Challenges and Differences in External Radiation Therapy for Retinoblastoma: From Standard Techniques to New Developments

Aims The purpose of this study is to calculate the treatment plans and to compare the dose distributions and dose-volume histograms (DVH) for 6 external radiotherapy techniques for the treatment of retinoblastoma as well as intensity-modulated radiotherapy (IMRT) and fractionated stereotactic radiotherapy (Cyberknife). Methods Treatment plans were developed using 6 techniques, including an en face electron technique (ET), an anterior and lateral wedge photon technique (LFT), a 3D conformal (6 fields) technique (CRT), an inverse plan IMRT, tomotherapy, and conventional focal stereotactic external beam radiotherapy with Cyberknife (SBRT). Dose volume analyses were carried out for each technique. Results All techniques except electron provided similar target coverage. When comparing conformal plan with IMRT and SBRT, there was no significant difference in planning target volume dose distribution. The mean volume of ipsilateral bony orbit received more than 20 Gy, a suggested threshold for bone growth inhibition. The V20 Gy was 73% for the ET, 57% for the LFT, 87% for the CRT, 65% for the IMRT, 66% for the tomotherapy, and 2.7% for the SBRT. Conclusions This work supports the potential use of IMRT and SBRT to spare normal tissues in these patients.

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A comparison of proton and photon radiotherapy in reducing cardiac exposure for patients receiving radiation therapy for distal and esophagogastric junction cancer.

Journal of Clinical Oncology ◽

10.1200/jco.2014.32.3_suppl.167 ◽

2014 ◽

Vol 32 (3_suppl) ◽

pp. 167-167

Author(s):

Ted Chen-Tai Ling ◽

Jerry Monroe Slater ◽

Rachel Mifflin ◽

Prashanth Nookala ◽

Roger Grove ◽

...

Keyword(s):

Radiation Therapy ◽

Esophagogastric Junction ◽

Intensity Modulated Radiotherapy ◽

Target Volume ◽

Dose Distributions ◽

Dose Volume Histograms ◽

Dose Volume ◽

Partial Volumes ◽

Treatment Plans ◽

Adequate Coverage

167 Background: Recent studies indicate that radiation exposure to heart may have a greater impact on perioperative cardiac morbidities than do other clinical factors. The purpose of this study is to investigate dose distributions of proton and photon treatment plans in patients (pts) with distal and esophagogastric junction (GEJ) carcinoma, focusing specifically on dose reduction to cardiac structures. Methods: Ten pts between 2010 and 2013 were included in this study. Three separate plans were generated for each patient: 3D proton plan, 3D photon plan, and Intensity modulated radiotherapy (IMRT) photon plan. The clinical target volume (CTV) consisted of the pre-operative extent of tumor plus a 10mm manual expansion in all directions. The planning target volume (PTV) was generated by a further expansion on the CTV ranging from 10-15mm. A dose of 50.4Gy given in 28 fractions was delivered to the PTV. All plans were optimized to allow 90% isodose coverage of at least 95% of the PTV. Dose-volume histograms were calculated and analyzed in order to compare plans between the three modalities. ANOVA and two-tailed paired t-tests were performed for all data parameters. Results: The 3D proton plans showed decreased dose to partial volumes of the entire heart, arteries, valves, atria, and ventricles in comparison to both the IMRT and 3D photon plans (see Table). The IMRT plans showed decreased dose delivered to the LAD artery, pericardium, and atria in comparison to the 3D photon plans (see Table). Conclusions: For pts receiving radiation therapy for distal esophageal and GEJ cancer, proton plans are technically feasible with adequate coverage while resulting in lower dose to cardiac structures. This may result in decreased cardiac toxicity and less complications in a multimodality setting. [Table: see text]

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A dosimetric comparison of craniospinal irradiation using TomoDirect radiotherapy, TomoHelical radiotherapy and 3D conventional radiotherapy

Journal of Radiotherapy in Practice ◽

10.1017/s1460396917000309 ◽

2017 ◽

Vol 16 (4) ◽

pp. 391-402

Author(s):

Shirley W. S. Tsang ◽

Mark Collins ◽

Jacky T. L. Wong ◽

George Chiu

Keyword(s):

Organs At Risk ◽

Intensity Modulated Radiotherapy ◽

Conformal Radiotherapy ◽

Target Volume ◽

Craniospinal Irradiation ◽

Conventional Radiotherapy ◽

Biological Damage ◽

Dose Volume Histograms ◽

Normal Tissues ◽

Dose Volume

AbstractAimThe purpose of this study was to dosimetrically compare TomoDirect, TomoHelical and linear accelerator-based 3D-conformal radiotherapy (Linac-3DCRT) for craniospinal irradiation (CSI) in the treatment of medulloblastoma.MethodsFive CSI patients were replanned with Linac-3DCRT, TomoHelical, TomoDirect-3DCRT and TomoDirect-intensity-modulated radiotherapy (IMRT). Dose of 36 Gy in 20 fractions was prescribed to the planning target volume (PTV). Homogeneity index (HI), non-target integral dose (NTID), dose–volume histograms, organs-at-risk (OARs)Dmax,Dmeanand treatment times were compared.ResultsTomoHelical achieved the best PTV homogeneity compared with Linac-3DCRT, TomoDirect-3DCRT and TomoDirect-IMRT (HI of 3·6 versus 20·9, 8·7 and 9·4%, respectively). TomoDirect-IMRT achieved the lowest NTID compared with TomoDirect-3DCRT, TomoHelical and Linac-3DCRT (141 J versus 151 J, 181 J and 250 J), indicating least biological damage to normal tissues. TomoHelical plans achieved the lowestDmaxin all organs except the breasts, and lowestDmeanfor most OARs, except in laterally situated OARs, where TomoDirect triumphed. Beam-on time was longest for TomoHelical, followed by TomoDirect and Linac-3DCRT.FindingsTomoDirect has the potential to lower NTID and shorten treatment times compared with TomoHelical. It reduces PTV inhomogeneity and better spares OARs compared with Linac-3DCRT. Therefore, TomoDirect may be a CSI treatment alternative to TomoHelical and in place of Linac-3DCRT.

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Dosimetric and radiobiological comparison of external beam radiotherapy using simultaneous integrated boost technique for esophageal cancer in different location.

Journal of Clinical Oncology ◽

10.1200/jco.2019.37.15_suppl.e15505 ◽

2019 ◽

Vol 37 (15_suppl) ◽

pp. e15505-e15505

Author(s):

Lu Wang ◽

Jinming Yu

Keyword(s):

Esophageal Cancer ◽

External Beam Radiotherapy ◽

Intensity Modulated Radiotherapy ◽

Target Volume ◽

Simultaneous Integrated Boost ◽

Conformity Index ◽

Tumor Control ◽

Tumor Control Probability ◽

Integrated Boost ◽

Treatment Plans

e15505 Background: Based on dosimetry and radiobiology to compare treatment plans for esophageal cancer (EC) in different location using intensity modulated radiotherapy (IMRT), volumetric modulated arc radiotherapy (VMAT) and helical tomotherapy(HT) with simultaneous integrated boost (SIB) technique. Methods: A total of 20 patients including 5 cases respectively located in the cervix, upper, middle and lower thorax were generated for IMRT, VMAT and HT plans. The dose volume histogram statistics, conformity index (CI), homogeneity index (HI), tumor control probability (TCP) and normal tissues control probability (NTCP) were analyzed to evaluate treatment plans. Results: HT showed significantly improvement over IMRT and VMAT in terms of CI(0.93±0.03), HI(0.07±0.03) and TCP(88.08±0.82%) in cervical EC(p<0.05). IMRT greatly developed TCP(88.29±1.79%;85.11±0.79%), and offered superior CIs (0.87±0.04;0.90±0.01) and HIs(0.10±0.01; 0.06±0.01) compared with VMAT and HT in upper and middle thoracic EC(p<0.05). Meanwhile, the V30(33.30±6.49%), mean dose (2559.00±219.64cGy) and NTCP(0.50±0.61%) of heart for IMRT were significantly reduced than other two techniques in middle thoracic EC. Patients with lower thoracic EC yielded the similar CIs and HIs(all p>0.05) for the 3 techniques, but VMAT showed the lowest NTCP of lungs (0.01±0.01%) with improved TCP (84.84±1.13%). Conclusions: HT was a good option with little lung and heart involvement as it achieved superior dose conformality and uniformity. IMRT was a perfect strategy with large thoracic involvement. It significantly improved tumor local control and reduced heart dose and complications with acceptable dose to lungs. VMAT was preferred with a smaller target volume but surrounded by more heart and less lungs. Individually choosing optimal technique for EC in different location will be warranted.

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Dosimetry Analysis of Three Kinds of Radiation Technique for Postoperative Gastric Cancer

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.641-642.725 ◽

2013 ◽

Vol 641-642 ◽

pp. 725-731

Author(s):

Hua Tang ◽

Ju Dong Luo ◽

Xu Jing Lu ◽

Ling Chen ◽

Yan Ma ◽

...

Keyword(s):

Gastric Cancer ◽

Spinal Cord ◽

Treatment Planning ◽

Statistical Difference ◽

Intensity Modulated Radiotherapy ◽

Conformal Radiotherapy ◽

Target Volume ◽

Dose Volume Histograms ◽

Dose Volume ◽

Better Than

Objective: To compare dose-volume histograms (DVHs) and the dose distribution of three-dimensional conformal radiotherapy(3DCRT),7 fields radiotherapy(7FRT) and intensity-modulated radiotherapy (IMRT) of treatment planning in gastric cancer. Methods: We selected 5 patients with gastric cancer, they were pathologically confirmed stage T3,T4 or N+ gastric cancer. All patients underwent radical gastrectomy. A dosimetry study was carried out on these five patients. For each patient, three kinds of treatment planning were designed with a prescribed dose of 45Gy to 95％of PTV.Many kinds of parameters of these plans in each patient were compared: isodose distributions line、dose-volume histogram(DVH)、V95%、V110%、CI、HI、EI of target volume and the dose of related critical organs. Results: IMRT was superior to 3DCRT and 7F-RT in dose uniformity（p＜0.05）, there was no statistical difference between 3DCRT and 7FRT in CI（p>0.05）.IMRT had better dose conformity than 3DCRT and 7FRT（p＜0.05）, and 3DCRT was better than 7FRT in CI（p＜0.05）.IMRT showed better EI than 3DCRT and 7FRT（p＜0.05）,there was no statistical difference between 3DCRT and 7FRT in EI（p>0.05）.IMRT had advantage at sparing liver compared with 3DCRT and 7FRT（p＜0.05）,7FRT showed better D1/3 of liver than 3DCRT（p＜0.05）,but there was no statistical difference between 3DCRT and 7FRT in Dmean of liver（p>0.05）.IMRT expressed better Dmax of spinal cord than 3DCRT and 7F-RT（p＜0.05）, and 7FRT was better than IMRT in Dmax of spinal cord（p＜0.05）.But the dose received by the both kidneys were not significantly different. Conclusion: IMRT is superior to 3DCRT and 7FRT,and 3DCRT plans showed better CI and Dmax of spinal cord composed to 7FRT,and 7FRT was superior to 3DCRT in D1/3 of liver. IMRT for gastric cancer had physics advantage for clinical application.

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Dosimetric comparison between the prostate intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) plans using the planning target volume (PTV) dose–volume factor

Journal of Radiotherapy in Practice ◽

10.1017/s1460396916000194 ◽

2016 ◽

Vol 15 (3) ◽

pp. 263-268 ◽

Cited By ~ 6

Author(s):

James C. L. Chow ◽

Runqing Jiang ◽

Alexander Kiciak ◽

Daniel Markel

Keyword(s):

Planning Target Volume ◽

Volumetric Modulated Arc Therapy ◽

Intensity Modulated Radiotherapy ◽

Target Volume ◽

Conformity Index ◽

Volume Factor ◽

Dose Volume Histograms ◽

Intensity Modulated ◽

Dose Volume ◽

Arc Therapy

AbstractBackgroundWe demonstrated that our proposed planning target volume (PTV) dose–volume factor (PDVF) can be used to evaluate the PTV dose coverage between the intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) plans based on 90 prostate patients.PurposePDVF were determined from the prostate IMRT and VMAT plans to compare their variation of PTV dose coverage. Comparisons of the PDVF with other plan evaluation parameters such as D5%, D95%, D99%, Dmean, conformity index (CI), homogeneity index (HI), gradient index (GI) and prostate tumour control probability (TCP) were carried out.Methods and materialsProstate IMRT and VMAT plans using the 6 MV photon beams were created from 40 and 50 patients, respectively. Dosimetric indices (CI, HI and GI), dose–volume points (D5%, D95%, D99% and Dmean) and prostate TCP were calculated according to the PTV dose–volume histograms (DVHs) of the plans. All PTV DVH curves were fitted using the Gaussian error function (GEF) model. The PDVF were calculated based on the GEF parameters.ResultsFrom the PTV DVHs of the prostate IMRT and VMAT plans, the average D99% of the PTV for IMRT and VMAT were 74·1 and 74·5 Gy, respectively. The average prostate TCP were 0·956 and 0·958 for the IMRT and VMAT plans, respectively. The average PDVF of the IMRT and VMAT plans were 0·970 and 0·983, respectively. Although both the IMRT and VMAT plans showed very similar prostate TCP, the dosimetric and radiobiological results of the VMAT technique were slightly better than IMRT.ConclusionThe calculated PDVF for the prostate IMRT and VMAT plans agreed well with other dosimetric and radiobiological parameters in this study. PDVF was verified as an alternative of evaluation parameter in the quality assurance of prostate treatment planning.

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Impact of different treatment plans on EQD2 for intracavitary brachytherapy of cervical cancer

Journal of the Egyptian National Cancer Institute ◽

10.1186/s43046-021-00084-2 ◽

2021 ◽

Vol 33 (1) ◽

Author(s):

Osman Vefa Gul ◽

Gokcen Inan ◽

Hamit Basaran

Keyword(s):

Cervical Cancer ◽

Small Intestine ◽

Organs At Risk ◽

External Beam Radiotherapy ◽

High Dose Rate ◽

Intracavitary Brachytherapy ◽

High Dose ◽

Dose Volume Histograms ◽

Significant Difference ◽

Treatment Plans

Abstract Background Cancer is one of the leading causes of death worldwide. According to GLOBOCAN estimates, there were 341,831 deaths from cervical cancer in 185 countries in 2020. The aim of this study was to compare equieffective dose (EQD2) at 2 Gy per fraction by using dose volume histograms (DVHs) derived from external beam radiotherapy (EBRT) and high-dose rate brachytherapy (HDR-BRT) treatment plans used in cervical cancer radiotherapy. Methods Fifteen patients with stage IIB-IIIB cervical cancer were included in this retrospective study. Treatment with three-dimensional conformal radiotherapy (3D-CRT) or intensity-modulated radiotherapy (IMRT) was planned for all patients in 28 fractions, with a total of 50.4 Gy to be delivered to the whole pelvic region. After EBRT, manual optimization (MO) or inverse optimization (IO) HDR-BRT plans were created in 4 fractions with a total of 28 Gy. The plans obtained were grouped as IMRT + IO, IMRT + MO, 3DCRT + IO, and 3DCRT + MO by calculating EQD2s among these plans. D90, D95, and D98 values were compared in all plans for CTVHR total EQD2. In addition, EQD2 values for critical organs at risk (OARs) such as rectum, bladder, small intestine, and sigmoid were compared in all plans for volumes of 2 cm3, 1 cm3, and 0.1 cm3, respectively. Results There was no significant difference between the treatment groups in terms of CTVHR D90 and CTVIR D90 values; However, CTVHR D95 (p = 0.000) and CTVHR D98 (p = 0.000) values were found to be better in IMRT + IO technique. The IMRT + IO technique provided better protection for 2 cm3, 1 cm3, and 0.1 cm3 volumes of OARs compared to other techniques. Conclusions Considering all parameters such as CTVHR, CTVIR, rectum, bladder, small intestine, and sigmoid, combination of IMRT + IO treatment option was found to be significantly superior in total EQD2 calculations compared to other plans.

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Bony-based and prostate-based image guidance for lo-calized prostate cancer radiotherapy

Brazilian Journal of Radiation Sciences ◽

10.15392/bjrs.v8i1.1175 ◽

2020 ◽

Vol 8 (1) ◽

Author(s):

Saulo Santos Fortes ◽

Luiz Antonio Ribeiro Da Rosa

Keyword(s):

Prostate Cancer ◽

Normal Tissue ◽

Bone Structure ◽

Absorbed Dose ◽

Target Volume ◽

Image Guided Radiotherapy ◽

Beam Modulation ◽

Significant Difference ◽

Treatment Volume ◽

Treatment Plans

An important modality for the treatment of prostate cancer is teletherapy. The use of image-guided radiotherapy (IGRT) is a valuable tool in this treatment. This study retrospectively compared how repositioning the patient based on bone structure (B-ISO) and the prostate itself (P-ISO) affected the volumetric dose in the rectum, bladder, and clinical treatment volume (CTV). Additionally, the probability of normal tissue complication (NTCP) for the rectum was computed. We evaluated 155 cone-beam computed tomography (CBCT) from 8 patients. The treatment plans used beam modulation techniques. The planning target volume (PTV) margin adopted in both scenarios was 1 cm. The organs of interest were outlined over each CBCT and then treatment plans were applied so that the absorbed dose could be computed. NTCP values were calculated for the rectum. Analyzing dose-volume metrics published by the Quantitative Analysis of Normal Tissue Effects in the Clinic (QUANTEC), there was no significant difference between the two repositioning strategies for the rectum and bladder. There was a slight degradation in CTV coverage for the B-ISO strategy, but still with adequate coverage. Analysis of the uniform equivalent dose (EUD) and NTCP for the rectum showed little sensitivity to the strategy used. The present study showed that the use of CBCT in radiotherapy for prostate cancer treatment did not significantly improve volumetric doses for the rectum, bladder, and CTV, as well as NTCP for the rectum.

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Dosimetric evaluation of the heart and left anterior descending artery dose in radiotherapy for Japanese patients with breast cancer

Journal of Radiation Research ◽

10.1093/jrr/rrz087 ◽

2019 ◽

Vol 61 (1) ◽

pp. 134-139

Author(s):

Osamu Tanaka ◽

Kousei Ono ◽

Takuya Taniguchi ◽

Chiyoko Makita ◽

Masayuki Matsuo

Keyword(s):

Breast Cancer ◽

Volumetric Modulated Arc Therapy ◽

Intensity Modulated Radiotherapy ◽

Japanese Patients ◽

Target Volume ◽

The Other ◽

High Coverage ◽

Left Anterior Descending Artery ◽

Treatment Plans ◽

Field Static

Abstract Intensity-modulated radiotherapy (IMRT) has been used for breast cancer as well as in field-in-field techniques. Few dosimetric comparison studies have been conducted using IMRT and volumetric modulated arc therapy (VMAT) for Japanese patients. We aimed to study such patients. Thirty-two patients with left-sided breast cancer were enrolled. We conducted the following five treatment plans: two field-static IMRT (2F-S-IMRT), four field-static IMRT (4F-S-IMRT), 40° dual partial arc VMAT (40d-VMAT), 80° dual partial arc VMAT (80d-VMAT) and 210° partial VMAT (210p-VMAT). We evaluated the following: level of coverage of planning target volume (PTV) of 95% for irradiation at a dose of 50 Gy (D95) and the percentage of the heart and left anterior descending artery (LAD) volume that received 10 Gy or more (V10). As a result, the coverage of 40d-VMAT for the prescribed PTV dose of D95 was significantly lower than that of the other treatment plans (P < 0.05). Regarding heart V10 and LAD V10, 2F-S-IMRT, 40d-VMAT and 80d-VMAT showed significantly lower dose than the other treatment plans (P < 0.05). In conclusion, among the five plans, 2F-S-IMRT is recommended for Japanese patients because of high coverage of D95 of PTV, low V10 of the heart and LAD and the monitor unit value was the lowest.

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