Dosimetric comparison of organs at risk in 5 different radiotherapy plans in patients with preoperatively irradiated rectal cancer

Abstract Background:Radiotherapy requires the target area and the organs at risk to be contoured on the CT image of the patient. During the process of organs-at-Risk (OAR) of the chest and abdomen, the doctor needs to contour at each CT image. The delineations of large and varied shapes are time-consuming and laborious.This study aims to evaluate the results of two automatic contouring software on OAR definition of CT images of lung cancer and rectal cancer patients. Methods: The CT images of 15 patients with rectal cancer and 15 patients with lung cancer were selected separately, and the organs at risk were outlined by the same experienced doctor as references, and then the same datasets were automatically contoured based on AiContour®© (Manufactured by Linking MED, China) and Raystation®© (Manufactured by Raysearch, Sweden) respectively. Overlap index (OI), Dice similarity index (DSC) and Volume difference (DV) were evaluated based on the auto-contours, and independent-sample t-test analysis is applied to the results. Results: The results of AiContour®© on OI and DSC were better than that of Raystation®© with statistical difference. There was no significant difference in DV between the results of two software. Conclusions: With AiContour®©, auto-contouring results of most organs in the chest and abdomen are good, and with slight modification, it can meet the clinical requirements for planning. With Raystation®©, auto-contouring results in most OAR is not as good as AiContour®©, and only the auto-contouring results of some organs can be used clinically after modification.

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PO-1121 Characterizing Dosimetric Uncertainties to Tumour Volume and Organs at Risk in Rectal Cancer

Radiotherapy and Oncology ◽

10.1016/s0167-8140(19)31541-5 ◽

2019 ◽

Vol 133 ◽

pp. S622-S623

Author(s):

O. Babatunde ◽

S. O’Cathail ◽

R. Cooke ◽

B. George ◽

M. Robinson ◽

...

Keyword(s):

At Risk ◽

Rectal Cancer ◽

Organs At Risk ◽

Tumour Volume

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Intensity-modulated radiation therapy (IMRT): Differences in target volumes and improvement in clinically relevant doses to small bowel in rectal carcinoma.

Journal of Clinical Oncology ◽

10.1200/jco.2011.29.4_suppl.586 ◽

2011 ◽

Vol 29 (4_suppl) ◽

pp. 586-586

Author(s):

H. Mok ◽

C. H. Crane ◽

T. Briere ◽

S. Beddar ◽

M. E. Delclos ◽

...

Keyword(s):

At Risk ◽

Rectal Cancer ◽

Radiation Therapy ◽

Small Bowel ◽

Rectal Carcinoma ◽

Organs At Risk ◽

Intensity Modulated Radiation Therapy ◽

Preoperative Treatment ◽

Conformal Radiation Therapy ◽

Intensity Modulated

586 Background: In the treatment of rectal cancer, a strong dose-volume relationship exists between the amount of small bowel receiving low- to intermediate-doses of radiation and the rates of acute, severe gastrointestinal toxicity. Highly conformal treatment approaches, such as intensity-modulated radiation therapy (IMRT), may reduce dose to adjacent organs-at-risk (OAR). We performed a dosimetric evaluation of IMRT compared to 3-dimensional conformal radiation therapy (3DCRT) in standard, preoperative treatment for rectal cancer. Methods: Using RTOG consensus contouring atlas, treatment volumes were generated for ten patients treated preoperatively, with IMRT plans compared to 3DCRT plans derived from classic anatomic landmarks, as well as modified 3DCRT plans treating the RTOG consensus volume. The patients were all T3, were node-negative (N=1) or node–positive (N=9), and were planned to a total dose of 45-Gy. Bowel displacement was achieved using a carbon-fiber bellyboard apparatus with prone positioning. Results: IMRT plans had superior PTV coverage, dose homogeneity, and conformality in treatment of the gross disease and at-risk nodal volume, in comparison to 3DCRT. Additionally, in comparison to the modified 3DCRT plans, IMRT achieved a concomitant reduction in doses to the bowel, bladder, pelvic bones, and femoral heads, with an improvement in absolute volumes of small bowel receiving dose levels known to induce clinically-relevant acute toxicity. In the six patients with the highest volume of small bowel (range: 209-537-cc), the volume of bowel receiving 15-Gy was reduced from a median of 224-cc in the modified 3DCRT plans to 185-cc with IMRT. Also, the IMRT volumes were typically larger than that covered by classic 3DCRT fields, without incurring penalty with respect to adjacent OAR. Conclusions: For rectal carcinoma, IMRT, compared to 3DCRT, yielded plans with superior target coverage, homogeneity, and conformality, while lowering dose to adjacent OAR. This is despite treating larger volumes, raising the possibility of a clinically-relevant improvement in the therapeutic ratio through the use of IMRT with a belly-board apparatus. No significant financial relationships to disclose.

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Implementation of HybridArc treatment technique in preoperative radiotherapy of rectal cancer: dose patterns in target lesions and organs at risk as compared to helical Tomotherapy and RapidArc

Radiation Oncology ◽

10.1186/1748-717x-7-120 ◽

2012 ◽

Vol 7 (1) ◽

Cited By ~ 10

Author(s):

Thierry Gevaert ◽

Benedikt Engels ◽

Cristina Garibaldi ◽

Dirk Verellen ◽

Peter Deconinck ◽

...

Keyword(s):

At Risk ◽

Rectal Cancer ◽

Helical Tomotherapy ◽

Preoperative Radiotherapy ◽

Organs At Risk ◽

Treatment Technique

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Volumetric and dosimetric comparison of organs at risk between the prone and supine positions in postoperative radiotherapy for prostate cancer

Radiation Oncology ◽

10.1186/s13014-018-1023-0 ◽

2018 ◽

Vol 13 (1) ◽

Cited By ~ 2

Author(s):

Subaru Sawayanagi ◽

Hideomi Yamashita ◽

Mami Ogita ◽

Tomoki Kiritoshi ◽

Takahiro Nakamoto ◽

...

Keyword(s):

Prostate Cancer ◽

At Risk ◽

Organs At Risk ◽

Postoperative Radiotherapy ◽

Dosimetric Comparison

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SU-E-P-51: Dosimetric Comparison to Organs at Risk Sparing Using Volumetric-Modulated Arc Therapy Versus Intensity-Modulated Radiotherapy in Postoperative Radiotherapy of Left-Sided Breast Cancer

Medical Physics ◽

10.1118/1.4923985 ◽

2015 ◽

Vol 42 (6Part5) ◽

pp. 3238-3238 ◽

Cited By ~ 1

Author(s):

L Qiao ◽

J Xie ◽

J Cheng ◽

N Liang ◽

G Deng ◽

...

Keyword(s):

Breast Cancer ◽

At Risk ◽

Organs At Risk ◽

Postoperative Radiotherapy ◽

Volumetric Modulated Arc Therapy ◽

Intensity Modulated Radiotherapy ◽

Dosimetric Comparison ◽

Intensity Modulated ◽

Arc Therapy

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Automatic segmentation of the clinical target volume and organs at risk in the planning CT for rectal cancer using deep dilated convolutional neural networks

Medical Physics ◽

10.1002/mp.12602 ◽

2017 ◽

Vol 44 (12) ◽

pp. 6377-6389 ◽

Cited By ~ 85

Author(s):

Kuo Men ◽

Jianrong Dai ◽

Yexiong Li

Keyword(s):

Neural Networks ◽

At Risk ◽

Rectal Cancer ◽

Convolutional Neural Networks ◽

Clinical Target Volume ◽

Organs At Risk ◽

Automatic Segmentation ◽

Target Volume ◽

Planning Ct

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Pediatric craniospinal irradiation with a short partial-arc VMAT technique for medulloblastoma tumors in dosimetric comparison

Radiation Oncology ◽

10.1186/s13014-020-01690-5 ◽

2020 ◽

Vol 15 (1) ◽

Author(s):

Gerhard Pollul ◽

Tilman Bostel ◽

Sascha Grossmann ◽

Sati Akbaba ◽

Heiko Karle ◽

...

Keyword(s):

At Risk ◽

Low Dose ◽

Organs At Risk ◽

Treatment Plan ◽

Volumetric Modulated Arc Therapy ◽

Conformal Radiotherapy ◽

Dosimetric Comparison ◽

Pediatric Medulloblastoma ◽

Treatment Plans ◽

3D Crt

Abstract Background This study aimed to contrast four different irradiation methods for pediatric medulloblastoma tumors in a dosimetric comparison regarding planning target volume (PTV) coverage and sparing of organs at risk (OARs). Methods In sum 24 treatment plans for 6 pediatric patients were realized. Besides the clinical standard of a 3D-conformal radiotherapy (3D-CRT) treatment plan taken as a reference, volumetric modulated arc therapy (VMAT) treatment plans (“VMAT_AVD” vs. “noAVD” vs. “FullArc”) were optimized and calculated for each patient. For the thoracic and abdominal region, the short partial-arc VMAT_AVD technique uses an arc setup with reduced arc-length by 100°, using posterior and lateral beam entries. The noAVD uses a half 180° (posterior to lateral directions) and the FullArc uses a full 360° arc setup arrangement. The prescription dose was set to 35.2 Gy. Results We identified a more conformal dose coverage for PTVs and a better sparing of OARs with used VMAT methods. For VMAT_AVD mean dose reductions in organs at risk can be realized, from 16 to 6.6 Gy, from 27.1 to 8.7 Gy and from 8.0 to 1.9 Gy for the heart, the thyroid and the gonads respectively, compared to the 3D-CRT treatment method. In addition we have found out a superiority of VMAT_AVD compared to the noAVD and FullArc trials with lower exposure to low-dose radiation to the lungs and breasts. Conclusions With the short partial-arc VMAT_AVD technique, dose exposures to radiosensitive OARS like the heart, the thyroid or the gonads can be reduced and therefore, maybe the occurrence of late sequelae is less likely. Furthermore the PTV conformity is increased. The advantages of the VMAT_AVD have to be weighed against the potentially risks induced by an increased low dose exposure compared to the 3D-CRT method.

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