetric‐modulated arc therapy plans; these 80 plans were subsequently recomputed on the CBCT images using a patient‐specific stepwise curve (Hounsfield units‐to‐density). Planning target volumes (PTVs; D98%, D95%, D2%), mean dose, and V95% were compared between simulation‐CT–derived treatment plans and CBCT‐based plans. Gamma analyses were performed using criterion of 3%/3 mm for three dose zones (>90%, 70%~90%, and 30%~70% of maximum dose). CBCT‐derived doses were then used to evaluate the appropriateness of replanning decisions in 12 additional HN patients whose plans were previously revised during radiation therapy because of anatomic changes; replanning in these cases was guided by the conventional observed source‐to‐skin‐distance change‐derived approach.ResultsFor all disease sites, the difference in PTV mean dose was 0.1% ± 1.1%, D2% was 0.7% ± 0.1%, D95% was 0.2% ± 1.1%, D98% was 0.2% ± 1.0%, and V95% was 0.3% ± 0.8%; For 3D dose comparison, 99.0% ± 1.9%, 97.6% ± 4.4%, and 95.3% ± 6.0% of points passed the 3%/3 mm criterion of gamma analysis in high‐, medium‐, and low‐dose zones, respectively. The CBCT images achieved comparable dose distributions. In the 12 previously replanned 12 HN patients, CBCT‐based dose predicted well changes in PTV D2% (Pearson linear correlation coefficient = 0.93; P < 0.001). If 3% of change is used as the replanning criteria, 7/12 patients could avoid replanning.Conclusions CBCT‐based dose calculations produced accuracy comparable to that of simulation CT. CBCT‐based dosimetry can guide the decision to replan during the course of treatment.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Feasibility of CBCT‐based dose with a patient‐specific stepwise HU‐to‐density curve to determine time of replanning

Chen

Mutaf

et al. 2017

J Applied Clin Med Phys

View full text Add to dashboard Cite

show abstract

“…Schwarz et al 15 analyzed patients with head-and-neck cancer and stated that even with good image guidance and daily 16 First work has been done with special fast replanning strategies by Li et al 17 Also radiation concepts by daily choosing the best plan from a precalculated plan library show promising results. 18,19 However, it remains an open question which strategy is the best.…”

Section: Discussionmentioning

confidence: 99%

Changes in Gross Tumor Volume and Organ Motion Analysis During Neoadjuvant Radiochemotherapy in Patients With Locally Advanced Pancreatic Cancer Using an In-House Analysis System

Kessel

Jäger

Habermehl

et al. 2015

Technol Cancer Res Treat

Self Cite

View full text Add to dashboard Cite

Background and Purpose: During radiation treatment, movement of the target and organs at risks as well as tumor response can significantly influence dose distribution. This is highly relevant in patients with pancreatic cancer, where organs at risk lie in close proximity to the target. Material and Methods: Data sets of 10 patients with locally advanced pancreatic cancer were evaluated. Gross tumor volume deformation was analyzed. Dose changes to organs at risk were determined with focus on kidneys both without adaptive radiotherapy compensation and with replanning based on weekly acquired computed tomography scans. Results: During irradiation, gross tumor volume changes between 0% and 26% and moves within a radius of 5 to 16 mm. Required maximal dose to organs at risk for kidneys can be met with the current practice of matching computed tomography scans during treatment and adjusting patient position accordingly. Comparison of the mean doses and V 15 , V 20 volumes demonstrated that weekly replanning could bring a significant dose sparing of the left kidney. Conclusion: Manual matching with focus on bony structures can lead to overall acceptable positioning of patients during treatment. Thus, tolerance doses of organs at risk, such as the kidneys, can be met. With adequate margins, normal tissue constraints to organs at risk can be kept as well. Adaptive radiotherapy approaches (in this case with weekly rescanning) reduced dose to organs at risk, which may be especially important for hypofractionated approaches.

show abstract

“…The considerable anatomical changes during the course of radiotherapy may lead to suboptimal dosimetry. Several factors have been reported to predict the need for replanning [8] [9] [13] [14] [15]. However, the optimal timing for replanning is poorly understood.…”

Section: Discussionmentioning

confidence: 99%

Usability of Deformable Image Registration for Adaptive Radiotherapy in Head and Neck Cancer and an Automatic Prediction of Replanning

Tanooka¹,

Doi²,

Ishida³

et al. 2017

IJMPCERO

View full text Add to dashboard Cite

Deformable image registration (DIR) has been an important component in adaptive radiotherapy (ART). Our goal was to examine the accuracy of ART using the dice similarity coefficient (DSC) and to determine the optimal timing of replanning. A total of 22 patients who underwent volume modulated arc therapy (VMAT) for head and neck (H&N) cancers were prospectively analyzed. The planning target volume (PTV) was to receive a total of 70 Gy in 33 fractions. A second planning CT scan (rescan) was performed at the 15th fraction. The DSC was calculated for each structure on both CT scans. The continuous variables to predict the need for replanning were assessed. The optimal cut-off value was determined using receiver operating characteristic (ROC) curve analysis. In the correlation between body weight loss and DSC of each structure, weight loss correlated negatively with DSC of the whole face (r s = −0.45) and the face surface (r s = −0.51). Patients who required replanning tended to have experienced rapid weight loss. The threshold DSC was 0.98 and 0.60 in the whole face and the face surface, respectively. Patients who showed low DSC in the whole face and the face surface required replanning at a significantly high rate (P < 0.05 and P < 0.01). Weight loss correlated with DSC in both the whole face and the face surface (P < 0.05 and P < 0.05). The DSC values in the face predicted the need for replanning. In addition, weight loss tended to correlate with DSC. DIR during ART was found to be a useful tool for replanning.

show abstract

The frequency of re-planning and its variability dependent on the modification of the re-planning criteria and IGRT correction strategy in head and neck IMRT

Cited by 15 publications

References 19 publications

Feasibility of CBCT‐based dose with a patient‐specific stepwise HU‐to‐density curve to determine time of replanning

Feasibility of CBCT‐based dose with a patient‐specific stepwise HU‐to‐density curve to determine time of replanning

Changes in Gross Tumor Volume and Organ Motion Analysis During Neoadjuvant Radiochemotherapy in Patients With Locally Advanced Pancreatic Cancer Using an In-House Analysis System

Usability of Deformable Image Registration for Adaptive Radiotherapy in Head and Neck Cancer and an Automatic Prediction of Replanning

Contact Info

Product

Resources

About