RENEB Inter-Laboratory Comparison 2021: The Dicentric Chromosome Assay.

After large-scale radiation accidents where many individuals are suspected to be exposed to ionizing radiation, biological and physical retrospective dosimetry assays are important tools to aid clinical decision making by categorizing individuals into unexposed/minimally, moderately or highly exposed groups. Quality-controlled inter-laboratory comparisons of simulated accident scenarios are regularly performed in the frame of the European legal association RENEB (Running the European Network of Biological and Physical retrospective Dosimetry) to optimize international networking and emergency readiness in case of large-scale radiation events. In total 33 laboratories from 22 countries around the world participated in the current RENEB inter-laboratory comparison 2021 for the dicentric chromosome assay. Blood was irradiated in vitro with X rays (240 kVp, 13 mA, ∼75 keV, 1 Gy/min) to simulate an acute, homogeneous whole-body exposure. Three blood samples (no. 1: 0 Gy, no. 2: 1.2 Gy, no. 3: 3.5 Gy) were sent to each participant and the task was to culture samples, to prepare slides and to assess radiation doses based on the observed dicentric yields from 50 manually or 150 semi-automatically scored metaphases (triage mode scoring). Approximately two-thirds of the participants applied calibration curves from irradiations with γ rays and about 1/3 from irradiations with X rays with varying energies. The categorization of the samples in clinically relevant groups corresponding to individuals that were unexposed/minimally (0-1 Gy), moderately (1-2 Gy) or highly exposed (>2 Gy) was successfully performed by all participants for sample no. 1 and no. 3 and by ≥74% for sample no. 2. However, while most participants estimated a dose of exactly 0 Gy for the sham-irradiated sample, the precise dose estimates of the samples irradiated with doses >0 Gy were systematically higher than the corresponding reference doses and showed a median deviation of 0.5 Gy (sample no. 2) and 0.95 Gy (sample no. 3) for manual scoring. By converting doses estimated based on γ-ray calibration curves to X-ray doses of a comparable mean photon energy as used in this exercise, the median deviation decreased to 0.27 Gy (sample no. 2) and 0.6 Gy (sample no. 3). The main aim of biological dosimetry in the case of a large-scale event is the categorization of individuals into clinically relevant groups, to aid clinical decision making. This task was successfully performed by all participants for the 0 Gy and 3.5 Gy samples and by 74% (manual scoring) and 80% (semiautomatic scoring) for the 1.2 Gy sample. Due to the accuracy of the dicentric chromosome assay and the high number of participating laboratories, a systematic shift of the dose estimates could be revealed. Differences in radiation quality (X ray vs. γ ray) between the test samples and the applied dose effect curves can partly explain the systematic shift. There might be several additional reasons for the observed bias (e.g., donor effects, transport, experimental conditions or the irradiation setup) and the analysis of these reasons provides great opportunities for future research. The participation of laboratories from countries around the world gave the opportunity to compare the results on an international level.

Management of difficult bile duct stones and indeterminate bile duct structures: Reduced ERCP radiation exposure with adjunct use of digital single-operator cholangioscopy.

INTRODUCTION: Endoscopic Retrograde Cholangio-Pancreatography (ERCP) is an well-established endoscopic procedure for the management of biliary diseases. The use of fluoroscopy during ERCP has often raised concerns regarding potential risks from radiation exposure, particularly in complex cases. We investigated whether a new digital single-operator cholangioscopy (D-SOC) system, used adjunctively to ERCP, actually reduces patient radiation exposure. MATERIALS AND METHODS: We retrospectively analyzed a prospective database (April 2016 to October 2018) including consecutive patients who underwent successful management of difficult-to-treat biliary stones or indeterminate biliary strictures by using either conventional ERCP (ERCP cohort) or ERCP in conjunction with D-SOC (ERCP/D-SOC cohort). The overall patient radiation exposure outcomes were compared in terms of Kerma Area Product (KAP), Fluoroscopy time (T) and the total number of films (F). RESULTS: Overall, 47 patients (mean 71.8 years, 59.6% males) were included (ERCP cohort = 29, ERCP/D-SOC cohort = 18), referred either for difficult bile duct stones (n = 36) or indeterminate biliary strictures (n = 11). The median KAP, T and F in the ERCP/D-SOC cohort were 12.3 Gycm2, 3.7 min and 4 films respectively, compared with 52.1 Gycm2, 8.4 min, and 5 films respectively in the ERCP cohort. Statistically significant differences (P = 0.0001) were found for KAP and T. CONCLUSIONS: Adjunct use of a digital cholangioscopy platform appears to significantly reduce radiation exposure in patients undergoing ERCP for the management of difficult bile stones or indeterminate biliary strictures.

Combined chemoradiotherapy with local microwave hyperthermia for treatment of T3N0 laryngeal carcinoma: a retrospective study with long-term follow-up.

The purpose of our study was to test the efficacy and toxicity of hyperthermia in conjunction with chemoradiotherapy for T3N0 laryngeal cancer. From 1997-2006, 25 patients diagnosed with T3N0 laryngeal carcinoma who denied laryngectomy were selected for this retrospective study. Patients received a total dose of 70 Gy (2 Gy per fraction, 5 days per week) in combination with 6 weekly sessions of hyperthermia, in addition to weekly cisplatin chemotherapy. The hyperthermia device was operated as a 433 MHz microwave heating with water loaded and water-cooled waveguides. The temperature was monitored subcutaneously in the skin under the aperture of the waveguide. The median follow-up was 60 months, while 23 of 25 patients (92%) presented complete response to treatment. The two patients that did not respond to thermoradiotherapy underwent total laryngectomy, and during follow-up were alive and free of disease. According to EORTC/RTOG criteria, toxicity was mild: three patients (12%) presented grade III, eight (32%) presented grade II and 14 (56%) presented grade I acute skin toxicity. Grade III laryngeal late toxicity (vocal cord malfunction due to severe oedema) was noted in two patients (8%) at 6-8 months post-thermo-chemoradiotherapy. Tmin was correlated (Spearman rho, p < 0.05) with response to treatment as well as with acute skin toxicity and laryngeal function. When a patient with T3N0 laryngeal carcinoma denies laryngectomy, an alternative treatment is combined thermo-chemoradiotherapy which seems to be effective and generally tolerable with radiation-induced skin toxicity and/or late side effects. A larger patient cohort is needed to confirm these results.

Microwave hyperthermia in conjunction with radiotherapy in superficial tumours: correlation of thermal parameters with tumour regression / Hipertermia de microonda de conjunto con radioterapia en los tumores superficiales: correlación de los parámetros térmicos con la regresión del tumor

OBJECTIVE: The aim of the present study is to evaluate the correlation between the thermal parameters of hyperthermia and the clinical outcome in patients with superficial tumours. METHODS: In this study, 20 patients were included with either submandibular lymph nodes from head and neck cancer, or breast cancer relapses post-mastectomy. They were treated with radiation in combination with one session of433 MHz microwave hyperthermia (1 hour, 42.5 ºC-46 ºC). The dose of irradiation ranged from 54 to 60 Gy. The thermal parameters calculated were the minimum volume temperature, the maximum volume temperature and the time interval where the volume temperature was greater than 44 ºC. RESULTS: All patients responded positively to the combined treatment and 60% of the patients showed a complete response. Of the three parameters tested, the only parameter that was found to correlate with the reduction of the tumour diameter was the time with volume temperatures greater than 44 ºC (p < 0.001, Spearman rho). No moderate toxicity was observed. CONCLUSION: Microwave heating should be over 44 ºC for favourable treatment response, when combined with radiotherapy. More patients are needed to confirm the above results.

OJETIVO: El objetivo del presente estudio es evaluar la correlación entre los parámetros térmicos de la hipertermia y el resultado clínico en pacientes con tumores superficiales. MÉTODO: En este estudio, se incluyeron 20 pacientes con ganglios linfáticos submandibulares de cáncer de cabeza y cuello, o post-mastectomía por recidivas de cáncer de mama. Los pacientes fueron tratados con radiación en combinación con una sesión de hipertermia de microondas de 433 MHz (1 hora, 42.5 ºC-46 ºC). La dosis de irradiación osciló entre 54 y 60 Gy. Los parámetros térmicos calculados fueron la temperatura de volumen mínimo, la temperatura de volumen máximo y el intervalo de tiempo donde el volumen de la temperatura fue superior a 44 ºC. RESULTADOS: Todos los pacientes respondieron positivamente al tratamiento combinado y el 60% de los pacientes demostrados una respuesta completa. De los tres parámetros probados, el único parámetro que se comprobó que se correlaciona con la reducción del diámetro del tumor fue el tiempo con temperaturas de volumen superiores a 44 ºC (p < 0.001, rho de Spearman). No se observó ninguna toxicidad moderada. CONCLUSIÓN: Calentamiento por microondas debe estar por encima de 44 ºC para que la respuesta sea favorable al tratamiento en combinación con radioterapia. Se requieren más pacientes para confirmar los resultados anteriores.

Radiotherapy in conjunction with superficial and intracavitary hyperthermia for the treatment of solid tumors: survival and thermal parameters

Hyperthermia is an effective modality for the treatment of cancer, which is mainly used in conjunction with radiotherapy as this combined treatment offers a better clinical outcome. There are many ways that hyperthermia can be applied and depends on the kind of tumor of the patients. The great advantage of this method is that it is tolerable for the majority of patients without severe toxicity. Many clinical trials have been realized in order to prove that hyperthermia in addition to radiotherapy offers an advantage in the survival and local control of patients in comparison to radiotherapy alone. Many studies have also investigated if exists any correlation between the thermal parameters of hyperthermia and the clinical outcome. This is a review of these studies and it concerns superficial hyperthermia for superficial tumors-melanoma, head and neck, breast cancer-and intracavitary hyperthermia for rectal cancer, esophageal cancer and prostate carcinoma (AU)

Radiotherapy in conjunction with superficial and intracavitary hyperthermia for the treatment of solid tumors: survival and thermal parameters.

Hyperthermia is an effective modality for the treatment of cancer, which is mainly used in conjunction with radiotherapy as this combined treatment offers a better clinical outcome. There are many ways that hyperthermia can be applied and depends on the kind of tumor of the patients. The great advantage of this method is that it is tolerable for the majority of patients without severe toxicity. Many clinical trials have been realized in order to prove that hyperthermia in addition to radiotherapy offers an advantage in the survival and local control of patients in comparison to radiotherapy alone. Many studies have also investigated if exists any correlation between the thermal parameters of hyperthermia and the clinical outcome. This is a review of these studies and it concerns superficial hyperthermia for superficial tumors-melanoma, head and neck, breast cancer-and intracavitary hyperthermia for rectal cancer, esophageal cancer and prostate carcinoma.

Microwave hyperthermia in conjunction with radiotherapy in superficial tumours: correlation of thermal parameters with tumour regression.

OBJECTIVE: The aim of the present study is to evaluate the correlation between the thermal parameters of hyperthermia and the clinical outcome in patients with superficial tumours. METHODS: In this study, 20 patients were included with either submandibular lymph nodes from head and neck cancer, or breast cancer relapses post-mastectomy. They were treated with radiation in combination with one session of 433 MHz microwave hyperthermia (1 hour, 42.5 °C-46 °C). The dose of irradiation ranged from 54 to 60 Gy. The thermal parameters calculated were the minimum volume temperature, the maximum volume temperature and the time interval where the volume temperature was greater than 44 °C. RESULTS: All patients responded positively to the combined treatment and 60% of the patients showed a complete response. Of the three parameters tested, the only parameter that was found to correlate with the reduction of the tumour diameter was the time with volume temperatures greater than 44 °C (p < 0.001, Spearman rho). No moderate toxicity was observed. CONCLUSION: Microwave heating should be over 44 °C for favourable treatment response, when combined with radiotherapy. More patients are needed to confirm the above results.