Skin dose measurement and estimating the dosimetric effect of applicator misplacement in gynecological brachytherapy: A patient and phantom study

2021 ◽  
pp. 1-13
Author(s):  
Mehrsa Majdaeen ◽  
Masoumeh Dorri—Giv ◽  
Shaghayegh Olfat ◽  
Gholamreza Ataei ◽  
Razzagh Abedi-Firouzjah ◽  
...  
Keyword(s):  
Dose Calculation ◽  
Planning System ◽  
Treatment Planning System ◽  
Future Research ◽  
Skin Dose ◽  
Surface Dose ◽  
Dose Measurement ◽  
Left And Right ◽  
The Mean ◽  
Skin Doses

OBJECTIVES: To evaluate skin dose differences between TPS (treatment planning system) calculations and TLD (thermo-luminescent dosimeters) measurements along with the dosimetric effect of applicator misplacement for patients diagnosed with gynecological (GYN) cancers undergoing brachytherapy. METHODS: The skin doses were measured using TLDs attached in different locations on patients’ skin in pelvic regions (anterior, left, and right) for 20 patients, as well as on a phantom. In addition, the applicator surface dose was calculated with TLDs attached to the applicator. The measured doses were compared with TPS calculations to find TPS accuracy. For the phantom, different applicator shifts were applied to find the effect of applicator misplacement on the surface dose. RESULTS: The mean absolute dose differences between the TPS and TLDs results for anterior, left, and right points were 3.14±1.03, 6.25±1.88, and 6.20±1.97 %, respectively. The mean difference on the applicator surface was obtained 1.92±0.46 %. Applicator misplacements of 0.5, 2, and 4 cm (average of three locations) resulted in 9, 36, and 61%, dose errors respectively. CONCLUSIONS: The surface/skin differences between the calculations and measurements are higher in the left and right regions, which relate to the higher uncertainty of TPS dose calculation in these regions. Furthermore, applicator misplacements can result in high skin dose variations, therefore it can be an appropriate quality assurance method for future research.

Skin dose assessment with treatment planning system (TPS) and skin reaction evaluation of early breast cancer patients treated via an intraoperative radiation therapy (IORT) device

2018 ◽  
Vol 17 (4) ◽  
pp. 417-421
Author(s):  
Omid Baziar ◽  
Hamid Gholamhosseinian ◽  
Mohammad Naser Forghani
Keyword(s):  
Breast Cancer ◽  
Cancer Patients ◽  
Planning System ◽  
Treatment Planning System ◽  
Intraoperative Radiation Therapy ◽  
Skin Dose ◽  
Breast Cancer Patients ◽  
Skin Reactions ◽  
Intraoperative Radiation ◽  
Skin Doses

AbstractPurposeTo assess skin dose and incidence of skin reactions in early breast cancer patients treated via Intrabeam™ intraoperative radiation therapy (IORT) device.Materials and methodsIn total, 250 breast cancer patients treated with a single fraction of 20 Gy using 50 kV photon were recruited. The applicator to skin distance (ASD) was measured before the initiation of the radiation and the skin dose in each patient was accordingly calculated based on the treatment planning system (TPS).ResultsThe average skin doses calculated were equal to 7·91, 5·83, 3·96 and 2·14 Gy for 6–10, 10–15, 15–20 and 20–30 mm ASD values, respectively. It is noticeable that the skin doses could be lower than the TPS measurements up to 45%, mostly due to lack of backscatter radiation in breast tissue compared with the full scatter condition in the Zeiss water phantom. Finally, only three patients showed low-grade skin reactions 1 week after IORT. A review of the related literature also revealed the incidence of lower skin complications among patients treated via Intrabeam™ compared with MammoSite™ machine.ConclusionsThe Intrabeam™ TPS did not seem to be very reliable for accurate skin dosimetry. However, breast cancer treatment using Intrabeam™ could result in fewer incidences of skin reactions than MammoSite™ machine.

Evaluation of thermoplastic Klarity mask use during intensity-modulated radiation therapy for head and neck carcinoma

2018 ◽  
Vol 17 (2) ◽  
pp. 171-178 ◽  
Author(s):  
Khaldoon Radaideh
Keyword(s):  
Radiation Therapy ◽  
Head And Neck ◽  
Intensity Modulated Radiation Therapy ◽  
Planning System ◽  
Skin Dose ◽  
Surface Dose ◽  
Thermoluminescent Dosimeters ◽  
Intensity Modulated ◽  
Skin Doses ◽  
Dose Measurements

AbstractAimTo evaluate the Klarity® Mask with respect to skin doses and toxicity secondary to head and neck cancer radiation treatment.Materials and methodsThis prospective study included five nasopharyngeal cancer patients who underwent intensity-modulated radiation therapy and monitored for skin toxicity. An anatomical Perspex head and neck phantom was designed and used. All patients’ treatment plans were separately transferred to the phantom. Dosimetric measurements were performed using chip-shaped thermoluminescent dosimeters (LiF:Mg,Ti TLDs) which were distributed at certain target points on the phantom. Phantom was irradiated twicely with and without a Klarity® Mask. Three fractions for each patient plan were obtained and compared with treatment planning system (TPS) doses as guided by computed tomography.ResultsThe Klarity mask used for patient immobilisation increased the surface dose by 10·83% more than that without the mask. The average variations between skin dose measurements with and without the Klarity mask for all patients’ plans ranged from 10·26 to 11·83%. TPS overestimated the surface dose by 19·13% when compared with thermoluminescent dosimeters that measured the direct skin dose.ConclusionsKlarity immobilisation mask increases skin doses, as a consequence, surface dose measurements should be monitored and must be taken into account.

scholarly journals Comparison of Different Algorithms in the Radiotherapy Plans of Breast Cancer

2018 ◽  
Vol 22 ◽  
pp. 01048 ◽  
Author(s):  
Yonca Yahşi Çelen ◽  
Atilla Evcin
Keyword(s):  
Breast Cancer ◽  
Dose Calculation ◽  
Planning System ◽  
Treatment Planning System ◽  
Average Dose ◽  
Mean Values ◽  
Portal Dosimetry ◽  
Calculation Algorithms ◽  
Dose Calculation Algorithms ◽  
The Mean

It is aimed to evaluate portal dosimetry results of planned breast cancer patients with intensity-modulated radiotherapy (YART) of Anisotropic Analytical Algorithm (AAA) and Pencil Beam Convolution (PBC) dose calculation algorithms. The plans of 10 treated patients will receive 6 MV photon energy and a total of 25 fractions of 50 Gray dose using the inverse YART technique, which is reverse planned in the Eclipse (ver.13.6) treatment planning system with Varian Trilogy Linear Accelerator prescribing. For each plan, dose was calculated after optimization using PBC and then AAA algorithms. The quality controls of the plans were made using the Electronic Portal Imaging Device (EPID) by creating individual verification plans for each algorithm. In addition, the maximum and average dose values in the target volume were compared in inverse YART plans calculated using PBC and AAA. When treatment plans generated by AAA and PBC dose calculation algorithms are analyzed using EPID, for the PBC algorithm, the mean values of VArea and VAvg are 98.15 ± 1.07, 0.40 ± 0.048 and 98.72 ± 1.13, 0.37 ± 0.051, respectively, for the AAA algorithm. The PTV Dmax value for the PBC algorithm is 109.3 ± 1.09 and the DAvg value is 101.7 ± 0.51. For the AAA algorithm, the PTV Dmax value is 110.6 ± 1.12 and the DAvg value is 102.9 ± 0.62. When the mean values of portal dosimetry VArea and VAvg evaluated using PBC and AAA algorithms were compared, the differences between the algorithms were not statistically significant (p> 0.05). Differences between the algorithms for PTV Dmax and DAvg values are not statistically significant (p> 0.05).

scholarly journals Experimental evaluation of the accuracy of skin dose calculation for a commercial treatment planning system

2008 ◽  
Vol 9 (1) ◽  
pp. 29-35 ◽  
Author(s):  
Laurence E. Court ◽  
Roy B. Tishler ◽  
Aaron M. Allen ◽  
Hong Xiang ◽  
Mike Makrigiorgos ◽  
...  
Keyword(s):  
Treatment Planning ◽  
Experimental Evaluation ◽  
Dose Calculation ◽  
Planning System ◽  
Treatment Planning System ◽  
Skin Dose

The effect of carbon fibre treatment couch with and without immobilisation devices on radiotherapy dose calculation using three different planning algorithms and photon beam energies

2021 ◽  
pp. 1-5
Author(s):  
Y. Oulhouq ◽  
A. Rrhioua ◽  
D. Bakari ◽  
M. Zerfaoui ◽  
D. Krim
Keyword(s):  
Carbon Fibre ◽  
Three Dimensional ◽  
Treatment Protocol ◽  
Dose Calculation ◽  
Patient Positioning ◽  
Planning System ◽  
Treatment Planning System ◽  
Skin Dose ◽  
Body Contour ◽  
Calculation Algorithms

Abstract Introduction: The objective of radiotherapy immobilisation devices is to improve the reproducibility of patient positioning during treatment sessions. The inclusion of these devices in the treatment protocol may increase the skin dose. In practice, these devices are not systematically taken into account in the dose calculation. Material and methods: In this study, the dosimetric effects of the carbon fibre couch iBEAM Evo Extension 415, with and without three different immobilisation devices (a Klarity Breastboard R610-2ECF, a Bionix Butterfly Board and CIVCO Vac-Lok vacuum bag), were calculated and evaluated on the dose calculation for conformal three-dimensional radiation therapy. The measurements were carried out by comparing the measured dose with the one calculated for three different algorithms, FFT convolution, fast superposition and superposition algorithms, which are implemented in Xio treatment planning system (TPS). Results: Dosimetric tolerance levels have been respected for specific dose calculations, which do not include the fibre couch with or without immobilisation devices. Errors of up to 8% in the dose calculation were obtained for the beams passing through the fibre couch and the breast board base support region. Conclusion: According to the significant attenuation differences of the beam by the fibre couch and immobilisation devices, it was concluded that ignoring the device in the dose calculation can change patient’s skin and target doses. The fibre couch and immobilisation device should be included within external body contour to account for the TPS calculation algorithms dose attenuation.

scholarly journals Evaluation of clinical implications in the use of dose to water versus dose to medium by using NTCP and TCP models for urinary bladder tumours

2021 ◽  
Vol 27 (1) ◽  
pp. 19-24
Author(s):  
Avinav Bharati ◽  
Susama R Mandal ◽  
Anoop K Srivastava ◽  
Madhup Rastogi ◽  
Rohini Khurana ◽  
...  
Keyword(s):  
Urinary Bladder ◽  
Planning System ◽  
Treatment Planning System ◽  
Clinical Implications ◽  
Dose Distributions ◽  
Patients With Cancer ◽  
System A ◽  
Left And Right ◽  
The Mean ◽  
Bladder Tumours

Abstract Purpose: To analyze the dosimetric and radiobiological differences between dose to water versus dose to medium for patients with carcinoma of the urinary bladder. Materials and Methods: 15 patients with cancer of urinary bladder were selected for the study. VMAT plans were generated for each patient. The dose distributions were calculated in the modes dose to water and to medium with the Monaco treatment planning system. A dosimetric comparative analysis has been made between the two modes of planning in this study. Subsequently, NTCP and TCP were determined for OARs and targets respectively. Results: The mean dose to 2 cc of the rectum, small bowel, left and right femoral heads respectively was higher by 0.8, 1.2, 2.7, and 2.2% for the dose to water calculation. Similarly, the mean dose to D2, D50, and D98 for PTV was higher by 0.4, 0.3, and 0.3% for dose to water calculation. Such small dose differences had little effect on the values of TCP and NTCP. Conclusion: For patients with the urinary bladder there were very small differences between results between calculations carried out in dose to medium and dose to water modes.

scholarly journals Dosimetric effects of supine immobilization devices on the skin in intensity-modulated radiation therapy for breast cancer: a retrospective study

BMC Cancer ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ran Lv ◽  
Guangyi Yang ◽  
Yongzhi Huang ◽  
Yanhong Wang
Keyword(s):  
Breast Cancer ◽  
Radiation Therapy ◽  
Retrospective Study ◽  
Intensity Modulated Radiation Therapy ◽  
Radical Mastectomy ◽  
Planning System ◽  
Treatment Planning System ◽  
Skin Dose ◽  
Intensity Modulated ◽  
Left And Right

Abstract Background The dose perturbation effect of immobilization devices is often overlooked in intensity-modulated radiation therapy (IMRT) for breast cancer (BC). This retrospective study assessed the dosimetric effects of supine immobilization devices on the skin using a commercial treatment planning system. Methods Forty women with BC were divided into four groups according to the type of primary surgery: groups A and B included patients with left and right BC, respectively, who received 50 Gy radiotherapy in 25 fractions after radical mastectomy, while groups C and D included patients with left and right BC, respectively, who received breast-conservation surgery (BCS) and 40.05 Gy in 15 fractions as well as a tumor bed simultaneous integrated boost to 45 Gy. A 0.2-cm thick skin contour and two sets of body contours were outlined for each patient. Dose calculations were conducted for the two sets of contours using the same plan. The dose differences were assessed by comparing the dose-volume histogram parameter results and by plan subtraction. Results The supine immobilization devices for BC resulted in significantly increased skin doses, which may ultimately lead to skin toxicity. The mean dose increased by approximately 0.5 and 0.45 Gy in groups A and B after radical mastectomy and by 2.7 and 3.25 Gy in groups C and D after BCS; in groups A–D, the percentages of total normal skin volume receiving equal to or greater than 5 Gy (V5) increased by 0.54, 1.15, 2.67, and 1.94%, respectively, while the V10 increased by 1.27, 1.83, 1.36, and 2.88%; the V20 by 0.85, 1.87, 2.76, and 4.86%; the V30 by 1.3, 1.24, 10.58, and 11.91%; and the V40 by 1.29, 0.65, 10, and 10.51%. The dose encompassing the planning target volume and other organs at risk, showed little distinction between IMRT plans without and with consideration of immobilization devices. Conclusions The supine immobilization devices significantly increased the dose to the skin, especially for patients with BCS. Thus, immobilization devices should be included in the external contour to account for dose attenuation and skin dose increment. Trial registration This study does not report on interventions in human health care.

Dosimetric comparison of fractionated radiosurgery plans using frameless Gamma Knife ICON and CyberKnife systems with linear accelerator–based radiosurgery plans for multiple large brain metastases

2020 ◽  
Vol 132 (5) ◽  
pp. 1473-1479 ◽  
Author(s):  
Eun Young Han ◽  
He Wang ◽  
Dershan Luo ◽  
Jing Li ◽  
Xin Wang
Keyword(s):  
Brain Metastases ◽  
Gamma Knife ◽  
Linear Accelerator ◽  
Treatment Time ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Normal Brain ◽  
Large Brain ◽  
The Mean

OBJECTIVEFor patients with multiple large brain metastases with at least 1 target volume larger than 10 cm3, multifractionated stereotactic radiosurgery (MF-SRS) has commonly been delivered with a linear accelerator (LINAC). Recent advances of Gamma Knife (GK) units with kilovolt cone-beam CT and CyberKnife (CK) units with multileaf collimators also make them attractive choices. The purpose of this study was to compare the dosimetry of MF-SRS plans deliverable on GK, CK, and LINAC and to discuss related clinical issues.METHODSTen patients with 2 or more large brain metastases who had been treated with MF-SRS on LINAC were identified. The median planning target volume was 18.31 cm3 (mean 21.31 cm3, range 3.42–49.97 cm3), and the median prescribed dose was 27.0 Gy (mean 26.7 Gy, range 21–30 Gy), administered in 3 to 5 fractions. Clinical LINAC treatment plans were generated using inverse planning with intensity modulation on a Pinnacle treatment planning system (version 9.10) for the Varian TrueBeam STx system. GK and CK planning were retrospectively performed using Leksell GammaPlan version 10.1 and Accuray Precision version 1.1.0.0 for the CK M6 system. Tumor coverage, Paddick conformity index (CI), gradient index (GI), and normal brain tissue receiving 4, 12, and 20 Gy were used to compare plan quality. Net beam-on time and approximate planning time were also collected for all cases.RESULTSPlans from all 3 modalities satisfied clinical requirements in target coverage and normal tissue sparing. The mean CI was comparable (0.79, 0.78, and 0.76) for the GK, CK, and LINAC plans. The mean GI was 3.1 for both the GK and the CK plans, whereas the mean GI of the LINAC plans was 4.1. The lower GI of the GK and CK plans would have resulted in significantly lower normal brain volumes receiving a medium or high dose. On average, GK and CK plans spared the normal brain volume receiving at least 12 Gy and 20 Gy by approximately 20% in comparison with the LINAC plans. However, the mean beam-on time of GK (∼ 64 minutes assuming a dose rate of 2.5 Gy/minute) plans was significantly longer than that of CK (∼ 31 minutes) or LINAC (∼ 4 minutes) plans.CONCLUSIONSAll 3 modalities are capable of treating multiple large brain lesions with MF-SRS. GK has the most flexible workflow and excellent dosimetry, but could be limited by the treatment time. CK has dosimetry comparable to that of GK with a consistent treatment time of approximately 30 minutes. LINAC has a much shorter treatment time, but residual rotational error could be a concern.

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