Salvage I-125 brachytherapy for locally-recurrent prostate cancer after radiotherapy.

PURPOSE: Retrospective, single-institution analysis of clinical outcomes and treatment-related toxicity in patients treated with salvage I-125 low-dose rate (LDR) brachytherapy (BT) for locally-recurrent prostate cancer after radiotherapy. MATERIALS AND METHODS: Between 2008 and 2018, 30 patients with biopsy-confirmed prostate cancer recurrence underwent salvage treatment with I-125 LDR-BT. Of these 30 patients, 14 were previously treated with primary external beam radiotherapy (EBRT; median dose, 73 Gy) and 16 with primary I-125 LDR-BT (145 Gy and 160 Gy in 14 and 2 cases, respectively). At seed implantation, the mean age was 75.8 years, with a median Gleason score of 7 and pre-salvage PSA of <10 ng/mL. Six patients received androgen deprivation therapy for six months after relapse diagnosis. The prescribed salvage I-125 BT dose to the gland was 120-130 Gy, with dose restrictions of Dmax <135% (urethra) and <100% (rectum). Toxicity was evaluated according to the CTCAE scale (v4.0). RESULTS: At a median follow-up of 45 months, the biochemical recurrence-free survival rates at 1, 3 and 5 years were 86.7%, 56.7% and 53.3%, respectively. Overall survival at 5 years was 87%. On the multivariate analysis, two variables were significant predictors of recurrence: PSA at relapse and nadir PSA post-salvage. Grade 3 genitourinary toxicity was observed in 5 patients (radiation-induced cystitis in 3 cases and urethral stenosis in 2) and G3 gastrointestinal toxicity in 3 patients (rectal bleeding). CONCLUSION: Salvage therapy with I-125 brachytherapy is a safe and effective treatment option for locally-recurrent prostate cancer in previously-irradiated patients. High pre-salvage PSA and post-salvage nadir PSA values were significantly associated with a worse disease control after salvage I-125 LDR-BT. In well-selected patients, I-125 LDR-BT is comparable to other salvage therapies in terms of disease control and toxicity. However, more research is needed to determine the optimal management of locally-recurrent prostate cancer.

Impact of real-time, dose-escalated permanent seed implant brachytherapy in intermediate-risk prostate cancer.

PURPOSE: To retrospectively evaluate biochemical control and toxicity in patients who underwent 125I seed brachytherapy (BT) for intermediate-risk prostate cancer (PCa). MATERIALS AND METHODS: Between January 2004-December 2014, 395 patients with intermediate-risk PCa underwent 125I BT. Of these, 117 underwent preoperative planning (PP; 145 Gy) and 278 real-time intraoperative preplanning (IoP; 160 Gy). All patients were followed for ≥ 6 months (> 5 years in 48% of patients and > 7 years in 13%). Median follow-up was 59 months. RESULTS: Biochemical relapse-free survival (BRFS) rates at 5 and 8 years were, respectively, 91.7% and 82.1%. By treatment group, the corresponding BRFS rates were 93.5% and 90% for IoP and 89% and 76.8% for PP. The maximum dose to the urethra remained unchanged (217 Gy) despite the dose escalation (from 145 to 160 Gy), without any significant increase in treatment-related toxicity (p = 0.13). Overall toxicity outcomes in the series were excellent, with only 3 cases (0.76%) of grade 3 genitourinary toxicity. CONCLUSION: The real-time intraoperative planning technique at 160 Gy yields better biochemical controls than the preoperative planning technique at 145 Gy. Dose escalation did not increase urinary toxicity. The excellent results obtained with the IoP BT technique support its use as the first treatment option in this patient population.

Peripheral dose around a mobile linac for intraoperative radiotherapy: radiation protection aspects.

The aim of this work is to analyse the scattered radiation produced by the mobile accelerator Mobetron 1000. To do so, detailed Monte Carlo simulations using two different codes, Penelope2008 and Geant4, were performed. Measurements were also done. To quantify the attenuation due to the internal structures, present in the accelerator head, on the scattered radiation produced, some of the main structural shielding in the Mobetron 1000 has been incorporated into the geometry simulation. Results are compared with measurements. Some discrepancies between the calculated and measured dose values were found. These differences can be traced back to the importance of the radiation component due to low energy scattered electrons. This encouraged us to perform additional calculations to separate the role played by this component. Ambient dose equivalent, H*(10), outside of the operating room (OR) has been evaluated using Geant4. H*(10) has been measured inside and outside the OR, being its values compatible with those reported in the literature once the low energy electron component is removed. With respect to the role played by neutrons, estimations of neutron H*(10) using Geant4 together with H*(10) measurements has been performed for the case of the 12 MeV electron beam. The values obtained agree with the experimental values existing in the literature, being much smaller than those registered in conventional accelerators. This study is a useful tool for the clinical user to investigate the radiation protection issues arising with the use of these accelerators in ORs without structural shielding. These results will also enable to better fix the maximum number of treatments that could be performed while insuring adequate radiological protection of workers and public in the hospital.

Leukemia Cutis: A Report of 17 Cases and a Review of the Literature. / Leucemia cutis. Serie de 17 casos y revisión de la literatura.

Dermatologic manifestations of leukemia can be both specific and nonspecific (e.g., opportunistic infections, purpura and ecchymosis, Sweet syndrome). Leukemia cutis refers to the infiltration of the skin with neoplastic leukocytes and its early diagnosis has important prognostic implications. We report on 17 cases of leukemia cutis seen in our department between 1994 and 2014 and describe the characteristics of the patients (age, sex, medical history), the morphology of the lesions, and associations with systemic disease. Most of the patients were male and the most common associated malignancy was acute myeloid leukemia. The most frequent dermatologic manifestations were nodules or erythematous papules on the limbs. We describe our experience with the diagnosis and management of leukemia cutis over a period of 20 years and emphasize the importance of clinical signs in the early diagnosis of this condition.

Evaluation of lens absorbed dose with Cone Beam IGRT procedures.

The purpose of this work is to evaluate the absorbed dose to the eye lenses due to the cone beam computed tomography (CBCT) system used to accurately position the patient during head-and-neck image guided procedures. The on-board imaging (OBI) systems (v.1.5) of Clinac iX and TrueBeam (Varian) accelerators were used to evaluate the imparted dose to the eye lenses and some additional points of the head. All CBCT scans were acquired with the Standard-Dose Head protocol from Varian. Doses were measured using thermoluminescence dosimeters (TLDs) placed in an anthropomorphic phantom. TLDs were calibrated at the beam quality used to reduce their energy dependence. Average dose to the lens due to the OBI systems of the Clinac iX and the TrueBeam were 0.71 ± 0.07 mGy/CBCT and 0.70 ± 0.08 mGy/CBCT, respectively. The extra absorbed dose received by the eye lenses due to one CBCT acquisition with the studied protocol is far below the 500 mGy threshold established by ICRP for cataract formation (ICRP 2011 Statement on Tissue Reactions). However, the incremental effect of several CBCT acquisitions during the whole treatment should be taken into account.

Air-kerma evaluation at the maze entrance of HDR brachytherapy facilities.

In the absence of procedures for evaluating the design of brachytherapy (BT) facilities for radiation protection purposes, the methodology used for external beam radiotherapy facilities is often adapted. The purpose of this study is to adapt the NCRP 151 methodology for estimating the air-kerma rate at the door in BT facilities. Such methodology was checked against Monte Carlo (MC) techniques using the code Geant4. Five different facility designs were studied for (192)Ir and (60)Co HDR applications to account for several different bunker layouts.For the estimation of the lead thickness needed at the door, the use of transmission data for the real spectra at the door instead of the ones emitted by (192)Ir and (60)Co will reduce the lead thickness by a factor of five for (192)Ir and ten for (60)Co. This will significantly lighten the door and hence simplify construction and operating requirements for all bunkers.The adaptation proposed in this study to estimate the air-kerma rate at the door depends on the complexity of the maze: it provides good results for bunkers with a maze (i.e. similar to those used for linacs for which the NCRP 151 methodology was developed) but fails for less conventional designs. For those facilities, a specific Monte Carlo study is in order for reasons of safety and cost-effectiveness.

[Analysis of left ventricular diastolic function using magnetic resonance imaging]. / Análisis de la función diastólica del ventrículo izquierdo mediante resonancia magnética.

Heart failure is not always due to an alteration in systolic function, and a diastolic dysfunction could explain many cases of heart failure with a normal systolic function. Diastolic function depends on the left ventricular filling capacity to ensure a normal stroke volume. It is routinely measured with transthoracic echocardiography, as it is an easily accessible non-invasive test. The MRI, using flow sequences, shows good agreement with the echocardiography, analysing the diastolic function in a practical way, by the flow into the mitral valve and pulmonary veins. In this sense, the analysis of diastolic function should be added as part of a routine cardiac MR examination.

Handgrip strength and respiratory disease mortality: Longitudinal analyses from SHARE.

BACKGROUND: While the association between handgrip strength and all-cause mortality is more deeply explored, no previous studies have been specifically focused on handgrip strength and respiratory disease mortality. The purpose of the study was to investigate the association between handgrip strength and respiratory disease mortality in a large representative sample. METHODS: Individuals aged 50 or over from 27 European countries and Israel participated in this longitudinal study. Data on handgrip strength and all-cause and respiratory disease mortality were retrieved from the Survey of Health, Ageing and Retirement in Europe (SHARE) waves 1, 2, 4, 5, 6 and 7. We estimated the sub hazard ratios (SHRs) for respiratory disease mortality using a Fine-Gray sub-distribution method with both time-varying exposure and covariates and mortality due to other causes as competing risk. Furthermore, we assessed dose-response associations of handgrip strength (modelled as a continuous exposure) with respiratory disease mortality using restricted cubic splines and estimated hazard ratios (HRs). RESULTS: We included 60,883 men and 74,904 women with a mean age of 63.6 (SD 9.7) years at study entry. During a median (interquartile range) of 7.4 years of follow-up 565 (0.4%) participants died due to respiratory diseases. The increase of 1 single kg of handgrip strength showed a 6% incidence reduction on respiratory disease mortality (SHR, 0.94; 95%CI, 0.92-0.96) after adjusting for potential confounders. Furthermore, each kg increase of handgrip strength reduced respiratory disease mortality risk in a dose-response fashion and a significant threshold for values of 41 kg (HR, 0.49; 95%CI, 0.26-0.92) and higher was identified. CONCLUSIONS: Higher handgrip strength is associated with lower mortality due to respiratory disease. Intervention studies are needed to determine whether strength training in respiratory disease patients can prevent premature mortality.

Consensus and recommendations on vaginal-cuff Brachytherapy of the Spanish Brachytherapy Groups of SEOR and SEFM.

PURPOSE/OBJECTIVE(S): On October 5, 2018, a meeting of the Spanish Society of Radiation Oncology (SEOR) Brachytherapy Group was held, in collaboration with the Spanish Society of Medical Physics (SEFM), with the aim of preparing a consensus document on postoperative vaginal-cuff brachytherapy (VCBT). MATERIALS/METHODS: A survey including 42 questions was sent to Spanish Radiation Oncology Centres before the meeting. The survey items included: experience in VCBT, technique indications, previous patient preparation, applicator type, implant procedure, computerized tomography (CT) simulation, definition of target volumes and organs at risk (OAR), dose prescription, fractionation, treatment planning, dosimetric parameters and constraints to OAR. Thirty-three centres answered the survey. Statistical analysis of the survey considered that there was consensus when there was ≥ 85% of agreement related to a survey item, otherwise an item with < 85% of agreement would be discussed during the meeting to reach consensus. RESULTS: The results of the survey are reported here. The mean number of patients treated per centre in 2017 was 52 ± 41 (range 7-175), and the mean number of procedures per centre was 175 ± 150 (range 24-701).There was consensus on: the indications, applicator type, the OAR to be considered, the prescription point, standardisation and dosimetric quality parameters. There was no consensus on: patient preparation for the implant, the need for performing CT simulation and the frequency, the length of the vagina to be treated, if CTV should be delimited, the definition of the clinical target volume, fractionation, overall EQD2, active source length, separation between dwelling stepping source positions, if considering the uniformity/maximum values for dwelling stepping sources, the optimization mode, and the limiting doses to the OAR. After presenting the results of the survey, the consensus meeting discussion focused on the issues for which there was no consensus. CONCLUSION: A consensus document on postoperative VCBT of the Spanish Brachytherapy Groups of SEOR-SEFM was elaborated.

SEOR SBRT-SG survey on SRS/SBRT dose prescription criteria in Spain.

AIM: Stereotactic body radiotherapy (SBRT) and stereotactic radiosurgery (SRS) are essential tools in radiation oncology. In Spain, the use of these techniques continues to grow as older linear accelerators (linacs) are replaced with modern equipment. However, little is known about inter-centre variability in prescription and dose heterogeneity limits. Consequently, the SBRT-Spanish Task Group (SBRT-SG) of the Spanish Society of Radiation Oncology (SEOR) has undertaken an initiative to assess prescription and homogeneity in SRS/SBRT treatment. In the present study, we surveyed radiation oncology (RO) departments to obtain a realistic overview of prescription methods used for SBRT and SRS treatment in Spain. METHODS: A brief survey was developed and sent to 34 RO departments in Spain, mostly those who are members of the SEOR SBRT-SG. The survey contained seven questions about the specific prescription mode, dose distribution heterogeneity limits, prescription strategies according to SRS/SBRT type, and the use of IMRT-VMAT (Intensity Modulated Radiation Therapy-Volumetric Modulated Arc Therapy). RESULTS: Responses were received from 29 centres. Most centres (59%) used the prescription criteria D95% ≥ 100%. Accepted dose heterogeneity was wide, ranging from 107 to 200%. Most centres used IMRT-VMAT (93%). CONCLUSIONS: This survey about SRS/SBRT prescription and dose heterogeneity has evidenced substantial inter-centre variability in prescription criteria, particularly for intended and accepted dose heterogeneity. These differences could potentially influence the mean planning target volume dose and its correlation with treatment outcomes. The findings presented here will be used by the SEOR SBRT-SG to develop recommendations for SRS/SBRT dose prescription and heterogeneity.

[Applications of noninvasive mechanical ventilation in anesthesiology and postanesthesia recovery care]. / Aplicaciones de la ventilación mecánica no invasiva en anestesiologáa y reanimación.

Noninvasive ventilation (NIV) can be useful to anesthesiologists working in critical care units, postanesthesia recovery units, operating theaters, or other settings. NIV can help in situations of acute respiratory failure or serve as a preventive measure in patients undergoing interventions under local-regional anesthesia or diagnostic or therapeutic procedures requiring sedation. Successful NIV depends on adequately trained health personnel and the proper choice of material (interfaces, respirators, etc.) for each setting where this modality is used.

Are Moderate and Vigorous Leisure-Time Physical Activity Associated With Musculoskeletal Pain? A Cross-Sectional Study Among 981 Physical Therapists.

PURPOSE: Musculoskeletal pain (MP) is common among workers, especially for health-care professionals. Paradoxically, many of those rehabilitating patients for pain-that is, physical therapists (PTs)-also have pain. Adequate levels of physical activity are recommended for cardiovascular and musculoskeletal health. However, the association between physical activity and MP among PTs remains unknown. This study aims to determine the association between moderate and vigorous leisure-time physical activity levels and MP in PTs. DESIGN: Cross-sectional study. SETTING: Workplace. PARTICIPANTS: Nine hundred eighty-one PTs. MEASURES: Data on MP and leisure-time physical activity were collected using an online survey. ANALYSIS: The odds for having lower level of MP as a function of physical activity were estimated using binary logistic regression controlled for various confounders. RESULTS: Performing ≥75 min/week of vigorous leisure-time physical activity increased the odds of experiencing lower levels of neck-shoulder pain (odds ratio = 1.43, 95% confidence interval, 1.05-1.94). No association was found neither between vigorous nor between moderate leisure-time physical activity and MP in the arm-hand or back. CONCLUSION: Performing ≥75 min/week of vigorous leisure-time physical activity is associated with lower levels of MP in neck and shoulders among PTs. No associations were found between vigorous or moderate leisure-time physical activity and MP in arm-hand and back.

100% peer review in radiation oncology: is it feasible?

PURPOSE: Peer review has been proposed as a strategy to ensure patient safety and plan quality in radiation oncology. Despite its potential benefits, barriers commonly exist to its optimal implementation in daily clinical routine. Our purpose is to analyze peer-review process at our institution. METHODS AND MATERIALS: Based on our group peer-review process, we quantified the rate of plan changes, time and resources needed for this process. Prospectively, data on cases presented at our institutional peer-review conference attended by physicians, resident physicians and physicists were collected. Items such as time to present per case, type of patient (adult or pediatric), treatment intent, dose, aimed technique, disease location and receipt of previous radiation were gathered. Cases were then analyzed to determine the rate of major change, minor change and plan rejection after presentation as well as the median time per session. RESULTS: Over a period of 4 weeks, 148 cases were reviewed. Median of attendants was six physicians, three in-training-physicians and one physicist. Median time per session was 38 (4-72) minutes. 59.5% of cases presented in 1-4 min, 32.4% in 5-9 min and 8.1% in ≥ 10 min. 79.1% of cases were accepted without changes, 11.5% with minor changes, 6% with major changes and 3.4% were rejected with indication of new presentation. Most frequent reason of change was contouring corrections (53.8%) followed by dose or fractionation (26.9%). CONCLUSION: Everyday group consensus peer review is an efficient manner to recollect clinical and technical data of cases presented to ensure quality radiation care before initiation of treatment as well as ensuring department quality in a feedback team environment. This model is feasible within the normal operation of every radiation oncology Department.

Monte Carlo study of the dose rate distributions for the Ir2.A85-2 and Ir2.A85-1 Ir-192 afterloading sources.

The two most commonly used modalities of cancer treatment in clinical brachytherapy practice today are high dose rate (HDR) and pulsed dose rate (PDR) brachytherapy. In a clinical treatment, quality dose rate distribution data sets of the brachytherapy sources are required for each source model. The purpose of this study is to obtain detailed dose rate distributions around the new BEBIG HDR and PDR Ir-192 brachytherapy sources. These distributions will then be used as input data in the treatment planning systems dedicated to brachytherapy and its calculations can be verified. The Monte Carlo method was used to obtain the dose rate distributions around the sources studied, taking into account the AAPM-ESTRO recent recommendations. A complete dosimetric data set for the BEBIG Ir-192 HDR and PDR sources, types Ir2.A85-2 and Ir2.A85-1, were obtained. This dosimetric data set is composed of the TG-43 dosimetric functions and parameters and along-away dose rate table to facilitate quality control of treatment planning systems.

Design and evaluation of a HDR skin applicator with flattening filter.

The purposes of this study are: (i) to design field flattening filters for the Leipzig applicators of 2 and 3 cm of inner diameter with the source traveling parallel to the applicator contact surface, which are accessories of the microSelectron-HDR afterloader (Nucletron, Veenendaal, The Netherlands). These filters, made of tungsten, aim to flatten the heterogeneous dose distribution obtained with the Leipzig applicators. (ii) To estimate the dose rate distributions for these Leipzig+filter applicators by means of the Monte Carlo (MC) method. (iii) To experimentally verify these distributions for prototypes of these new applicators, and (iv) to obtain the correspondence factors to measure the output of the applicators by the user using an insert into a well chamber. The MC GEANT4 code has been used to design the filters and to obtain the dose rate distributions in liquid water for the two Leipzig+filter applicators. In order to validate this specific application and to guarantee that realistic source-applicator geometry has been considered, an experimental verification procedure was implemented in this study, in accordance with the updated recommendations of the American Association of Physicists in Medicine Task Group No. 43 U1 Report. Thermoluminescent dosimeters, radiochromic film, and a pin-point ionization chamber in a plastic [polymethylmethacrylate (PMMA)] phantom were used to verify the MC results for the two applicators of a microSelectron-HDR afterloader with the mHDR-v2 source. To verify the output of the Leipzig +filter applicators, correspondence factors were deduced for the well chambers HDR100-plus (Standard Imaging, Inc., Middleton, WI) and TM33004 (PTW, Freiburg, Germany) using a specific insert for both applicators. The doses measured in the PMMA phantom agree within experimental uncertainties with the dose obtained by the MC calculations. Percentage depth dose and off-axis profiles were obtained normalized at a depth of 3 mm along the central applicator axis in a cylindrical 20 x 20 cm water phantom. A table of output factors, normalized to 1 U of source air kerma strength at this depth, is presented. Correspondence factors were obtained for the two well chambers considered. The matrix data obtained in the MC simulation with a grid separation of 0.5 mm has been used to build a data set in a convenient format to model these distributions for routine use with a brachytherapy treatment planning system.

Dosimetric characterization of Ir-192 LDR elongated sources.

Ir-192 wires have been used in low-dose-rate brachytherapy for many years. Commercially available treatment planning systems approximate the dose rate distribution of the straight or curved wires applying the superposition principle using one of the following methods: (i) The wire is modeled as a set of point sources, (ii) the wire is modeled as a set of small straight segment wires, (iii) the values of the parameters and functions of the American Association of Physicists in Medicine (AAPM) Task Group 43 protocol are obtained for wire lengths between 3 and 7 cm assuming some simplifications. The dose rate distributions obtained using these methods for linear wires of different lengths and U-shaped wires present significant deviations compared to those obtained by Monte Carlo. In the present study we propose a new method to model 192Ir wires of any length and shape, named the Two Lengths based Segmented method. This method uses the formalism stated in the AAPM Task Group 43 protocol for two straight wires only, 0.5 and 1 cm, to obtain the dose rate distribution around wires of any length (down to 0.3 cm and up to 10 cm) improving on the results of the aforementioned ones. This method can easily be applied to dose calculations around other wires, such as Pd-103 ones.

Radiation transmission data for radionuclides and materials relevant to brachytherapy facility shielding.

To address the limited availability of radiation shielding data for brachytherapy as well as some disparity in existing data, Monte Carlo simulation was used to generate radiation transmission data for 60Co, 137CS, 198Au, 192Ir 169Yb, 170Tm, 131Cs, 125I, and 103pd photons through concrete, stainless steel, lead, as well as lead glass and baryte concrete. Results accounting for the oblique incidence of radiation to the barrier, spectral variation with barrier thickness, and broad beam conditions in a realistic geometry are compared to corresponding data in the literature in terms of the half value layer (HVL) and tenth value layer (TVL) indices. It is also shown that radiation shielding calculations using HVL or TVL values could overestimate or underestimate the barrier thickness required to achieve a certain reduction in radiation transmission. This questions the use of HVL or TVL indices instead of the actual transmission data. Therefore, a three-parameter model is fitted to results of this work to facilitate accurate and simple radiation shielding calculations.

Recommendations of the Spanish brachytherapy group (GEB) of Spanish Society of Radiation Oncology (SEOR) and the Spanish Society of Medical Physics (SEFM) for high-dose rate (HDR) non melanoma skin cancer brachytherapy.

Clinical indications of brachytherapy in non-melanoma skin cancers, description of applicators and dosimetry recommendations are described based on the literature review, clinical practice and experience of Spanish Group of Brachytherapy and Spanish Society of Medical Physics reported in the XIV Annual Consensus Meeting on Non Melanoma Skin Cancer Brachytherapy held in Benidorm, Alicante (Spain) on October 21st, 2016. All the recommendations for which consensus was achieved are highlighted in blue. Regular and small surfaces may be treated with Leipzig, Valencia, flap applicators or electronic brachytherapy (EBT). For irregular surfaces, customized molds or interstitial implants should be employed. The dose is prescribed at a maximum depth of 3-4 mm of the clinical target volume/planning target volume (CTV/PTV) in all cases except in flaps or molds in which 5 mm is appropriate. Interstitial brachytherapy should be used for CTV/PTV >5 mm. Different total doses and fraction sizes are used with very similar clinical and toxicity results. Hypofractionation is very useful twice or 3 times a week, being comfortable for patients and practical for Radiotherapy Departments. In interstitial brachytherapy 2 fractions twice a day are applied.