Transrectal ultrasound for intraoperative interstitial needle guidance in cervical cancer brachytherapy.

OBJECTIVE: This study aimed to prospectively assess the visibility of interstitial needles on transrectal ultrasound (TRUS) in cervical cancer brachytherapy patients and evaluate its impact on implant and treatment plan quality. MATERIAL AND METHODS: TRUS was utilized during and after applicator insertion, with each needle's visibility documented through axial images at the high-risk clinical target volume's largest diameter. Needle visibility on TRUS was scored from 0 (no visibility) to 3 (excellent discrimination, margins distinct). Quantitative assessment involved measuring the distance between tandem and each needle on TRUS and comparing it to respective magnetic resonance imaging (MRI) measurements. Expected treatment plan quality based on TRUS images was rated from 1 (meeting all planning objectives) to 4 (violation of High-risk clinical target volume (CTVHR) and/or organ at risk (OAR) hard constraints) and compared to the final MRI-based plan. RESULTS: Analysis included 23 patients with local FIGO stage IB2-IVA, comprising 41 applications with a total of 230 needles. A high visibility rate of 99.1% (228/230 needles) was observed, with a mean visibility score of 2.5 ±â€¯0.7 for visible needles. The maximum and mean difference between MRI and TRUS measurements were 8 mm and -0.1 ±â€¯1.6 mm, respectively, with > 3 mm discrepancies in 3.5% of needles. Expected treatment plan quality after TRUS assessment exactly aligned with the final MRI plan in 28 out of 41 applications with only minor deviations in all other cases. CONCLUSION: Real-time TRUS-guided interstitial needle placement yielded high-quality implants, thanks to excellent needle visibility during insertion. This supports the potential of TRUS-guided brachytherapy as a promising modality for gynecological indications.

Impact of transitioning to an online course - A report from the ESTRO gyn teaching course.

INTRODUCTION: In 2020, the ESTRO course on image-guided radiotherapy and chemotherapy in gynaecological cancer was converted into an online version due to the COVID-19 pandemic. This paper describes the change process and evaluates the impact on participants compared with previous live courses. METHODS AND MATERIALS: The 2019 live course contained 41 h of educational content, comprising 33 h of synchronous activities (lectures, interactive activities, videos) and 8 h of homework (contouring, dose planning). For the online course, the lectures were provided as pre-course material (11 mandatory, 22 optional). Contouring/dose planning homework was unchanged. The synchronous sessions were reconfigured as six 2-hour webinars (total educational content ~38 h).Participant numbers/characteristics, engagement and satisfaction for six live courses and the online course were compared. RESULTS: Participant numbers for the online and live courses were similar (90 vs. mean 96). There were more participants from outside Europe (28% vs. mean 18%) and more non-doctors (47% vs. mean 33%). Proportion of participants responding to the pre-course questionnaire was similar (77% vs. mean 78%) but post-course questionnaire response was lower (62% vs. mean 92%).43% participants viewed ≥75% of mandatory lectures before the webinars. 86% viewed the optional lectures. Submissions of contouring and dose planning homework was higher (contouring 77%-90% vs. 56%-69%, dose planning 74%-89% vs. 29%-57%).96% (47/49) participants rated the online course as Excellent (43%) or Good (53%). Overall satisfaction was similar (4.4 vs. mean 4.6). CONCLUSION: Participant satisfaction and engagement with the online course remained high despite less contact time with faculty.

Clinical and imaging findings in cervical cancer and their impact on FIGO and TNM staging - An analysis from the EMBRACE study.

OBJECTIVE: To investigate differences in local tumour staging between clinical examination and MRI and differences between FIGO 2009, FIGO 2018 and TNM in patients with primary cervical cancer undergoing definitive radio-chemotherapy. METHODS: Patients from the prospective observational multi-centre study "EMBRACE" were considered for analysis. All patients had gynaecological examination and pelvic MRI before treatment. Nodal status was assessed by MRI, CT, PET-CT or lymphadenectomy. For this analysis, patients were restaged according to the FIGO 2009, FIGO 2018 and TNM staging system. The local tumour stage was evaluated for MRI and clinical examination separately. Descriptive statistics were used to compare local tumour stages and different staging systems. RESULTS: Data was available from 1338 patients. For local tumour staging, differences between MRI and clinical examination were found in 364 patients (27.2%). Affected lymph nodes were detected in 52%. The two most frequent stages with FIGO 2009 are IIB (54%) and IIIB (16%), with FIGO 2018 IIIC1 (43%) and IIB (27%) and with TNM T2b N0 M0 (27%) and T2b N1 M0 (23%) in this cohort. CONCLUSIONS: MRI and clinical examination resulted in a different local tumour staging in approximately one quarter of patients. Comprehensive knowledge of the differential value of clinical examination and MRI is necessary to define one final local stage, especially when a decision about treatment options is to be taken. The use of FIGO 2009, FIGO 2018 and TNM staging system leads to differences in stage distributions complicating comparability of treatment results. TNM provides the most differentiated stage allocation.

Multidimensional dosimetry of ¹°6Ru eye plaques using EBT3 films and its impact on treatment planning.

PURPOSE: The purpose of this study was to establish a method to perform multidimensional radiochromic film measurements of (106)Ru plaques and to benchmark the resulting dose distributions against Monte Carlo simulations (MC), microdiamond, and diode measurements. METHODS: Absolute dose rates and relative dose distributions in multiple planes were determined for three different plaque models (CCB, CCA, and COB), and three different plaques per model, using EBT3 films in an in-house developed polystyrene phantom and the mcnp6 MC code. Dose difference maps were generated to analyze interplaque variations for a specific type, and for comparing measurements against MC simulations. Furthermore, dose distributions were validated against values specified by the manufacturer (BEBIG) and microdiamond and diode measurements in a water scanning phantom. Radial profiles were assessed and used to estimate dosimetric margins for a given combination of representative tumor geometry and plaque size. RESULTS: Absolute dose rates at a reference depth of 2 mm on the central axis of the plaque show an agreement better than 5% (10%) when comparing film measurements (mcnp6) to the manufacturer's data. The reproducibility of depth-dose profile measurements was <7% (2 SD) for all investigated detectors and plaque types. Dose difference maps revealed minor interplaque deviations for a specific plaque type due to inhomogeneities of the active layer. The evaluation of dosimetric margins showed that for a majority of the investigated cases, the tumor was not completely covered by the 100% isodose prescribed to the tumor apex if the difference between geometrical plaque size and tumor base ≤4 mm. CONCLUSIONS: EBT3 film dosimetry in an in-house developed phantom was successfully used to characterize the dosimetric properties of different (106)Ru plaque models. The film measurements were validated against MC calculations and other experimental methods and showed a good agreement with data from BEBIG well within published tolerances. The dosimetric information as well as interplaque comparison can be used for comprehensive quality assurance and for considerations in the treatment planning of ophthalmic brachytherapy.