Dosimetry for Organs at Risk With and Without Use of Perirectal Hydrogel Spacer in Prostate Cancer Patients Treated With SBRT

Background/ Aim. Transition from standard to highly conformal radiation therapy techniques, requires implementation of complex advanced dosimetry. The aim of the work was comparison of dosimetric parameters of 3DCRT and VMAT plan, as well as complications after treatment in relation to dosimetric parameters at gynecological cancer patients. Methods. Forty-nine gynecological cancer patients were included in the study. All patients were planned for 3D CRT, but due to unacceptable doses to organs at risk, treatment plans for IMRT or VMAT were generated for 21 patients. The patients were prescribed 50.4 Gy/28 fractions (4) and 45 Gy/25 fractions (45 patients). The coverage of PTV and doses to organs at risk were recorded. PTV margins were evaluated for both techniques according to the Van Herk formula. Results. ICRU 83 criteria were fulfilled in all 3DCRT /VMAT/IMRT plans providing optimal coverage of PTV. Doses to OARS: in average, the V45Gy in small bowel in IMRT/VMAT plans was four times smaller than the same of 3DCRT plans. The V45Gy of small bowels was in average 49.4cm3 in IMRT/VMAT plans, while in 3DCRT plans it was 211.6 cm3. In case of femoral head, significant reduction in V30Gy (10.8 % vs. 33.1%) and mean dose in case of IMRT/VMAT plans was recorded (30.4 Gy in 3DCRT vs 23.6 Gy). Rectum was planned with significantly lower dose in terms of V30Gy (79.5% vs 95.2%) in IMRT/VMAT plans. Bladder was better spared in VMAT plans in terms of V40Gy (51% vs. 91%), but maximum dose was higher in VMAT plans than in 3DCRT (50.1 Gy to 48.1 Gy in average). For all OARs there is statistically significant difference registered at p>0.05. Toxicities recorded in VMAT and 3DCRT patients include mainly radiation induced cystitis and enteritis. Patients treated with 3DCRT generally have longer recovery time. Homogeneity index was 0.11 for VMAT plans and 0.09 for 3DCRT plans. Conclusions. Analysis of dosimetric parameters revealed significant differences in normal tissue doses for same 3DCRT and VMAT patient, which confirmed necessity for implementation of advanced techniques for as many patients as possible.

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Identifying organs at risk for radiation-induced late dysphagia in head and neck cancer patients

Clinical and Translational Radiation Oncology ◽

10.1016/j.ctro.2019.08.005 ◽

2019 ◽

Vol 19 ◽

pp. 87-95

Author(s):

Johanna Hedström ◽

Lisa Tuomi ◽

Caterina Finizia ◽

Caroline Olsson

Keyword(s):

At Risk ◽

Head And Neck Cancer ◽

Head And Neck ◽

Cancer Patients ◽

Neck Cancer ◽

Organs At Risk ◽

Radiation Induced

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EP-1901 Identifying organs at risk for radiationinduced dysphagia in head and neck cancer patients

Radiotherapy and Oncology ◽

10.1016/s0167-8140(19)32321-7 ◽

2019 ◽

Vol 133 ◽

pp. S1033-S1034

Author(s):

J. Hedström ◽

L. Tuomi ◽

C. Finizia ◽

C. Olsson

Keyword(s):

At Risk ◽

Head And Neck Cancer ◽

Head And Neck ◽

Cancer Patients ◽

Neck Cancer ◽

Organs At Risk

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The Use of Ultrasound Imaging in the External Beam Radiotherapy Workflow of Prostate Cancer Patients

BioMed Research International ◽

10.1155/2018/7569590 ◽

2018 ◽

Vol 2018 ◽

pp. 1-16 ◽

Cited By ~ 11

Author(s):

Saskia M. Camps ◽

Davide Fontanarosa ◽

Peter H. N. de With ◽

Frank Verhaegen ◽

Ben G. L. Vanneste

Keyword(s):

Prostate Cancer ◽

Cancer Patients ◽

Ultrasound Imaging ◽

Organs At Risk ◽

External Beam Radiotherapy ◽

Treatment Options ◽

Current Status ◽

Tumor Control ◽

External Beam ◽

Image Guided Radiotherapy

External beam radiotherapy (EBRT) is one of the curative treatment options for prostate cancer patients. The aim of this treatment option is to irradiate tumor tissue, while sparing normal tissue as much as possible. Frequent imaging during the course of the treatment (image guided radiotherapy) allows for determination of the location and shape of the prostate (target) and of the organs at risk. This information is used to increase accuracy in radiation dose delivery resulting in better tumor control and lower toxicity. Ultrasound imaging is harmless for the patient, it is cost-effective, and it allows for real-time volumetric organ tracking. For these reasons, it is an ideal technique for image guidance during EBRT workflows. Review papers have been published in which the use of ultrasound imaging in EBRT workflows for different cancer sites (prostate, breast, etc.) was extensively covered. This new review paper aims at providing the readers with an update on the current status for prostate cancer ultrasound guided EBRT treatments.

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Evaluation of Deep Learning-Based Auto-Segmentation of Target Volume and Organs-at-Risk in Breast Cancer Patients

International Journal of Radiation Oncology*Biology*Physics ◽

10.1016/j.ijrobp.2020.07.235 ◽

2020 ◽

Vol 108 (3) ◽

pp. e779

Author(s):

S.Y. Chung ◽

J.S. Chang ◽

Y. Chang ◽

B.S. Choi ◽

J. Chun ◽

...

Keyword(s):

Breast Cancer ◽

At Risk ◽

Deep Learning ◽

Cancer Patients ◽

Organs At Risk ◽

Target Volume ◽

Breast Cancer Patients

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Trade-off between the conflicting planning goals in correlation with patient’s anatomical parameters for intensity-modulated radiotherapy of prostate cancer patients

Journal of Radiotherapy in Practice ◽

10.1017/s1460396919000025 ◽

2019 ◽

Vol 18 (03) ◽

pp. 232-238 ◽

Cited By ~ 2

Author(s):

Amin Banaei ◽

Bijan Hashemi ◽

Mohsen Bakhshandeh ◽

Bahram Mofid

Keyword(s):

Prostate Cancer ◽

Cancer Patients ◽

Organs At Risk ◽

Intensity Modulated Radiotherapy ◽

Normal Tissue Complication Probability ◽

Target Dose ◽

Trade Off ◽

Intensity Modulated ◽

Dose Constraints ◽

Anatomical Parameters

AbstractAimTo quantify the relationship between the planning target volume (PTV) dose homogeneity and organs at risk (OARs) sparing in correlation with anatomical parameters in prostate intensity-modulated radiotherapy (IMRT).Materials and methodsNine IMRT plans with various target dose constraints’ priorities were created for 15 prostate cancer patients. Selected PTV and OARs parameters were calculated for the patients. A trade-off was assessed between homogeneity index (HI) and OAR sparing. Several anatomical parameters were evaluated to investigate their effects on the OAR sparing and HI.ResultsInverse exponential relationships were found between the OAR sparing and HI (average R 2 of 0·983 and 0·994 for bladder and rectum, respectively). Decreasing the priority led to more OARs sparing (normal tissue complication probability reduction: 97·6 and 74·5%; mean dose reduction: 16·3 and 11·3% for bladder and rectum, respectively) and worsening of the HI (0·095–0·322) but with no significant effect on tumour control probability. Furthermore, OARs volumes, distances between OARs and PTV and their joint volumes had stronger correlations with OARs’ mean doses.ConclusionEnforcement of target dose constraints was more effective on the improvement of HIs for the patients with initial high HI values at low dose constraints’ priorities. Reducing the priority had more effects on the OARs sparing compared to HI, especially for the patients with high OAR doses in high priority plans. This can be attributed to smaller distances or greater joint volumes between the OARs and PTV.

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