scholarly journals Improving interinstitutional and intertechnology consistency of pulmonary SBRT by dose prescription to the mean internal target volume dose

2021 ◽  
Author(s):  
L. Wilke ◽  
C. Moustakis ◽  
O. Blanck ◽  
D. Albers ◽  
C. Albrecht ◽  
...  
Keyword(s):  
At Risk ◽  
Organs At Risk ◽  
Target Volume ◽  
Dose Fractionation ◽  
Internal Target ◽  
Internal Target Volume ◽  
Planning Study ◽  
Dose Distributions ◽  
Significant Difference ◽  
The Mean

Abstract Purpose Dose, fractionation, normalization and the dose profile inside the target volume vary substantially in pulmonary stereotactic body radiotherapy (SBRT) between different institutions and SBRT technologies. Published planning studies have shown large variations of the mean dose in planning target volume (PTV) and gross tumor volume (GTV) or internal target volume (ITV) when dose prescription is performed to the PTV covering isodose. This planning study investigated whether dose prescription to the mean dose of the ITV improves consistency in pulmonary SBRT dose distributions. Materials and methods This was a multi-institutional planning study by the German Society of Radiation Oncology (DEGRO) working group Radiosurgery and Stereotactic Radiotherapy. CT images and structures of ITV, PTV and all relevant organs at risk (OAR) for two patients with early stage non-small cell lung cancer (NSCLC) were distributed to all participating institutions. Each institute created a treatment plan with the technique commonly used in the institute for lung SBRT. The specified dose fractionation was 3 × 21.5 Gy normalized to the mean ITV dose. Additional dose objectives for target volumes and OAR were provided. Results In all, 52 plans from 25 institutions were included in this analysis: 8 robotic radiosurgery (RRS), 34 intensity-modulated (MOD), and 10 3D-conformal (3D) radiation therapy plans. The distribution of the mean dose in the PTV did not differ significantly between the two patients (median 56.9 Gy vs 56.6 Gy). There was only a small difference between the techniques, with RRS having the lowest mean PTV dose with a median of 55.9 Gy followed by MOD plans with 56.7 Gy and 3D plans with 57.4 Gy having the highest. For the different organs at risk no significant difference between the techniques could be found. Conclusions This planning study pointed out that multiparameter dose prescription including normalization on the mean ITV dose in combination with detailed objectives for the PTV and ITV achieve consistent dose distributions for peripheral lung tumors in combination with an ITV concept between different delivery techniques and across institutions.

scholarly journals Dosimetric Comparison of Intraoperative Radiotherapy and SRS for Liver Metastases

2021 ◽  
Vol 11 ◽  
Author(s):  
Davide Scafa ◽  
Thomas Muedder ◽  
Jasmin A. Holz ◽  
David Koch ◽  
Younéss Nour ◽  
...  
Keyword(s):  
Liver Metastases ◽  
Organs At Risk ◽  
Liver Volume ◽  
Intraoperative Radiotherapy ◽  
Target Volume ◽  
Breath Hold ◽  
Internal Target Volume ◽  
Deep Inspiration Breath Hold ◽  
Dosimetric Comparison ◽  
The Mean

Purpose/ObjectivesTo perform a dosimetric comparison between kilovoltage intraoperative radiotherapy (IORT) and stereotactic radiosurgery (SRS) simulating both deep-inspiration breath-hold (DIBH) and free-breathing (FB) modalities for patients with liver metastases.Methods/MaterialsDiagnostic computed tomographies (CT) of patients carrying one or two lesions <4 cm and who underwent surgery were retrospectively screened and randomly selected for the study. For DIBH-SRS, a gross target volume (GTV) plus planning target volume (PTV) were delineated. For FB-SRS, a GTV plus an internal target volume (ITV) and PTV were defined. Accounting for the maximal GTV diameters, a modified GTV (GTV-IORT) was expanded circumferentially to simulate a resection cavity. The best suitable round-applicator size was thereafter selected. All treatment plans were calculated homogeneously to deliver 40 Gy. Doses delivered to organs at risk (OAR) and target volumes were compared for IORT vs. both SRS modalities.ResultsEight patients encompassing 10 lesions were included in the study. The mean liver volume was 2,050.97 cm3 (SD, 650.82), and the mean GTV volume was 12.23 cm3 (SD, 12.62). As for target structures, GTV-IORT [19.44 cm3 (SD, 17.26)] were significantly smaller than both PTV DIBH-SRS [30.74 cm3 (SD, 24.64), p = 0.002] and PTV FB-SRS [75.82 cm3 (SD, 45.65), p = 0.002]. The median applicator size was 3 cm (1.5–4.5), and the mean IORT simulated delivery time was 45.45 min (SD, 19.88). All constraints were met in all modalities. Liver V9.1 showed significantly smaller volumes with IORT [63.39 cm3 (SD, 35.67)] when compared to DIBH-SRS [150.12 cm3 (SD, 81.43), p = 0.002] or FB-SRS [306.13 cm3 (SD, 128.75), p = 0.002]. No other statistical or dosimetrically relevant difference was observed for stomach, spinal cord, or biliary tract. Mean IORT D90 was 85.3% (SD, 6.05), whereas D95 for DIBH-SRS and FB-SRS were 99.03% (SD, 1.71; p = 0.042) and 98.04% (SD, 3.46; p = 0.036), respectively.ConclusionKilovoltage IORT bears the potential as novel add-on treatment for resectable liver metastases, significantly reducing healthy liver exposure to radiation in comparison to SRS. Prospective clinical evidence is required to confirm this hypothesis.

Comparative dosimetry of brachytherapy treatment planning between a volume-based plan by CT and a point-based plan by TAUS in CT datasets for brachytherapy

2021 ◽  
pp. 1-8
Author(s):  
Chaiyaporn Pintakham ◽  
Ekkasit Tharavichitkul ◽  
Somsak Wanwilairat ◽  
Wannapha Nobnop
Keyword(s):  
At Risk ◽  
Treatment Planning ◽  
Sigmoid Colon ◽  
Clinical Target Volume ◽  
Organs At Risk ◽  
Target Volume ◽  
Reference Points ◽  
Uterine Perforation ◽  
Target Dose ◽  
The Mean

Abstract Aim: To evaluate comparative dosimetry of brachytherapy treatment planning between a volume-based plan by computed tomography (CT) and a point-based plan by transabdominal ultrasound (TAUS) in CT datasets for brachytherapy. Materials and methods: From 2019 to 2021, 59 different datasets of CT images were collected from 38 patients treated by intracavitary brachytherapy with tandem ovoid or tandem ring applicators. At that time, TAUS was performed to prevent uterine perforation and to evaluate topography of the cervix during application. In volume-based planning by CT, the target dose was used to keep the dose at 90% of high-risk clinical target volume (HR-CTV), to give a dose of at least 7Gy, while in the point-based plan by TAUS, the target dose was used to keep the minimum dose to eight cervix reference points (measured by TAUS), to give a dose of at least 7Gy. The doses to targets and organs at risk were evaluated and compared between volume-based planning by CT and the point-based plan by TAUS. Results: Of 59 fractions, a tandem ovoid applicator was used in 48 fractions (81·3%). In the volume-based plan by CT, the mean doses to HR-CTV(D90), intermediate-risk clinical target volume (IR-CTV)(D90), bladder(D2cc), rectum(D2cc) and sigmoid colon(D2cc) were 7·0, 3·9, 4·9, 2·9 and 3·3 Gy, respectively, while in the point-based plan by TAUS, the mean doses to HR-CTV(D90), IR-CTV(D90), bladder(D2cc), rectum(D2cc) and sigmoid colon(D2cc) were 8·2, 4·6, 5·9, 3·4 and 3·9 Gy, respectively. The percentages of mean dose differences between TAUS and CT of HR-CTV(D90), IR-CTV(D90), bladder(D2cc), rectum(D2cc) and sigmoid colon(D2cc) were 17·7, 19·5, 20·5, 19·5, 21·3 and 19·8%, respectively. With the target dose to the point-based plan by TAUS (7 Gy to the cervix reference points), this was close to D98 of HR-CTV with a mean percentage of difference of 0·6%. Findings: The point-based plan by TAUS showed higher values to targets and organs at risk than the volume-based plan by CT. With the point-based plan by TAUS, it was close to D98 of HR-CTV.

scholarly journals Comparative study between Acuros XB algorithm and Anisotropic Analytical Algorithm in the case of heterogeneity for the treatment of lung cancer

2018 ◽  
Vol 24 (3) ◽  
pp. 115-119
Author(s):  
Mohammed El Adnani Krabch ◽  
Abdelouahed Chetaine ◽  
Abdelati Nourreddine ◽  
Fatim Zohra Er-Radi ◽  
Laila Baddouh
Keyword(s):  
Lung Cancer ◽  
At Risk ◽  
Heterogeneous Media ◽  
Maximum Dose ◽  
Organs At Risk ◽  
Target Volume ◽  
Conformity Index ◽  
Acuros Xb ◽  
Significant Difference ◽  
The Impact

Abstract The aim of this study was to investigate the impact of heterogeneity on the dose calculation for two algorithms implemented in the TPS “Analytical Anisotropic Algorithm (AAA) and Acuros XB” and validated the use of Acuros XB algorithm in clinical routine. First, we compare the dose calculated by these algorithms and the dose measured at the given point P, which is found after heterogeneity insert. Second, we extend our work on clinical cases that present a complex heterogeneity. By evaluating the impact of the choice of the algorithm on the dose coverage of the tumor, and the dose received by the organs at risk for 20 patients affected by lung cancer. The result of our phantom study showed a good agreement with several studies that showed the superiority of the Acuros XB over the AAA in predicting dose when it concerns heterogeneous media. The treatment plans for 20 lung cancers were calculated by two algorithms AAA and Acuros XB, the results show a statistical significant difference between algorithms for Homogeneity Index and the maximum dose of planning target volume (HI: 0.11±0.01 vs 0.05±0.01 p = 0.04; Dmax: 69.30±3.12 vs 68.51±2.64 p = 0.02). Instead, no statistically significant difference was observed for conformity index CI and mean dose (CI: 0.98±0.18 vs 0.99±0.14 p = 0.33; Dmean: 66.3±0.65 vs 66.10 ±0.61 p = 0.54). For organs at risk, the maximum dose for spinal cord, mean dose and D37 % of lung minus GTV (dose receiving 37% of lung volume) were found to be lower for AAA plans than Acuros XB and the differences were statistically significant (p<0.05). For the heart D33% and D67% were found to be higher for AAA plans than Acuros XB and the differences were statistically significant (p<0.05), but No difference was observed for D100% of the heart. The use of the AXB algorithm is suitable in the case of presence of heterogeneity, because it allows to have a better accuracy close to the Monte Carlo calculation.

Comparison of image-based three-dimensional treatment planning using AcurosTM BV and AAPM TG-43 algorithm for intracavitary brachytherapy of carcinoma cervix

2016 ◽  
Vol 15 (3) ◽  
pp. 254-262 ◽  
Author(s):  
Mourougan Sinnatamby ◽  
Vivekanandan Nagarajan ◽  
K S. Reddy ◽  
Gunaseelan Karunanidhi ◽  
Vivekanandam Singhavajala
Keyword(s):  
Treatment Planning ◽  
Organs At Risk ◽  
Three Dimensional ◽  
Tumour Volume ◽  
Target Volume ◽  
Mean Value ◽  
Intracavitary Brachytherapy ◽  
Carcinoma Cervix ◽  
Significant Difference ◽  
The Mean

AbstractAimTo compare the image-based three-dimensional treatment planning using AcurosTM BV and AAPM TG-43 algorithm for intracavitary brachytherapy of carcinoma cervix.Materials and methodsTwenty-seven patients with cancer cervix, stage IIB or IIIB with vaginal involvement limited to the upper third of the vagina was included into the study. Intracavitary treatments with the patient in this study done with computed tomography and magnetic resonance imaging compatible ring applicator. Groupe European de Curietherapie and European Society for Therapeutic Radiology and Oncology recommended doses to target volumes and organs at risk compared using dose volume histogram.ResultsThe mean value of Point ‘A’ dose was compared between AcurosTM BV and TG-43, which indicates 0·13% difference. The differences in the mean dose to gross tumour volume for various volumes are V100% 0·28%, V150% 1·22% and V200% 1·03%; all volumes showed small difference but statistical significant (p<0·05). The mean dose of high-risk clinical target volume (HRCTV) D90 using AcurosTM BV was 8·47 Gy, which was 1·63% less compared with TG-43. The mean point A dose using AcurosTM BV is 1·04 times the dose to D90 of mean HRCTV. The same difference was observed in comparison with TG43. D2cc and D0·1cc of the bladder, rectum and sigmoid showed a statistically significant difference (p<0·05) in comparison with TG-43.ConclusionThe differences in dosimetric parameters between the AcurosTM BV and TG-43 proved to be statistically significant. The difference is very small, and they are clinically insignificant.

scholarly journals Comparison of two planning techniques (FiF/IMRT) for postoperative radiation therapy of prostate cancer

2020 ◽  
Vol 48 (2-3) ◽  
pp. 47-53
Author(s):  
Nevena Obajdin ◽  
Keyword(s):  
Prostate Cancer ◽  
At Risk ◽  
Radiation Therapy ◽  
Organs At Risk ◽  
Planning Techniques ◽  
Dose Distributions ◽  
Dose Volume ◽  
Significant Difference ◽  
Target Volumes ◽  
Planning Technique

Introduction: Within the past two decades, we made significant progress in radiation therapy for prostate cancer. At UH Rijeka IMRT became the technique of choice for radiation therapy following radical prostatectomy since 2016. Previously, an advanced 3-DCRT technique using the field-in-field (FiF) method was used for dose distribution optimization around target volumes and organs-at-risk. This research has been performed to investigate the influence of planning technique choice (FiF or IMRT) on coverage of target volumes with prescribed dose and organs-at-risk sparing. Materials and methods: Comparison of dose distributions calculated using FiF and IMRT techniques was performed retrospectively for ten patients who underwent postoperative radiotherapy. The prescribed dose for all patients was delivered using IMRT, and for this research, we also calculated dose distributions using the FiF technique. For FiF and IMRT techniques, we used linear accelerator photon beams. To determine the influence of planning technique on dose distribution parameters related to target volumes (GTV, CTV, PTV1, PTV2) were analyzed. For organs-at-risk sparing evaluation (rectum, bladder, femoral heads), we used dose-volume constraints. Results and discussion: The analysis of parameters related to target volumes has shown that most of them had no statistically significant difference (V100%(GTV), V100%(CTV), V95%(PTV2), V95%(PTV1)). For both planning techniques, internationally set dose constraints were achieved. Statistically, we found a significant difference for V100%(PTV2), p=0,000534, and V100%(PTV1), p=0,042944 in favor of IMRT. A statistically significant difference (p=0,045966) was found for the volume of the rectum, which receives 40Gy, and for the volume of femoral heads, which receives 30Gy (p=0,000385), where the sparing is better for IMRT. For dose-volume constraints related to the bladder, no statistically significant differences were found. Conclusion: Results of this research show a statistically significant difference for V100% target volume coverage for PTV1 and PTV2, with better dose coverage accomplished by IMRT. Concerning organs-at-risk sparing, a statistically significant difference in favor of IMRT was found for rectum volume, which receives 40Gy. Expectedly, IMRT was superior to the FiF technique. However, differences between the two planning techniques were relatively small, which points to the fact that the FiF technique is viable as a technique of choice.

scholarly journals Doses to Organs at Risk Calculated Using Plato and Oncentra Softwares in Intracavitary Brachytherapy

2021 ◽  
Vol 19 (01) ◽  
pp. 117-126
Author(s):  
NOR HAFIZAH ABDULLAH ◽  
REDUAN ABDULLAH ◽  
MAZURAWATI MOHAMAD ◽  
AHMAD ZAKARIA ◽  
CHIANG CHEN SUK
Keyword(s):  
At Risk ◽  
Treatment Planning ◽  
Organs At Risk ◽  
Intracavitary Brachytherapy ◽  
Planning Systems ◽  
Organ Doses ◽  
Independent Verification ◽  
Treatment Planning Systems ◽  
Significant Difference ◽  
The Mean

This is a retrospective study, the organ doses to the bladder and rectum were compared between Nucletron PLATO V14.2.3 (BV) and newer version software Oncentra MasterPlan V4.3 (OMP) treatment planning systems (TPS). The treatment data of 32 intracavitary brachytherapy patients at Hospital Universiti Sains Malaysia from January 2010 to June 2015 were used. These data sets were used for catheter reconstruction for both PLATO and OMP TPS followed by independent verification using Excel. There is no significant difference in mean doses to organs at risk (OARs) that calculated by both TPS (p>0.05). The mean percentage of doses calculated by PLATO TPS for bladder and rectum were 66.58 ± 27.42 % and 46.27 ± 14.47 % respectively. While the mean percentage of doses for bladder and rectum calculated by OMP TPS were 65.68 ± 24.24 % and 46.46 ± 16.66 respectively. The mean percentage difference in doses comparison between independent verification calculation and PLATO TPS was 1.96 ± 6.00% and then became 6.37 ± 5.17% when it was compared with OMP TPS. Overall, the dose calculation differences for both versions of TPS were within the range recommended by Nuclear Regulatory Commission (NRC). The dose calculations of the two treatment planning systems showed good agreement and both could be used in planning intracavitary brachytherapy for cervical cancer. Whereas Excel based independent verification suitable to be implemented as routine dose verification programme prior to treatment delivery.

Non-coplanar VMAT improves plan quality for locoregional radiotherapy of left-sided breast cancer with internal mammary nodes

2020 ◽  
Author(s):  
Yuan Xu ◽  
Pan Ma ◽  
Zhihu Hu ◽  
Yuan Tian ◽  
Kuo Men ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Organs At Risk ◽  
Left Lung ◽  
Breast Conserving Surgery ◽  
Target Volume ◽  
Conformity Index ◽  
Internal Mammary Nodes ◽  
Significant Difference ◽  
Internal Mammary ◽  
The Mean

Abstract Purpose A planning study was performed to evaluate the feasibility of non-coplanar volume modulated arc therapy (ncVMAT) for locoregional radiotherapy of left-sided breast cancer with internal mammary nodes. Methods and materials Ten patients with left-sided breast cancer after breast conserving surgery were retrospectively studied. The planning target volumes (PTV) were contoured encompassing the whole breast/chestwall, internal mammary nodes (IMN) and supraclavicular nodal (SCN) region. For each patient, ncVMAT plan with 4 partial arcs composing of two coplanar arcs and two non-coplanar arcs with couch rotating to 90˚ was generated. The prescription dose was normalized to cover 95% of PTV with 50 Gy delivering in 25 fractions. For each ncVMAT plan, dosimetric parameters were compared with coplanar VMAT (coVMAT) plan optimizing with identical coplanar beam angle arrangement. Results With ncVMAT, the mean conformity index of the whole PTV increased from 0.82±0.02 to 0.86±0.01 (p=0.005), and there was no significant difference for the homogeneity index. The mean coverage of internal mammary target volume (PTVimn) with ncVMAT increased from 88.77±3.07% to 91.67±3.84% comparing with coVMAT (p=0.005). Meanwhile, the V55 in PTVscn and PTVimn decreased significantly from 5.76±6.03%, 13.73±7.77% to 2.94±3.93%, 3.75±3.36%, separately (p<0.01). For organs at risk, the average V30, V20, V10, V5 and Dmean of heart decreased from 5.13±3.22%, 12.18±7.29%, 33.98±15.73%, 72.03±16.79% and 10.47±2.97 Gy to 4.86±2.54%, 9.35±5.43%, 25.16±12.42%, 62.27±13.18% and 9.08±2.34 Gy, separately (p<0.01). Furthermore, ncVMAT significantly reduced the mean V20, V10, V5, Dmean of left lung, and V10, V5, Dmean of contralateral lung (p<0.01). A better sparing of LAD descending coronary artery and right breast were also shown with ncVMAT (p<0.01). Conclusions Compared to coVMAT, ncVMAT provides better conformity, lower V55 in PTVscn and PTVimn, better coverage of PTVimn, better dose sparing in heart, bilateral lung, LAD and right breast for locoregional radiotherapy of left-sided breast cancer with internal mammary nodes, which potentially increase the local control in IMN and reduce the risk of deleterious effects.

scholarly journals Automatic Segmentation of Clinical Target Volume and Organs-At-Risk for Breast Conservative Radiotherapy Using a Convolutional Neural Network

2021 ◽  
Author(s):  
Zhikai Liu ◽  
Fangjie Liu ◽  
Wanqi Chen ◽  
Yinjie Tao ◽  
Xia Liu ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Spinal Cord ◽  
At Risk ◽  
Clinical Target Volume ◽  
Organs At Risk ◽  
Target Volume ◽  
Contralateral Breast ◽  
Dice Similarity Coefficient ◽  
Proposed Model ◽  
The Mean

Abstract Background and Objective: Delineation of the clinical target volume (CTV) and organs at risk (OARs) is very important for radiotherapy but is time-consuming and prone to inter- and intra-observer variation. We trained and evaluated a U-Net-based model to provide fast and consistent auto-segmentation for breast cancer radiotherapy. Methods: We collected 160 patients’ computed tomography (CT) scans with early-stage breast cancer who underwent breast-conserving surgery (BCS) and were treated with radiotherapy in our center. CTV and OARs (contralateral breast, heart, lungs and spinal cord) were delineated manually by two experienced radiation oncologists. The data were used for model training and testing. The dice similarity coefficient (DSC) and 95th Hausdorff distance (95HD) were used to assess the performance of our model. CTV and OARs were randomly selected as ground truth (GT) masks, and artificial intelligence (AI) masks were generated by the proposed model. The contours were randomly distributed to two clinicians to compare CTV score differences. The consistency between two clinicians was tested. We also evaluated time cost for auto-delineation. Results: The mean DSC values of the proposed method were 0.94, 0.95, 0.94, 0.96, 0.96 and 0.93 for breast CTV, contralateral breast, heart, right lung, left lung and spinal cord, respectively. The mean 95HD values were 4.31 mm, 3.59 mm, 4.86 mm, 3.18 mm, 2.79 mm and 4.37 mm for the above structures respectively. The average CTV scores for AI and GT were 2.92 versus 2.89 when evaluated by oncologist A (P=.612), and 2.75 versus 2.83 by oncologist B (P=.213), with no statistically significant differences. The consistency between two clinicians was poor (Kappa=0.282). The times for auto-segmentation of CTV and OARs were 3.88 s and 6.15 s. Conclusions: Our proposed model can improve the speed and accuracy of delineation compared with U-Net, while it performed equally well with the segmentation generated by oncologists.

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