PurposeSkin cancers are the most common human malignancy with increasing incidence. Currently, surgery is standard of care treatment for non-melanoma skin cancers. However, brachytherapy is a growing modality in the management of skin cancers. Therefore, we aimed to assess the outcome of patients with non-melanoma skin cancers treated by high-dose-rate (HDR) brachytherapy with surface mold technique.Material and methodsIn this prospective study, we recruited patients with basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) of the skin who were candidates for definitive or adjuvant brachytherapy during 2013-2014. Alginate was used for making the individualized surface molds for each patient. Patients were treated with afterloading radionuclide HDR brachytherapy machine, with a total dose of 30-52 Gy in 10-13 fractions. Participants were followed for 2 years for radiation toxicity, cosmetic results, and local failures.ResultsA total of 60 patients (66.7% male; median age, 71 years) were included, of which 42 (70.0%) underwent definitive radiotherapy. Seventy-five percent of lesions were BCC. The mean total dose was 39.6 ± 5.4 Gy. Of patients in definitive group, 40/42 (95.2%) experienced complete clinical response after 3 months. The recurrence rate was 2/18 (11.11%) and 1/42 (2.38%) in adjuvant and definitive groups, respectively. The percentage of grade 3-4 acute (3-month post-treatment) and late toxicities (2 years post-treatment) was 6.7% and 0%, respectively. The cosmetic results were good/excellent in 96.2% of patients after 2 years of follow-up.ConclusionsWith appropriate patient selection and choosing as lowest dose per fraction as possible, HDR brachytherapy with customized surface molds yields good oncological and cosmetic results for the treatment of localized skin BCC and SCC.

Purpose: To evaluate the outcomes of ruthenium-106 ( 106 Ru) brachytherapy in terms of radiation parameters in patients with thick uveal melanomas.Material and methods: Medical records of 51 patients with thick (thickness ≥ 7 mm and < 11 mm) uveal melanoma treated with 106 Ru brachytherapy during a ten-year period were reviewed. Radiation parameters, tumor regression, best corrected visual acuity (BCVA), and treatment-related complications were assessed.Results: Fifty one eyes of 51 consecutive patients including 25 men and 26 women with a mean age of 50.5 ± 15.2 years were enrolled. Patients were followed for 36.1 ± 26.5 months (mean ± SD). Mean radiation dose to tumor apex and to sclera were 71 (± 19.2) Gy and 1269 (± 168.2) Gy. Radiation dose rates to tumor apex and to sclera were 0.37 (± 0.14) Gy/h and 6.44 (± 1.50) Gy/h. Globe preservation was achieved in 82.4%. Preoperative mean tumor thickness of 8.1 (± 0.9) mm decreased to 4.5 (± 1.6) mm, 3.4 (± 1.4) mm, and 3.0 (± 1.46) mm at 12, 24, and 48 months after brachytherapy (p = 0.03). Four eyes that did not show regression after 6 months of brachytherapy were enucleated. Secondary enucleation was performed in 5 eyes because of tumor recurrence or neovascular glaucoma. Tumor recurrence was evident in 6 (11.8%) patients. Mean Log MAR (magnification requirement) visual acuity declined from 0.75 (± 0.63) to 0.94 (± 0.5) (p = 0.04). Best corrected visual acuity of 20/200 or worse was recorded in 37% of the patients at the time of diagnosis and 61.7% of the patients at last exam (p = 0.04). Non-proliferative and proliferative radiation-induced retinopathy was observed in 20 and 7 eyes.Conclusions: Thick uveal melanomas are amenable to 106 Ru brachytherapy with less than recommended apex radiation dose and dose rates.

PurposeTo analyze the optimum organ filling point for organs at risk (OARs) dose in cervical cancer high-dose-rate (HDR) brachytherapy.Material and methodsIn a retrospective study, 32 locally advanced cervical cancer patients (97 insertions) who were treated with 3D conformal external beam radiation therapy (EBRT) and concurrent chemotherapy during 2010-2013 were included. Rotterdam HDR tandem-ovoid applicators were used and computed tomography (CT) scanning was performed after each insertion. The OARs delineation and GEC-ESTRO-based clinical target volumes (CTVs) contouring was followed by 3D forward planning. Then, dose volume histogram (DVH) parameters of organs were recorded and patients were classified based on their OARs volumes, as well as their inserted tandem length.ResultsThe absorbed dose to point A ranged between 6.5-7.5 Gy. D0.1cm3 and D2cm3 of the bladder significantly increased with the bladder volume enlargement (p value < 0.05). By increasing the bladder volume up to about 140 cm3, the rectum dose was also increased. For the cases with bladder volumes higher than 140 cm3, the rectum dose decreased. For bladder volumes lower than 75 cm3, the sigmoid dose decreased; however, for bladder volumes higher than 75 cm3, the sigmoid dose increased. The D2cm3 of the bladder and rectum were higher for longer tandems than for shorter ones, respectively. The divergence of the obtained results for different tandem lengths became wider by the extension of the bladder volume. The rectum and sigmoid volume had a direct impact on increasing their D0.1cm3 and D2cm3, as well as decreasing their D10, D30, and D50.ConclusionsThere is a relationship between the volumes of OARs and their received doses. Selecting a bladder with a volume of about 70 cm3 or less proved to be better with regards to the dose to the bladder, rectum, and sigmoid.

The aim of this study was to assess the actual dose delivered to the rectum and compare it with the treatment planning system (TPS) reports. In this study, the dose delivered to the rectum was measured by semiconductor diode detectors (PTW, Germany). The factors that influence diode response were investigated as well. Calibration factors of diodes were measured weekly to investigate the effect of time interval on the accuracy of calibration. Then 40 applications of patients with cervix carcinoma were evaluated. Rectum dose was measured by means of rectal dosemeter and compared with the TPS-calculated dose. In this research, the differences between the measured and the calculated dose were investigated. The mean difference between the TPS-calculated dose and the measured dose was 6.5% (range: -22 to +39) for rectum. The TPS-calculated maximum dose was typically higher than the measured maximum dose. The study showed that the main reason for the difference was due to the movements of the patient and applicator shift in the elapsed time between the imaging and treatment stage. It is recommended that in vivo dosimetry should be performed in addition to treatment planning computation. In vivo dosimetry is a reliable solution to compare the planned and actual dose delivered to organs at risk.

PurposeThis study was designed to assess the dose accumulation (DA) of bladder and rectum between brachytherapy fractions using hybrid-based deformable image registration (DIR) and compare it with the simple summation (SS) approach of GEC-ESTRO in cervical cancer patients.Material and methodsPatients (n = 137) with cervical cancer treated with 3D conformal radiotherapy and three fractions of high-dose-rate brachytherapy were selected. CT images were acquired to delineate organs at risk and targets according to GEC-ESTRO recommendations. In order to determine the DA for the bladder and rectum, hybrid-based DIR was done for three different fractions of brachytherapy and the results were compared with the standard GEC-ESTRO method. Also, we performed a phantom study to calculate the uncertainty of the hybrid-based DIR algorithm for contour matching and dose mapping.ResultsThe mean ± standard deviation (SD) of the Dice similarity coefficient (DICE), Jaccard, Hausdorff distance (HD) and mean distance to agreement (MDA) in the DIR process were 0.94 ±0.02, 0.89 ±0.03, 8.44 ±3.56 and 0.72 ±0.22 for bladder and 0.89 ±0.05, 0.80 ±0.07, 15.46 ±10.14 and 1.19 ±0.59 for rectum, respectively. The median (Q1, Q3; maximum) GyEQD2 differences of total D2cc between DIR-based and SS methods for the bladder and rectum were reduced by –1.53 (–0.86, –2.98; –9.17) and –1.38 (–0.80, –2.14; –7.11), respectively. The mean ± SD of DICE, Jaccard, HD, and MDA for contour matching were 0.98 ±0.008, 0.97 ±0.01, 2.00 ±0.70 and 0.20 ±0.04, respectively for large deformation. Maximum uncertainty of dose mapping was about 3.58%.ConclusionsThe hybrid-based DIR algorithm demonstrated low registration uncertainty for both contour matching and dose mapping. The DA difference between DIR-based and SS approaches was statistically significant for both bladder and rectum and hybrid-based DIR showed potential to assess DA between brachytherapy fractions.

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