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

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.

Treatment planning for non-small cell lung tumours: VMAT versus 3DCRT a quantitative dosimetric study

2019 ◽  
Vol 19 (4) ◽  
pp. 327-332
Author(s):  
Ahmed Hadj Henni ◽  
Yann Lauzin ◽  
Nicolas Pirault ◽  
Brian Dubos ◽  
Maximilien Roge ◽  
...  
Keyword(s):  
At Risk ◽  
Organs At Risk ◽  
Treatment Plan ◽  
Volumetric Modulated Arc Therapy ◽  
Conformal Radiotherapy ◽  
Target Volume ◽  
Low Doses ◽  
Heart Volume ◽  
Dosimetric Study ◽  
Mean Lung Dose

AbstractPurpose:The dosimetric impact of volumetric modulated arc therapy (VMAT) in lung cancer compared with 3D conformal radiotherapy (3DCRT) is well known. However, this improvement is often associated with an increase in low doses. The aim of this study is to quantify these results more accurately.Methods:For each patient treated with 3DCRT, a second VMAT treatment plan was calculated. Usual dosimetric parameters such as target coverage or dose to the organs at risk were used to achieve the comparisons.Results:For planning target volume, homogeneity and conformity indices showed superiority of VMAT (respectively 0·07 and 0·87) compared to 3DCRT (0·11 and 0·57). For spinal cord planning organ at risk volume, the median maximum dose was 45·6 Gy in 3DCRT against 19·3 Gy in VMAT. Heart volume receiving at least 35 Gy (V35) decreased from 15·64% in 3DCRT to 8·28% in VMAT. Oesophagus V50 was higher in 3DCRT (25·45%) than in VMAT (14·03%). The mean lung dose was 17·9 Gy in 3DCRT versus 15·5 Gy in VMAT. Moreover, volumes receiving 5, 10 and 15 Gy were not significantly different between the two techniques when VMAT was performed with partial arcs.Conclusion:All the dosimetric parameters were improved with VMAT compared to the 3DCRT without increasing low doses when using partial arcs.

scholarly journals Clinical Validation and Treatment Plan Evaluation Based on Auto-Delineation of the Clinical Target Volume for Prostate Cancer Radiotherapy

2022 ◽  
Author(s):  
Jing Shen ◽  
Yinjie TAO ◽  
Hui GUAN ◽  
Hongnan ZHEN ◽  
Lei HE ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
At Risk ◽  
Organs At Risk ◽  
Treatment Plan ◽  
Statistical Significance ◽  
Locally Advanced ◽  
Target Volume ◽  
Ct Scans ◽  
Dice Similarity Coefficient ◽  
Treatment Plans

Abstract Purpose Clinical target volumes (CTV) and organs at risk (OAR) could be auto-contoured to save workload. The goal of this study was to assess a convolutional neural network (CNN) for totally automatic and accurate CTV and OAR in prostate cancer, while also comparing anticipated treatment plans based on auto-contouring CTV to clinical plans. Methods From January 2013 to January 2019, 217 computed tomography (CT) scans of patients with locally advanced prostate cancer treated at our hospital were collected and analyzed. CTV and OAR were delineated with a deep learning based method, which named CUNet. The performance of this strategy was evaluated using the mean Dice similarity coefficient (DSC), 95th percentile Hausdorff distance (95HD), and subjective evaluation. Treatment plans were graded using predetermined evaluation criteria, and % errors for clinical doses to the planned target volume (PTV) and organs at risk(OARs) were calculated. Results The defined CTVs had mean DSC and 95HD values of 0.84 and 5.04 mm, respectively. For one patient's CT scans, the average delineation time was less than 15 seconds. When CTV outlines from CUNetwere blindly chosen and compared to GT, the overall positive rate in clinicians A and B was 53.15% vs 46.85%, and 54.05% vs 45.95%, respectively (P>0.05), demonstrating that our deep machine learning model performed as good as or better than human demarcation Furthermore, 8 testing patients were chosen at random to design the predicted plan based on the auto-courtoring CTV and OAR, demonstrating acceptable agreement with the clinical plan: average absolute dose differences of D2, D50, D98, Dmean for PTV are within 0.74%, and average absolute volume differences of V45, V50 for OARs are within 3.4%. Without statistical significance (p>0.05), the projected findings are comparable to clinical truth. Conclusion The experimental results show that the CTV and OARs defined by CUNet for prostate cancer were quite close to the ground reality.CUNet has the potential to cut radiation oncologists' contouring time in half. When compared to clinical plans, the differences between estimated doses to CTV and OAR based on auto-courtoring were small, with no statistical significance, indicating that treatment planning for prostate cancer based on auto-courtoring has potential.

Dosimetric comparison of 3-dimensional conformal radiotherapy (3D-CRT) and volumetric-modulated arc therapy (VMAT) in locally advanced cancer cervix

2020 ◽  
pp. 1-8
Author(s):  
Animesh Agrawal ◽  
Rahat Hadi ◽  
Satyajeet Rath ◽  
Avinav Bharati ◽  
Madhup Rastogi ◽  
...  
Keyword(s):  
De Novo ◽  
Abdominal Cavity ◽  
Locally Advanced ◽  
Volumetric Modulated Arc Therapy ◽  
Conformal Radiotherapy ◽  
Target Volume ◽  
Conformity Index ◽  
Dosimetric Comparison ◽  
Arc Therapy ◽  
3D Crt

Abstract Introduction: Dosimetric advantages of volumetric-modulated arc therapy (VMAT) over three-dimensional conformal radiotherapy (3D-CRT) are not established in a head-on comparison of a uniform group of locally advanced carcinoma of the cervix (LACC). Therefore, we conducted a dosimetric comparison of these two techniques in LACC patients. Materials and methods: Computed tomography (CT) data of histologically proven de novo LACC, including Stage IIB–IIIB and earlier stages deemed inoperable, were included in this prospective observational dosimetric study. Planning was initially done by 3D-CRT technique (dose of 45–50·4 Gy @ 1·8–2 Gy/# was used in the actual treatment), followed by VMAT planning and appropriate dosimetric comparisons were done in 39 cases. Results: For planning target volume coverage, D95, D98 and D100 (p < 0·0001 for all parameters) and V95 and V100 (p = 0·002 and <0·0001, respectively) were significantly improved with VMAT. The conformity index (CI) was significantly better with VMAT (p = 0·03), while 3D-CRT had a significantly better homogeneity index (HI)(p = 0·003). Dose to the urinary bladder was significantly reduced with VMAT compared to 3D-CRT for V20–V50, except V10. The doses to the rectum and abdominal cavity were significantly reduced with VMAT compared to 3D-CRT plans for all parameters (V10–V50). The number of organs at risks (OARs) for which constraints were met was higher with VMAT plans than with 3D-CRT plans, with at least four out of the five OARs protected in 46·1 versus 5·1% and all constraints achieved in 15·4% versus none. Conclusion: We conclude that in dosimetric terms, VMAT is superior to 3D-CRT for LACC.

Volumetric modulated arc therapy versus 3D conformal radiotherapy for selected childhood neoplasms

2014 ◽  
Vol 14 (1) ◽  
pp. 35-42 ◽  
Author(s):  
Marzanna Chojnacka ◽  
Anna Zygmuntowicz-Piętka ◽  
Anna Semaniak ◽  
Katarzyna Pędziwiatr ◽  
Ryszard Dąbrowski ◽  
...  
Keyword(s):  
At Risk ◽  
Organs At Risk ◽  
Volumetric Modulated Arc Therapy ◽  
Conformal Radiotherapy ◽  
Target Volume ◽  
High Dose ◽  
Dose Volume Histograms ◽  
Dose Volume ◽  
Arc Therapy ◽  
Childhood Neoplasms

AbstractAimThe comparative study of the plan quality between volumetric modulated arc therapy (VMAT) and 3D conformal therapy (3DCRT) for the treatment of selected representative childhood neoplasms was performed.Materials and methodsDuring the year 2013, 44 children with neoplasms were irradiated using VMAT. The 3DCRT plans were created retrospectively and compared with the VMAT plans for four tumour locations. The conformity parameters, dose volume histograms for target volume and organs at risk, number of monitor units and time used to deliver the single fraction were evaluated and compared for each plan. Additionally, for patients with brain tumour the comparison of different arcs configuration was made.ResultsVMAT modality presented the superiority over older conformal methods with regard to the improvement in the dose conformity and normal tissue sparing. The noncoplanar arcs arrangement was beneficial in the decrease of high-dose volume and the protection of the organs at risk located oppositely to the target volume.FindingsVMAT could be preferred technique for treating childhood neoplasms, especially when the complex-shaped target volume is localised close to the critical structures. The noncoplanar arcs arrangement could be the method of choice in the reirradiated patients and in these with laterally located brain tumours.

Comparing treatment plans for stomach cancer: three-dimensional conformal radiotherapy (3D-CRT), physical wedge-based conformal RT (WB-CRT) and intensity-modulated radiotherapy (IMRT)

2021 ◽  
pp. 1-6
Author(s):  
Gokcen Inan ◽  
Osman Vefa Gul
Keyword(s):  
Spinal Cord ◽  
Stomach Cancer ◽  
Organs At Risk ◽  
Left Kidney ◽  
Three Dimensional ◽  
Conformal Radiotherapy ◽  
Conformity Index ◽  
Intensity Modulated ◽  
Treatment Plans ◽  
3D Crt

Abstract Objective: The aim of this study was to find the optimal radiotherapy (RT) method using three-dimensional (3D) conformal RT (CRT), physical wedge-based CRT (WB-CRT) and dynamic intensity-modulated RT (D-IMRT) techniques for stomach cancer. Methods: Ten patients with gastric cancer were selected for this study. For each patient, three different treatment plans were generated. 3D-CRT, WB-CRT and IMRT plans were evaluated in terms of dosimetry. Treatment plans were compared with respect to the planning target volume and organs at risk (OARs) volumes including right and left kidney doses (V13, V20 and V28), heart mean and maximum doses, spinal cord maximum doses, dose homogeneity index, conformity index (CI), delivery time and the monitor unit counts for the treatment. Statistical analysis was performed using the SPSS (Statistical Package for the Social Sciences) v25.1 software (IBM Inc., Chicago, IL, USA). Results: In stomach plans, IMRT showed a significantly lower dose for the left and right kidneys than that of WB-CRT or 3D-CRT (p < 0·05). Compared with WB-CRT or 3D-CRT, IMRT reduced the V28, V20, V13 and mean dose to bilateral kidneys (p < 0·05). IMRT plans indicated better dosimetry for at the Dmean of the liver and heart. Concerning the calculated CI, values for IMRT plans gave significant results than other plans (p < 0·05). Conclusions: IMRT plans provided better protection for the kidneys, liver, heart and spinal cord. For the treatment of stomach cancer, considering the dose to the OARs, IMRT appears to be the most superior technique.

Preoperative chemoradiotherapy for locally advanced rectal adenocarcinoma: A dosimetric comparison of intensity-modulated radiation therapy (IMRT) with three-dimensional conformal radiotherapy (3D-CRT).

2011 ◽  
Vol 29 (4_suppl) ◽  
pp. 615-615
Author(s):  
C. T. Tao ◽  
L. M. Scala ◽  
H. Gee ◽  
D. Lim ◽  
B. Padilla ◽  
...  
Keyword(s):  
Small Bowel ◽  
Organs At Risk ◽  
Locally Advanced ◽  
Rectal Adenocarcinoma ◽  
Conformal Radiotherapy ◽  
Preoperative Chemoradiotherapy ◽  
Dosimetric Comparison ◽  
Pelvic Malignancies ◽  
Femoral Heads ◽  
3D Crt

615 Background: Small bowel and bladder toxicities (bleeding, obstruction, perforation, and stricture) are rare but serious late complications of pelvic radiotherapy (RT) related to dose received by these organs. IMRT has been used effectively in other pelvic malignancies (prostate and gynecologic) to decrease the dose to normal tissues when compared to 3D-CRT. Few studies have examined the use of IMRT in rectal cancer to assess whether a similar dose reduction is feasible. Methods: Eight consecutively treated patients with T2/T3 and N0/N1 rectal adenocarcinoma underwent 5-FU based neoadjuvant chemo-RT using 7-field sliding-window IMRT between 2008 and 2010. Retrospectively, conventional 4-field 3D-CRT plans were generated for dosimetric comparison with IMRT treatment plans. Planning target volumes included the gross tumor, rectum, peri-rectal tissues, pre-sacral space, and common and internal iliac lymphatics. Organs at risk included small bowel (contoured as all small bowel identified on the planning CT plus a 1 cm symmetrical expansion), bladder, and femoral heads. Small bowel, bladder, and femoral head mean doses and volumes receiving 45 Gy (V45) were compared between conventional and IMRT plans, respectively. Paired Student's t-test was used for statistical analysis. Results: Mean prescription dose was 52.9 ± 3.3 Gy. Compared to 3D-CRT, IMRT plans had an 11% lower mean dose delivered to the bladder (38.2 ± 4.5 Gy vs 43.1 ± 1.9 Gy, p = 0.028) and 24% lower mean dose to the small bowel (24.0 ± 2.9 Gy vs 31.7 ± 7.7 Gy, p = 0.014). IMRT plans also had a 55% lower bladder V45 (27 ± 19% vs 61 ± 22%, p = 0.0077) and a 96% lower small bowel V45 (1 ± 0% vs 21± 20%, p = 0.021). The femoral heads received a nonsignificant higher mean dose (19.2 ± 3.9 Gy vs 16.6 ± 3.0 Gy, p = 0.069). Conclusions: Small bowel and bladder volume receiving 45 Gy and mean dose were significantly lower using IMRT compared with 3D-CRT planning. More stringent volumetric planning constraints may be necessary to further reduce the dose to the femoral heads. Further study is warranted to examine the clinical benefit of these dosimetric findings. No significant financial relationships to disclose.

scholarly journals Hybrid volumetric modulated arc therapy for hypofractionated radiotherapy of breast cancer: a treatment planning study

2020 ◽  
Author(s):  
Alexander Venjakob ◽  
Michael Oertel ◽  
Dominik Alexander Hering ◽  
Christos Moustakis ◽  
Uwe Haverkamp ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Negative Impact ◽  
Organs At Risk ◽  
Volumetric Modulated Arc Therapy ◽  
Breath Hold ◽  
Deep Inspiration Breath Hold ◽  
Mixed Beam ◽  
Arc Therapy ◽  
Treatment Plans ◽  
3D Crt

Abstract Purpose This study aims to evaluate the best possible practice using hybrid volumetric modulated arc therapy (H-VMAT) for hypofractionated radiation therapy of breast cancer. Different combinations of H‑VMAT—a combination of three-dimensional radiotherapy (3D-CRT) and VMAT—were analyzed regarding planning target volume (PTV), dose coverage, and exposure to organs at risk (OAR). Methods Planning computed tomography scans were acquired in deep-inspiration breath-hold. A total of 520 treatment plans were calculated and evaluated for 40 patients, comprising six different H‑VMAT plans and a 3D-CRT plan as reference. H‑VMAT plans consisted of two treatment plans including 3D-CRT and VMAT. During H‑VMAT planning, the use of hard wedge filters (HWF) and beam energies were varied. The reference plans were planned with mixed beam energies and the inclusion/omission of HWF. Results Compared to the reference treatment plans, all H‑VMAT plans showed consistently better PTV dose coverage, conformity, and homogeneity. Additionally, OAR protection was significantly improved with several H‑VMAT combinations (p < 0.05). The comparison of different H‑VMAT combinations showed that inclusion of HWF in the base plan had a negative impact on PTV dose coverage, conformity, and OAR exposure. It also increased the planned monitor units and beam-on time. Advantages of using lower beam energies (6-MV photons) in both the base plan and in the VMAT supplementary dose were observed. Conclusion The H‑VMAT technique is an effective possibility for generating homogenous and conformal dose distributions. With the right choice of H‑VMAT combination, superior OAR protection is achieved compared to 3D-CRT.

scholarly journals Advantages of VMAT-IMRT technique in nasopharyngeal cancer

2016 ◽  
Vol 6 (22) ◽  
pp. 101-108
Author(s):  
Cristina Sanda ◽  
Codrut Sarafoleanu
Keyword(s):  
At Risk ◽  
Treatment Time ◽  
Organs At Risk ◽  
Treatment Plan ◽  
Volumetric Modulated Arc Therapy ◽  
Nasopharyngeal Cancer ◽  
Intensity Modulated Radiation Therapy ◽  
Concurrent Chemotherapy ◽  
Chemotherapy Treatment ◽  
Low Incidence

Abstract BACKGROUND. Radiotherapy, associated with chemotherapy, is the main method of treatment in both early and advanced stages of nasopharyngeal carcinoma. Intensity modulated radiation therapy (IMRT) provides high doses of radiation to the primary tumor, sparing the organs at risk. Volumetric modulated arc therapy (VMAT) is one of the most promising radiation methods which produces superior target coverage, improving the protection of organs at risk and reduces treatment time. MATERIAL AND METHODS. We performed a retrospective study on 30 patients diagnosed with nasopharyngeal cancer and admitted in “Sfanta Maria” Clinical Hospital between October 2012 and December 2014. All patients have undergone VMAT-IMRT associated with induction or concurrent chemotherapy. At the end of the treatment, patients were followed up at one, three and six months, and then every six months for 2 years. RESULTS. At the end of the radio-chemotherapy treatment, 27 patients (90%) had a complete tumor and lymphatic response and 3 of them (10%) presented a partial response. At the end of the follow-up period, we observed 5 patients with recurrences, including 2 deceased. CONCLUSION. VMAT-IMRT in association with chemotherapy treatment is well tolerated by patients. The good results reflected in high rates of cured patients, the low incidence of side effects, recommend this treatment plan as an optimal indication for nasopharyngeal tumors.

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