Search

Routine in vivo dosimetry is well established in external beam radiotherapy; however, it is restricted mainly to detection of gross errors in high-dose-rate (HDR) brachytherapy due to complicated measurements in the field of steep dose gradients in the vicinity of radioactive source and high uncertainties. The results of in vivo dose measurements using TLD 100 mini rods and TLD 'pin worms' in catheter-based HDR brachytherapy are provided in this paper alongside with their comparison with corresponding dose values obtained using calculation algorithm of the treatment planning system. Possibility to perform independent verification of treatment delivery in HDR brachytherapy using TLDs is discussed. [ABSTRACT FROM AUTHOR]

Brachytherapy is an effective treatment in the curative management of prostate and gynaecological cancers. With advances in technology, brachytherapy has increased in complexity in recent years. Human error, equipment malfunction, patient organ motion and radioactive source displacement can result in substantial deviation of delivered dose from planned dose. To limit adverse clinical outcomes, adequate steps to improve the robustness of pathway processes, ensure the implementation of appropriate treatment margins and confirm the delivered dose must be considered. In vivo dosimetry is one such method of dose validation which, if implemented appropriately within clinical practice, is an attractive technique for reducing dosimetric uncertainties and identifying potential errors. This review aims to describe the dosimetric uncertainties and potential errors associated with brachytherapy, the potential for in vivo dosimetry in adaptive brachytherapy as a key method of dose validation, and the clinical considerations and future directions of in vivo dosimetry. Advances in knowledge: This paper describes the potential role for in vivo dosimetry in the reduction of uncertainties in pelvic brachytherapy, the pertinent factors for consideration in clinical practice, and the future potential for in vivo dosimetry in the personalisation of brachytherapy. [ABSTRACT FROM AUTHOR]

Effective dose equivalent (EDE), and effective dose (ED) for coronary and femoral Intravascular brachytherapy (IVBT) procedures involving a 370 GBq (10 Ci) HDR 192Ir gamma source are tabulated. MIRD stylised models and the MCNP Monte Carlo code were used for the calculations. For coronary irradiation, the normalised EDE is 0.18 mSv (GBq min)-1 and the ED is 0.056 mSv (GBq min)-1. For femoral IVBT, the normalised EDE is 0.01629 mSv (GBq min)-1 and the ED is 0.01 195 mSv (GBq min)-1. Although the medical benefits to a patient undergoing IVBT are often significant and justified, patient doses are high compared with dose limits for radiation protection purposes. As IVBT is becoming a routine procedure, data in this paper could be useful to manage the procedures efficiently. [ABSTRACT FROM AUTHOR]

The article presents a study which models gold nanoparticle (GNPs)-eluting spacer degradation during brachytherapy application with in situ dose painting. The study results show a significant delay of GNP diffusion in the tumour in comparison to burst release assumed in previous studies. The results highlight the need to account for the slow release of GNPs from spacers and polymer biodegradation in research development of the GNPeluting spacers.

This paper describes the establishment by the Institute of Nuclear Energy Research (INER, Taiwan) of the reference air kerma rate (RAKR) calibration standard for measurement of high-dose rate (HDR) 192Ir brachytherapy source strength. A bilateral comparison has been made in the RAKR standards for HDR 192Ir brachytherapy sources at the INER and Physikalisch-Technische Bundesanstalt (PTB, Germany) and the measurement difference was within the overall standard uncertainty and showed good agreement between the two calibration standard systems established at the INER and the PTB. Besides, INER also worked with 20 domestic hospitals to organise an on-site measurement comparison programme to explore the status of HDR 192Ir brachytherapy source strength determination in Taiwan. The comparison results presented the ratios of RAKR with vendor values, as determined by INER and hospitals from the programme. The ratios fall in all cases within the ±3 % guaranteed by the vendors for a coverage factor of k=2 or at 95 % confidence level. [ABSTRACT FROM PUBLISHER]

It has been postulated that the combination of intracavitary and interstitial brachytherapy (IC/IS) is effective and safe for large and irregularly shaped uterine cervical cancer patients. However, due to its invasiveness compared to conventional intracavitary brachytherapy (ICBT), it has to be said that the implementation speed of IC/IS is slow. Until now, there have been no guidelines for required equipment, human resources, and procedural guide focusing solely on IC/IS. The purpose of this guideline is to provide radiation oncologists and medical physicists who wish to start IC/IS with practical and comprehensive guidance for a safe IC/IS introduction and to help accelerate the spread of the utilization of IC/IS nationwide. This is the English translation of the Japanese IC/IS Guidelines, and it was created in an effort to share the Japanese approach to the management of locally advanced uterine cervical cancer worldwide. [ABSTRACT FROM AUTHOR]

In our previous prospective trial on accelerated hypofractionated concomitant radiochemotherapy (AHRT-CHT) for non-small-cell lung cancer (NSCLC), the incidence of grade ≥3 acute esophageal toxicity (AET) was similar to that reported for conventionally fractionated concomitant radiochemotherapy (CFRT-CHT), but its duration was prolonged. Thus, we aimed to compare the duration of grade ≥3 AET between AHRT-CHT and CFRT-CHT. Clinical data of 76 NSCLC patients treated with CFRT-CHT (60–66 Gy/2 Gy) during 2015–2020 were retrospectively compared with the data of 92 patients treated with AHRT-CHT (58.8 Gy/2.8 Gy) in the prospective trial. The maximum grade of AET, incidence, and duration of grade ≥3 AET were the end points. Univariate and multivariate analyses were applied to correlate clinical and treatment variables with these end points. Neither the maximum grade of AET (p = 0.71), nor the incidence of grade ≥3 AET (p = 0.87) differed between the two groups. The number of CHT cycles delivered (2 vs 1, p = 0.005) and higher esophagus mean BED (p = 0.009) were significant predictors for a higher maximum grade of AET; older age was a significant predictor for higher incidence of grade ≥3 AET (p = 0.03). The median duration of grade ≥3 AET in AHRT-CHT and CFRT-CHT group was 30 days (range 5-150) vs 7 days (range 3–20), respectively, p = 0.0005. In multivariate analysis, only the AHRT-CHT schedule (p=0.003) was a significant predictor for a longer duration of grade ≥3 AET. Despite similar incidence of grade ≥3 AET, its duration is significantly prolonged in NSCLC patients treated with AHRT-CHT compared to CFRT-CHT. Reporting only the rate of grade ≥3 AET in clinical trials may underestimate the real extent of the esophageal toxicity; its duration should also be routinely reported. [ABSTRACT FROM AUTHOR]

The main standard of care for locally advanced cervix carcinoma (LACC) is radiochemotherapy (RCT) followed by brachytherapy. A surgical approach may still be discussed based on pelvic MRI-derived residual tumour evaluation. As no interobserver agreement study has ever been conducted to our knowledge, the aim of the present study was to report on pelvic MRI accuracy and interobserver agreement in LACC. We carried out a retrospective study in a French university hospital. Medical records of all consecutive patients treated with curative intent for LACC by RCT followed by brachytherapy and completion pelvic surgery between January 2014 and January 2020 were reviewed. Local response was assessed through pelvis MRI and histological analysis after completion surgery. MRI data were independently evaluated by two radiologists with varying experience. The two main interobserving criteria we used were complete response and residual tumour. 23 patients fulfilled the inclusion criteria. Agreement between the junior and senior radiologist was moderate to strong. Indeed, regarding main criteria, κ was 0.65 for complete response and 0.57 for residual tumour. Interestingly, the present study shows a lower sensitivity whatever the radiologists than in the international literature. The present study highlights a low interobserver variability regarding pelvic MRI in the assessment of RCT followed by brachytherapy in LACC. Yet, sensitivity was lower than in literature. Radiology is part of treatment decision-making, the issue of heterogeneity regarding radiologists' training and experience to cancer (sensitivity and specificity) turns essential, so does MRI accuracy. [ABSTRACT FROM AUTHOR]

We aimed to investigate whether gold marker implantation in the tissue surrounding the prostate could accurately monitor setup errors during external beam radiation therapy (EBRT) following low-dose-rate (LDR) brachytherapy. Thirty-eight patients had confirmed intermediate- or high-risk prostate cancer and received EBRT following LDR brachytherapy. In >175 computed tomography imaging sessions, the average values of the weekly setup error during EBRT to the prostate centroid at the time of gold marker matching in the surrounding tissue of the prostate and pelvic bone matching were measured and then compared using the Wilcoxon signed-rank test. Gold marker matching in the surrounding tissue of the prostate estimated setup errors better than those estimated by bone matching (3D displacement = 2.7 ± 2.0 vs 3.8 ± 2.6 mm, P  < 0.01). Overall, the standard deviation of systematic (Σ) and random (σ) setup error was lower with gold marker matching than with bone matching (3D displacement = 1.8 and 1.1 mm vs 2.1 and 1.6 mm, respectively). With gold marker matching, the setup error of the position of the prostate centroid was smaller, and the optimal setup margin was lower than that with bone matching (2Σ + 0.7σ and 2.5Σ + 0.7σ of 3D displacement = 4.3 and 5.2 mm vs 5.3 and 6.4 mm, respectively). This high-precision radiotherapy approach placing gold markers in the surrounding tissue of the prostate can allow more accurate setup during EBRT following LDR brachytherapy. [ABSTRACT FROM AUTHOR]

The aim of the present study was to evaluate the clinical significance of the post-radiotherapy 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) response for detecting residual disease and predicting survival outcome in patients with nasopharyngeal cancer. We reviewed 143 patients with nasopharyngeal cancer who underwent 18F-FDG PET within 6 months after completion of radiotherapy between 2001 and 2012. 18F-FDG PET findings at the primary tumor (T–) and regional lymph nodes (N–) were separately assessed and considered negative [PET (–)] or positive [PET (+)] depending on the remaining focal increased uptake of 18F-FDG that was greater than that of the surrounding muscle or blood vessels. The standard of reference was histopathological confirmation or clinical/imaging follow-up. Overall survival (OS), distant metastasis-free survival (DMFS), and locoregional recurrence-free survival (LRRFS) rates were estimated from the date of the start of radiotherapy. The median follow-up period was 73 months (range, 9–182 months). Overall, 83 and 66% of patients achieved T–PET (-) and N–PET (-) responses, and the negative-predictive values (NPVs) for T– and N– were 100 and 99%, respectively. The sensitivity, specificity, and positive-predictive value were 100, 84, and 8% for T–, and 67, 80, and 7% for N–, respectively. The 5-year OS, DMFS, and LRRFS rates were 83, 83, and 87%, respectively, and patients with N–PET (+) with SUVmax >2.5 showed significantly inferior 5-year OS and DMFS rates than patients with N–PET (-) or N–PET (+) with SUVmax ≤2.5 (44 vs 86%, p = 0.004; 36 vs 85%, p < 0.001). In patients that have received definitive (chemo)radiotherapy for nasopharyngeal cancer, 18F-FDG PET within 6 months of completion of treatment has a high NPV for predicting residual disease and is prognostic for long-term treatment outcomes. Patients with remaining focal increased uptake of 18F-FDG at lymph nodes may benefit from more aggressive treatments, and further studies are needed to validate the clinical significance of post-radiotherapy 18F-FDG PET. We found that post-radiotherapy 18F-FDG PET findings have a high NPV for detecting residual disease and are a significant prognostic factor for treatment outcomes. [ABSTRACT FROM AUTHOR]

The purpose of this study is to investigate the dosimetric feasibility of delivering focal dose to multiparametric (mp) MRI-defined DILs in CT-based high-dose-rate (HDR) prostate brachytherapy with MR/CT registration and estimate its clinical benefit. We retrospectively investigated a total of 17 patients with mp-MRI and CT images acquired pre-treatment and treated by HDR prostate brachytherapy. 21 dominant intraprostatic lesions (DILs) were contoured on mp-MRI and propagated to CT images using a deformable image registration method. A boost plan was created for each patient and optimized on the original needle pattern. In addition, separate plans were generated using a virtually implanted needle around the DIL to mimic mp-MRI guided needle placement. DIL dose coverage and organ-at-rick (OAR) sparing were compared with original plan results. Tumor control probability (TCP) was estimated to further evaluate the clinical impact on the boost plans. Overall, optimized boost plans significantly escalated dose to DILs while meeting OAR constraints. The addition of mp-MRI guided virtual needles facilitate increased coverage of DIL volumes, achieving a V150 > 90% in 85 % of DILs compared with 57 % of boost plan without an additional needle. Compared with original plan, TCP models estimated improvement in DIL control by 28 % for patients with external-beam treatment and by 8 % for monotherapy patients. With MR/CT registration, the proposed mp-MRI guided DIL boost in CT-based HDR brachytherapy is feasible without violating OAR constraints, and indicates significant clinical benefit in improving TCP of DIL. It may represent a strategy to personalize treatment delivery and improve tumor control. This study investigated the feasibility of mp-MRI guided DIL boost in HDR prostate brachytherapy with CT-based treatment planning, and estimated its clinical impact by TCP and NTCP estimation. [ABSTRACT FROM AUTHOR]

The present study aimed to compare the dosages of target regions and organs at risk (OARs) in 3D intracavitary brachytherapy (ICBT) and conventional 2D ICBT for Chinese patients with cervical carcinoma. ICBT was performed in a total of 66 patients with Stage IB to IVA cervical carcinoma who had not received surgery but who had received whole-pelvic external-beam radiotherapy (EBRT). Plans for the 3D-ICBT and the conventional 2D-ICBT were individually designed for every patient. The dosages differences between the target regions and the OARs in patients with each of the various stages of cervical carcinoma were compared between the two ICBT plans. There was no significant difference in the dose at Point A between the two ICBT plans. However, the CTVhr-D90, CTVhr-D100 and CTVir-D90 in 3D-ICBT were much higher than in 2D-ICBT, especially in Stage IIB (P < 0.05). As compared with conventional 2D-ICBT, the dosages of DICRU and D2.0cm3 in the rectum/bladder, and D2.0cm3 in the sigmoid/small bowel were decreased significantly in 3D-ICBT (P < 0.05). For patients with Stage IIA, IIB and IIIB, the D2.0cm3 in the rectum/bladder was significantly reduced in 3D-ICBT (P < 0.05). It was demonstrated that, in Chinese patients, 3D-ICBT for cervical carcinoma could optimize the target coverage and reduce the dosages to the OARs compared with conventional 2D-ICBT. [ABSTRACT FROM AUTHOR]

Aim: This study systematically reviews the recent literature on the role of definitive radiotherapy (RT) in the management of vaginal cancer (VC) and presents comprehensive data on clinical outcomes and toxicity. Methods: The authors performed a literature search using PubMed (2007–2016) to identify all prospective and retrospective studies that have been published on RT in invasive VC. Results: Of the 199 identified studies, 13 met the inclusion criteria. All studies had a retrospective design. Overall, 793 patients (median, 45; range, 26–138) were included. A high heterogeneity was found across studies in terms of RT techniques, assessment criteria, and reported outcomes. The majority of the patients were treated with a combination of external beam RT and brachytherapy (74.2%). Acute and late grade ≥3 toxicity rates ranged from 0.0% to 24.4% (median, 8.7%) and from 0.0% to 22.5% (median, 12.8%), respectively. The 5‐year local control rates ranged between 39% and 79%. The 5‐year overall survival ranged between 34% and 71.0% (median, 63.5%). Early stage of the disease (International Federation of Gynecology and Obstetrics stages I–II vs. III–IV), small tumor size (<4 cm), previous hysterectomy, high pretreatment/treatment hemoglobin levels (≥12/12.5 mg/dL), and patients' age <70 or <64 years were correlated with better clinical outcomes. Conclusion: Only retrospective studies, in a limited number, have been published on RT in VC in the past decade, with significant heterogeneity in terms of treatment characteristic and evaluation criteria. Clinical results were strongly influenced by tumor stage. Prospective randomized studies are needed to improve patients' outcomes, especially in advanced‐stage disease. Implications for Practice: This study systematically reviews the recent literature on the role of definitive radiotherapy in the management of vaginal cancer and presents comprehensive data on clinical outcome and toxicity. The prognosis of patients is dismal, with a 5‐year overall survival of approximately 50%. Early stage of the disease, small tumor size, previous hysterectomy, high pretreatment/treatment hemoglobin levels, and patients' age were correlated with a better clinical outcome. A brachytherapy boost should be delivered, especially in patients with higher‐stage disease. The addition of concurrent weekly cisplatin should be considered in most patients, and transfusion should be used to maintain high hemoglobin levels. This systematic review provides an overview of the role of radiation therapy in the management of vaginal carcinoma and summarizes data on treatment outcome and toxicity. [ABSTRACT FROM AUTHOR]

The results of the comparison between SSDL-ININ and SSDL-CPHR (pilot laboratory) demonstrates the competence of the SSDL-ININ for the performance of the K ̇ R in 192Ir. The R ININ/CHPR ratio for the calibration coefficients is 0.989 ± 0.005. The comparison uses three SI-HDR 1000 - Plus as transfer chambers, series: A02423, A941755 and A973052. CPHR used a secondary standard PTW 3304 chamber, s/n 154, calibrated at PTB and ININ employed a secondary standard SI-90008 s/n A963391, calibrated at NPL. To determine K ̇ R ⁠, the SSDL-CPHR used the IAEA TEC-DOC-1274 and the SSDL-ININ used the IPEM (UK) code of practice. The latter uses a correction factor by source's geometry, k sg ⁠. The results show that both codes are equivalent; however, for the use of well chambers in the highlands or in locations with reduced atmospheric pressure, it is needed to apply an additional factor k ′ P ⁠, or, to design a well chamber with air-equivalent walls for the application of the conventional k PT ⁠. [ABSTRACT FROM AUTHOR]

The normal tissue complication probability (NTCP) is a measure for the estimated side effects of a given radiation treatment schedule. Here we use a stochastic logistic birth-death process to define an organspecific and patient-specific NTCP. We emphasize an asymptotic simplification which relates the NTCP to the solution of a logistic differential equation. This framework is based on simple modelling assumptions and it prepares a framework for the use of the NTCP model in clinical practice. As example, we consider side effects of prostate cancer brachytherapy such as increase in urinal frequency, urinal retention and acute rectal dysfunction. [ABSTRACT FROM AUTHOR]

Background: Guideline-concordant local therapy options for early breast cancer include lumpectomy plus whole breast irradiation (Lump+WBI), lumpectomy plus brachytherapy, mastectomy alone, mastectomy plus reconstruction, and, in older women, lumpectomy alone. We performed a comparative examination of each treatment's complications and cost to assess their relative values.Methods: Using the MarketScan database of younger women with private insurance and the SEER-Medicare database of older women with public insurance, we identified 105 211 women with early breast cancer diagnosed between 2000 and 2011. We used diagnosis and procedural codes to identify treatment complications within 24 months of diagnosis and compared complications by treatment using two-sided logistic regression. Mean total and complication-related cost, relative to Lump+WBI, were calculated from a payer's perspective and adjusted for differences in covariables using linear regression. All statistical tests were two-sided.Results: Lump+WBI was the most commonly used treatment. Mastectomy plus reconstruction was associated with nearly twice the complication risk of Lump+WBI (Marketscan: 54.3% vs 29.6%, relative risk [RR] = 1.87, 95% confidence interval [CI] = 1.82 to 1.91, P < .001; SEER-Medicare: 66.1% vs 37.6%, RR = 1.75, 95% CI = 1.69 to 1.82, P < .001) and was also associated with higher adjusted total cost (Marketscan: $22 481 greater than Lump+WBI; SEER-Medicare: $1748 greater) and complication-related cost (Marketscan: $9017 greater; SEER-Medicare: $2092 greater). Brachytherapy had modestly higher total cost and complications than WBI. Lumpectomy alone entailed lower cost and complications in the SEER-Medicare cohort only.Conclusions: Mastectomy plus reconstruction results in substantially higher complications and cost than other guideline-concordant treatment options for early breast cancer. These findings are relevant to patients evaluating their local therapy options and to value-based population health management. [ABSTRACT FROM AUTHOR]

Objective: Recently, a new catheter-based 32P brachytherapy source has been developed (College of Chemistry, Sichuan University) for use in high-dose-rate afterloader. This study presents the results of the dosimetric data of the Geant4 Monte Carlo (MC) simulation toolkit for this new 32P brachytherapy source. Methods: The new 32P source had dimensions of 0.50-cm length and 0.08-cm diameter and was encapsulated in teflon. In this study, we attempted to obtain dosimetric data for this new source, as required by the formalism proposed by the American Association of Physicists in Medicine reports TG60 and TG149. The source was located in a 30-cm radius theoretical sphere water phantom, and the absorbed dose of the source was calculated using MC code. Results: The dosimetric data included the reference absorbed dose rate, the radial dose function in the range of 0.10-0.50 cm at a longitudinal axis, the polynomial Education, Institute of Nuclear Science and Technology, Sichuan function for the radial dose function and the anisotropy function with a θ value of 0-90° in 5° intervals and an r of 0.10-0.35 cm in 0.01-cm intervals. The radial and axial dose profiles and away-along quality assurance table are also calculated for the unsheathed 32P source. The dose rate D (r0,θo) at the reference point for the unsheathed 32P source is determined to be equal to 1.2660 ± 0 .0006 cGys-1mCi. The radial dose function of the new 32P source shows good agreement with the other 32P source presented in this work with an average difference of 1.78%, Conclusion: Dosimetric data are provided for the new 32P source. These data could be used in treatment-planning systems in clinical practice. Advances in knowledge: Provided a new beta-emitting brachytherapy source that is intended for treatment of liver cancer. A dosimetric study of the unsheathed 32P source for which no published dosimetric data existed was performed. [ABSTRACT FROM AUTHOR]

Objective: There is disagreement regarding the value of the α/β ratio for prostate cancer. Androgen deprivation therapy (ADT) may dominate the effects of dose fractionation on prostate-specific antigen (PSA) response and confound estimates of the α/β ratio. We estimate this ratio from combined data on external beam radiation therapy (EBRT) and brachytherapy (BT)-treated patients, providing a range of doses per fraction, while accounting for the effects of ADT. Methods: We analyse data on 289 patients with local prostate cancer treated with EBRT (2Gy per fraction) or EBRT plus one or two BT boosts of 10Gy each. The timing of ADT was heterogeneous. We develop statistical models to estimate the α/β ratio based upon PSA measurements at 1 year as a surrogate for the surviving fraction of cancer cells as well as combined biochemical+clinical recurrence-free survival (bcRFS), controlling for ADT. Results: For the PSA-based end point, the α/β ratio estimate is 7.7Gy [95% confidence interval (CI): 4.1 to 12.5]. Based on the bcRFS end point, the estimate is 18.0Gy (95% CI: 8.2 to ∞). Conclusion: Our model-based estimates of the α/β ratio, which account for the effects of ADT and other important confounders, are higher than some previous estimates. Advances in knowledge: Although dose inhomogeneities and other limitations may limit the scope of our findings, the data suggest caution regarding the assumptions of the α/β ratio for prostate cancer in some clinical environments. [ABSTRACT FROM AUTHOR]

The article presents a study that compares high-dose-rate (HDR) brachytherapy systems with iridium-192 radiation source, cobalt-60 radioactive source and electronic brachytherapy source (EBS) for endometrial cancer treatment. The study suggests that Xoft-EBS is a suitable HDR source for vaginal applicator treatment as it reduces radiation exposure to organs at risk and increases the vaginal mucosal dose. Details on the results and method of the study are discussed.

Objective: Neoadjuvant " long-course" chemoradiation is considered a standard of care in locally advanced rectal cancer. In addition to prostatectomy, external beam radiotherapy and brachytherapy with or without androgen suppression (AS) are well established in prostate cancer management. A retrospective review of ten cases was completed to explore the feasibility and safety of applying these standards in patients with dual pathology. To our knowledge, this is the largest case series of synchronous rectal and prostate cancers treated with curative intent. Methods: Eligible patients had synchronous histologically proven locally advanced rectal cancer (defined as cT3- 4Nx; cTxNl-2) and non-metastatic prostate cancer (pelvic nodal disease permissible). Curative treatment was delivered to both sites simultaneously. Follow-up was as per institutional guidelines. Acute and late toxicities were reviewed, and a literature search performed. Results: Pelvic external beam radiotherapy (RT) 45-50.4 Gy was delivered concurrent with 5-fluorouracil (5FU). Prostate total dose ranged from 70.0 to 79.2 Gy. No acute toxicities occurred, excluding AS-induced erectile dysfunction. Nine patients proceeded to surgery, and one was managed expectantly. Three relapsed with metastatic colorectal cancer, two with metastatic prostate cancer. Five patients have no evidence of recurrence, and fou r remain alive w ith metastatic disease. With a median follow -u p of 2.2 years (range 1.2-6.3 years), tw o significant late toxicities occurred; G3 pro c titis in a patient receiving palliative bevacizumab and a G3 anastomotic s tricture precluding stoma reversal. Conclusion: Patients proceeding to synchronous radical treatment of both primary sites should receive 45-50.4 Gy pelvic RT with infusional 5FU. Prostate dose escalation should be given with due consideration to the potential impact of prostate cancer on patient survival, as increasing dose may result in significant late morbidity. Review of published series explores the possibility of prostate brachytherapy as an alternative method of boost delivery. Frequent use of bevacizumab in metastatic rectal cancer may compound late rectal morbidity in this cohort. Advances in knowledge: To our knowledge, this is the largest case series of synchronous rectal and prostate cancers treated with curative intent. This article con trib utes to the understanding of how best to approach definitive treatment in these patients. [ABSTRACT FROM AUTHOR]

The article features the incidence of sexual disorder, Erectile Dysfunction (ED) in patients with prostate cancer (PC) and treated with radiotherapy. The paper states that brachytherapy (BT) and external-beam radiotherapy (EBRT) can be offered as curative options for PC. The author finds that ED's incidence is lower in cases of post-radiation than after the surgery for PC. He opines that ED patients should be offered sexual counseling, and be provided with methods of treatments for ED.

Objective: Spacer gel is used to reduce the rectal dose in prostate radiotherapy. It is injected to increase the distance between the prostate and rectum. During the course of external radiotherapy treatment, physiological changes in rectal volume exist. When using polyethylene glycol material, such as DuraSeal® (Covidien, Mansfield, MA), gel resorption also occurs. Together, these factors alter the original dose plan distribution. Methods: External dose planning and calculations were simulated using images acquired from 10 patients who were treated with brachytherapy and gel. The CT series was taken relative to gel injection: pre 1 day, post 1 day, post 1 month and post 2 months. Adaptive planning was compared with a single plan. Results: Adaptive planning shows better results compared with the single plan used in the total treatment course; however, the effect is minor. Conclusion: Gel usage is clearly favourable to rectal DVH. Using adaptive planning with gel improves rectal DVH but is not necessary according to this study. Advances in knowledge: Spacer gel is used in prostate radiotherapy to increase distance between the prostate and the rectum, thus reducing the rectal doses. During the treatment course, gel resorption exists which affects the rectal doses. The usefulness of adaptive planning to compensate this resorption effect has not been studied before. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the dosimetric differences and similarities between treatment plans generated with Axxent-Xoft electronic brachytherapy source (Xoft-EBS), 192lr and 60Co for tandem and ovoids (T&O) applicators. Methods: In this retrospective study, we replanned 10 patients previously treated with 192lr high-dose-rate brachytherapy. Prescription was 7 Gy × 4 fractions to Point A. For each original plan, we created two additional plans with Xoft-EBS and 6°Co. The dose to each organ at risk (OAR) was evaluated in terms of l/35% and V50%, the percentage volume receiving 35% and 50% of the prescription dose, respectively, and D2cc, highest dose to a 2 cm3 volume of an OAR. Results: There was no difference between plans generated by 192lr and 60Co, but the plans generated using Xoft-EBS showed a reduction of up to 50% in V3S%, VSo% and D2cc. The volumes of the 200% and 150% isodose lines, however, were 74% and 34% greater than the comparable volumes generated with the 192lr source. Point B dose was on average only 16% of the Point A dose for plans generated with Xoft-EBS compared with 30% for plans generated with 192lr or 60Co. Conclusion: The Xoft-EBS can potentially replace either 192lr or 60Co in T&O treatments. Xoft-EBS offers either better sparing of the OARs compared with 192lr or 60Co or at least similar sparing. Xoft-EBS-generated plans had higher doses within the target volume than 192lr- or 60Co generated ones. Advances in knowledge: This work presents newer knowledge in dosimetric comparison between Xoft-EBS, 192lr or 60Co sources for T&O implants. [ABSTRACT FROM AUTHOR]

In the past decade, electronic brachytherapy (EB) has emerged as an attractive modality for the treatment of skin lesions and intraoperative partial breast irradiation, as well as finding wider applications in intracavitary and interstitial sites. These miniature X-ray sources, which operate at low kilovoltage energies (<100 kV), have reduced shielding requirements and inherent portability, therefore can be used outside the traditional realms of the radiotherapy department. However, steep dose gradients and increased sensitivity to inhomogeneities challenge accurate dosimetry. Secondly, ease of use does not mitigate the need for close involvement by medical physics experts and consultant oncologists. Finally, further studies are needed to relate the more heterogeneous dose distributions to clinical outcomes. With these provisos, the practical convenience of EB strongly suggests that it will become an established option for selected patients, not only in radiotherapy departments but also in a range of operating theatres and clinics around the world. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the incidence, size and predisposing factors for air pockets around the vaginal cylinder and their dosimetric effect on the vaginal mucosa. Methods: We investigated 174 patients with endometrial carcinoma treated with external radiotherapy (RT) and brachytherapy (BRT) (101 patients 58%) or BRT alone (73 patients, 42%). The quantity, volume and dosimetric impact of the air pockets surrounding the vaginal cylinder were quantified. The proportions of patients with or without air pockets during application were stratified according to menopausal status, treatment modality and interval between surgery and RT. Results: Air pockets around the vaginal cylinder were seen in 75 patients (43%), while 99 patients (57%) had no air pockets. Only 11 patients (6.3%) received less than the prescribed dose (average 93.9% of prescribed dose; range. 79.0-99.2%). Air pockets were significantly fewer in pre-menopausal patients or in patients treated with the combination of external RT and BRT than in postmenopausal patients or patients treated with BRT alone. A significant correlation existed between the mucosal displacement of the air gap and the ratio of the measured dose at the surface of the air gap and prescribed dose (Pearson r = -0.775; ρ < 0.001). Conclusion: Air pockets were still a frequent problem during vaginal vault BRT. especially in post-menopausal patients or in patients treated with BRT alone, which may potentially cause dose reductions at the vaginal mucosa. Advances in knowledge: Air pockets around the vaginal cylinder remain a significant problem, which may potentially cause dose reduction in the target volume. [ABSTRACT FROM AUTHOR]

Dosimetric audit is required for the improvement of patient safety in radiotherapy and to aid optimization of treatment. The reassurance that treatment is being delivered in line with accepted standards, that delivered doses are as prescribed and that quality improvement is enabled is as essential for brachytherapy as it is for the more commonly audited external beam radiotherapy. Dose measurement in brachytherapy is challenging owing to steep dose gradients and small scales, especially in the context of an audit. Several different approaches have been taken for audit measurement to date: thimble and well-type ionization chambers, thermoluminescent detectors, optically stimulated luminescence detectors, radiochromic film and alanine. In this work, we review all of the dosimetric brachytherapy audits that have been conducted in recent years, look at current audits in progress and propose required directions for brachytherapy dosimetric audit in the future. The concern over accurate source strength measurement may be essentially resolved with modern equipment and calibration methods, but brachytherapy is a rapidly developing field and dosimetric audit must keep pace. [ABSTRACT FROM AUTHOR]

Following literature contributions delineating the deficiencies introduced by the approximations of conventional brachytherapy dosimetry, different model-based dosimetry algorithms have been incorporated into commercial systems for 192Ir brachytherapy treatment planning. The calculation settings of these algorithms are pre-configured according to criteria established by their developers for optimizing computation speed vs accuracy. Their clinical use is hence straightforward A basic understanding of these algorithms and their limitations is essential, however, for commissioning; detecting differences from conventional algorithms; explaining their origin; assessing their impact; and maintaining global uniformity of clinical practice. [ABSTRACT FROM AUTHOR]

This article reviews recent developments in primary standards for the calibration of brachytherapy sources, with an emphasis on the currently most common photon-emitting radionuclides. The introduction discusses the need for reference dosimetry in brachytherapy in general. The following section focuses on the three main quantities, i.e. reference air kerma rate, air kerma strength and absorbed dose rate to water, which are currently used for the specification of brachytherapy photon sources and which can be realized with primary standards from first principles. An overview of different air kerma and absorbed dose standards, which have been independently developed by various national metrology institutes over the past two decades, is given in the next two sections. Other dosimetry techniques for brachytherapy will also be discussed. The review closes with an outlook on a possible transition from air kerma to absorbed dose to water-based calibrations for brachytherapy sources in the future. [ABSTRACT FROM AUTHOR]

Objective: To consider the implications of the use of biphasic rather than monophasic repair in calculations of biologically-equivalent doses for pulsed-dose-rate brachytherapy of cervix carcinoma. Methods: Calculations are presented of pulsed-dose-rate (PDR) doses equivalent to former low-dose-rate (LDR) doses, using biphasic vs monophasic repair kinetics, both for cervical carcinoma and for the organ at risk (OAR), namely the rectum. The linear-quadratic modelling calculations included effects due to varying the dose per PDR cycle, the dose reduction factor for the OAR compared with Point A, the repair kinetics and the source strength. Results: When using the recommended 1 Gy per hourly PDR cycle, different LDR-equivalent PDR rectal doses were calculated depending on the choice of monophasic or biphasic repair kinetics pertaining to the rodent central nervous and skin systems. These differences virtually disappeared when the dose per hourly cycle was in- creased to 1.7 Gy. This made the LDR-equivalent PDR doses more robust and independent of the choice of repair kinetics and α/β ratios as a consequence of the described concept of extended equivalence. Conclusion: The use of biphasic and monophasic repair kinetics for optimised modelling of the effects on the OAR in PDR brachytherapy suggests that an optimised PDR protocol with the dose per hourly cycle nearest to 1.7 Gy could be used. Hence, the durations of the new PDR treatments would be similar to those of the former LDR treatments and not longer as currently prescribed. Advances in knowledge: Modelling calculations indicate that equivalent PDR protocols can be developed which are less dependent on the different α/β ratios and monophasic/biphasic kinetics usually attributed to normal and tumour tissues for treatment of cervical carcinoma. [ABSTRACT FROM AUTHOR]

Objective: To assess the technical feasibility, safety and clinical outcome of CT-guided high-dose-rate brachy- therapy (CT-HDRBT) for achieving local tumour control (LTC) in isolated lymph node metastases. Methods: From January 2008 to December 2011, 10 patients (six males and four females) with isolated nodal metastases were treated with CT-HDRBT. Five lymph node metastases were para-aortic, three were at the liver hilum, one at the coeliac trunk and one was a left iliac nodal metastasis. The mean lesion diameter was 36.5mm (range 12.0-67.0mm). Patients were followed up by either contrast-enhanced CT or MRI 6 weeks and then every 3 months after the end of treatment. The primary end point was LTC. Secondary end points included primary technical effectiveness rate, adverse events and progression-free survival. Results: The first follow-up examination after 6 weeks revealed complete coverage of all nodal metastases treated. There was no peri-interventional mortality or major complications. The mean follow-up period was 13.2 months (range 4-20 months). 2 out of 10 patients (20%) showed local tumour progression 9 and 10 months after ablation. 5 out of 10 patients (50%) showed systemic tumour progression. The mean progression- free interval was 9.2 months (range 2-20 months). Conclusion: CT-HDRBT is a safe and effective technique for minimally invasive ablation of nodal metastases. Advances in knowledge: CT-HDRBT of lymph node metastases is feasible and safe. CT-HDRBT might be a viable therapeutic alternative to obtain LTC in selected patients with isolated lymph node metastases. [ABSTRACT FROM AUTHOR]

Quantifying organ dose to healthy organs during radiotherapy is essential to estimate the radiation risk. Dose factors are generated by simulating radiation transport through an anthropomorphic mathematical phantom representing a reference Indian adult using the Monte Carlo method. The mean organ dose factors (in mGy min−1 GBq−1) are obtained considering the microselectron 192Ir source and BEBIG 60Co sources in the uterus of a reference Indian adult female phantom. The present study provides the factors for mean absorbed dose to organs applicable to the Indian female patient population undergoing brachytherapy treatment of uterus cancer. This study also includes a comparison of the dimension of organs in the phantom model with measured values of organs in the various investigated patients. [ABSTRACT FROM PUBLISHER]

Photoluminescence glass dosemeters (PLDs) and thermoluminescence dosemeters (TLDs) are commonly used as a personal monitoring dosemeter. PLDs and TLDs were used for surface dose monitoring of medical staff involved in 125I brachytherapy for prostate cancer because these dosemeters have a wide dose–response linearity and high sensitivity for low photon energy. Surface doses measured with PLDs agreed with those with TLDs within ∼20 % except for a few cases. Surface doses at a surgeon's left hand and arm were higher than those at the other measuring points. A surgeon received a maximum dose of 650 μGy at the back of left hand. Surface doses to an assistant were <100 μGy. Surface doses to a nurse, a radiologist, an anaesthesiologist and a radiological technologist were <10 μGy. The occupational exposure to a surgeon could be reduced by the adjustment of fluoroscopic parameters and the use of lead gloves. [ABSTRACT FROM PUBLISHER]

Background. Basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) are among the most common cancers in humans. Various therapies are currently being used to treat these tumours including surgery, topical treatments and radiotherapy. We describe a new treatment for BCC and SCC. This consists of superficial radiotherapy, using synthetic resin containing a radioactive β-emitting isotope. The resin is applied to the lesion to perform a selective β-irradiation brachytherapy treatment. Methods. In total, 53 patients with histologically confirmed diagnosis of BCC and of SCC were enrolled for the treatment. Results. In all treated cases, an apparent clinical remission occurred in approximately 3 months, and complete healing was obtained in 100% of the treated patients; in 82% of the cases, this occurred after a single application. No disfiguring scars or any side-effects were seen. After a follow-up of 20–72 months (mean 51 months), no clinical relapses were observed in the treated patients. Histological examination confirmed complete tumour regression. Conclusion. The results indicated that brachytherapy is an effective treatment for BCC and SCC. [ABSTRACT FROM AUTHOR]

Abstract: Objective: Despite the success of antiproliferative therapies, restenosis remains a common problem after percutaneous transluminal coronary angioplasty (PTCA). Longer-term clinical results of brachytherapy (intracoronary radiation), the lack of long-term clinical results after implantation of drug eluting stents, and the occurrence of late thrombosis after both procedures leave room for skepticism. Neointimal proliferation is not substantially inhibited at late time points after brachytherapy, and late lumen loss with a “catch-up” proliferation can occur. We hypothesized that the transcription factors nuclear factor-{kappa}B (NF-κB) and activator protein-1 (AP-1) are involved in these processes. We addressed the role of these mediators in a porcine model of coronary restenosis. Methods: Thirty-nine pigs underwent PTCA in two major coronary arteries. One of the two balloon-injured arteries was randomly assigned to receive immediate 20 Gy beta-irradiation (Brachy group) using a noncentered source train (90Sr/Y Beta-Cath, Novoste). Animals were sacrificed after 1 day, 14 days, or 28 days. Proliferating cells were labeled prior to euthanasia. Results: At late time points, lumen area was significantly smaller and the inflammatory response was more pronounced in the Brachy group than in the PTCA group. These findings coincided with sustained activation of MMP-9 and transcription factors like NF-κB and AP-1. Initially, cell proliferation was reduced in the Brachy group; however, at late time points, differences between the two treatment groups were no longer significant. Conclusions: Brachytherapy initially inhibits cell proliferation; however, cellular and molecular inflammatory processes (e.g. activation of NF−κB) are enhanced within the arterial wall. This proinflammatory side effect may be responsible for the observed delayed proliferation and the resulting lumen loss. [Copyright &y& Elsevier]

In March 2004, the American Association of Physicists in Medicine (AAPM) published an update to the AAPM Task Group No. 43 Report (TG-43) which was initially published in 1995. This update was pursued primarily due to the marked increase in permanent implantation of low-energy photon-emitting brachytherapy sources in the United States over the past decade, and clinical rationale for the need of accurate dosimetry in the implementation of interstitial brachytherapy. Additionally, there were substantial improvements in the brachytherapy dosimetry formalism, accuracy of related parameters and methods for determining these parameters. With salient background, these improvements are discussed in the context of radiation dosimetry. As an example, the impact of this update on the administered dose is assessed for the model 200 103Pd brachytherapy source. [ABSTRACT FROM AUTHOR]

The linearity of dose response of chemical vapour deposition (CVD) diamonds grown at the Institute for Materials Research at Limburg University, Belgium, was investigated over a dose range relevant for radiotherapy. The following CVD diamonds were investigated: (1) a batch of square 3 × 3 mm² detectors cut from a CVD wafer and (2) an as-grown CVD wafer of 6 cm diameter. A total of 20 CVD square detectors were irradiated with 137Cs gamma rays over the dose range from 200 mGy to 25 Gy. The CVD wafer, used as a large-area thermoluminescent (TL) detector, was exposed to a 226Ra needle. Very few square detectors showed linearity over a limited dose range, followed by saturation of the TL signal. The dose range of linearity was found to be strongly affected by the thermal annealing procedure of the detector. Owing to its high sensitivity and homogeneity of response, the large CVD diamond wafer was found to be very suitable as a large-area detector for 2-D dose mapping of the 226Ra brachytherapy source, possibly for Quality Assurance purposes. [ABSTRACT FROM AUTHOR]

The present work proposes a new mathematical eye model for ophthalmic brachytherapy dosimetry. This new model includes detailed description of internal structures that were not treated in previous works, allowing dose determination in different regions of the eye for a more adequate clinical analysis. Dose calculations were determined with the MCNP-4C Monte Carlo particle transport code running n parallel environment using PVM. The Amersham CKA4 ophthalmic applicator has been chosen and the depth dose distribution has been determined and compared to those provide by the manufacturer. The results have shown excellent agreement. Besides, absorbed dose values due to both 125I seeds and 60Co plaques were obtained for each one of the different structures which compose the eye model and can give relevant information in eventual clinical analyses. [ABSTRACT FROM AUTHOR]

Prostate cancer is receiving ever more publicity with the result that more men are having their prostate specific antigen checked and a greater proportion of men are diagnosed with potentially curable localised disease. Advances in the therapeutic modalities including radical surgery, external beam radiotherapy, and brachytherapy have reduced the incidence of side effects and now offer patients a choice of treatments depending on their tumour characteristics, age, and co-morbidity. A significant proportion of men do not need intervention and may be safely kept under a "watch and wait" policy. The use of genetic markers may in the future distinguish between patients most likely to benefit from radical therapy and those in who either palliation or observation is more appropriate. This review examines the potentially curative options, as well as expectant management, outlining the pros and cons of each. The use of adjuvant and neoadjuvant therapy is also discussed. [ABSTRACT FROM AUTHOR]

Image-guided radiotherapy (IGRT) is a recommended advanced radiation technique that is associated with fewer acute and chronic toxicities. However, one Phase III trial showed worse overall survival in the IGRT arm. The purpose of this observational study is to evaluate the impact of IGRT on overall survival. We used the Taiwan Cancer Registry Database to enroll cT1-4N0M0 prostate cancer patients who received definitive radiotherapy between 2011 and 2015. We used inverse probability treatment weighting (IPW) to construct balanced IGRT and non-IGRT groups. We compared the overall survival of those in the IGRT and non-IGRT groups. Supplementary analyses (SA) were performed with alternative covariates in propensity score (PS) models and PS approaches. The incidence rates of prostate cancer mortality (IPCM), other cancer mortality (IOCM), and cardiovascular mortality (ICVM) were also evaluated. There were 360 patients in the IGRT arm and 476 patients in the non-IGRT arm. The median follow-up time was 50 months. The 5-year overall survival was 88% in the IGRT arm and 86% in the non-IGRT arm (adjusted hazard ratio [HR] of death = 0.93; 95% CI, 0.61–1.45; p = 0.77). The SA also showed no significant differences in the overall survival between those in the IGRT and non-IGRT arms. Both groups did not significantly differ in terms of IPCM, IOCM, and ICVM. The overall survival of localized prostate cancer patients who underwent IGRT was not inferior to those who did not. We demonstrated that the overall survival for prostate cancer patients with IGRT was not worse than those who did not undergo IGRT; this important outcome comparison has not been previously examined in the general population. [ABSTRACT FROM AUTHOR]

We determined the sensitivity and specificity of multiparametric magnetic resonance imaging (MP-MRI) in detection of locally recurrent prostate cancer and extra prostatic extension in the post-radical radiotherapy setting. Histopathological reference standard was whole-mount prostatectomy specimens. We also assessed for any added value of the dynamic contrast enhancement (DCE) sequence in detection and staging of local recurrence. This was a single centre retrospective study. Participants were selected from a database of males treated with salvage prostatectomy for locally recurrent prostate cancer following radiotherapy. All underwent pre-operative prostate-specific antigen assay, positron emission tomography CT, MP-MRI and transperineal template prostate mapping biopsy prior to salvage prostatectomy. MP-MRI performance was assessed using both Prostate Imaging-Reporting and Data System v. 2 and a modified scoring system for the post-treatment setting. 24 patients were enrolled. Using Prostate Imaging-Reporting and Data System v. 2, sensitivity, specificity, positive predictive value and negative predictive value was 64%, 94%, 98% and 36%. MP-MRI under staged recurrent cancer in 63%. A modified scoring system in which DCE was used as a co-dominant sequence resulted in improved diagnostic sensitivity (61%–76%) following subgroup analysis. Our results show MP-MRI has moderate sensitivity (64%) and high specificity (94%) in detecting radio-recurrent intraprostatic disease, though disease tends to be under quantified and under staged. Greater emphasis on dynamic contrast images in overall scoring can improve diagnostic sensitivity. MP-MRI tends to under quantify and under stage radio-recurrent prostate cancer. DCE has a potentially augmented role in detecting recurrent tumour compared with the de novo setting. This has relevance in the event of any future modified MP-MRI scoring system for the irradiated gland. [ABSTRACT FROM AUTHOR]

To compare the efficacy and tolerance of 7-days-a-week accelerated postoperative radiotherapy (p-CAIR) vs postoperative radio-chemotherapy (p-RTCT) Between September 2007 and October 2013, 111 patients were enrolled and randomly assigned to receive 63 Gy in 1.8 Gy fractions 7-days-a-week (n = 57, p-CAIR) or 63 Gy in 1.8 Gy fractions 5-days-a-week with concurrent cisplatin 80–100 mg per square meter of body-surface area on days 1, 22 and 43 of the radiotherapy course (p-RTCT). It represents approximately 40% of the intended trial size, that was closed prematurely due to slowing accrual. Only high-risk patients with squamous cell cancer of the oropharynx/oral cavity, considered fit for concurrent treatment were enrolled. The rate of locoregional control (LRC) did not differ significantly between treatment arms (p = 0.18, HR = 0.56), 5 year LRC tended, however, to favour p-RTCT (81%) vs p-CAIR (62%). There was no difference in overall survival between treatment arms (p = 0.90, HR = 1.03). The incidence and severity of acute mucosal reactions and late reactions did not differ significantly between treatment arms. Haematological toxicity of p-RTCT was, however, considerably increased compared to p-CAIR Concurrent postoperative RTCT tended to improve locoregional control rate as compared to p-CAIR. This, however, did not transferred into improved overall survival. Postoperative RTCT was associated with a substantial increase in haematological toxicity that negatively affected treatment compliance in this arm. To our knowledge, this is the first trial that compares accelerated radiotherapy and radio-chemotherapy in postoperative treatment for oralcavity/oropharyngeal cancer [ABSTRACT FROM AUTHOR]

The isotope bone scan (IBS) is the gold-standard imaging modality for detecting skeletal metastases as part of prostate cancer staging. However, its clinical utility for assessing skeletal metastatic burden is limited due to the need for subjective interpretation. We designed and tested a novel custom software tool, the Metastatic Bone Scan Tool (MetsBST), aimed at improving interpretation of IBSs, and compared its performance with that of an established software programme. We used IBS images from 62 patients diagnosed with prostate cancer and suspected bone metastases to design and implement MetsBST in MATLAB by defining thresholds used to identify the texture and size of metastatic bone lesions. The results of MetsBST were compared with those of the commercially available automated Bone Scan Index (aBSI) with regression analysis. There was strong agreement between the MetsBST and aBSI results (R2 = 0.9189). In a subregional analysis, MetsBST quantified the extent of metastatic disease in multiple bone sites in patients receiving multimodality therapy (radium-223 and external beam radiotherapy) to illustrate the differences in bone metastatic response to different treatments. The results of MetsBST and the commercial software aBSI were highly consistent. MetsBST introduces novel clinical utility by its ability to differentiate between the responses of different bone metastases to multimodality therapies. MetsBST reduces the variability in assessment of tumour burden caused by subjective interpretation. Therefore, it is a useful aid to physicians reporting nuclear medicine scans, and may improve decision-making in the treatment of metastatic prostate cancer. [ABSTRACT FROM AUTHOR]

Glioblastoma multiforme (GBM) is a highly infiltrative primary brain tumour with an aggressive clinical course. Diffusion tensor imaging (DT-MRI or DTI) is a recently developed technique capable of visualising subclinical tumour spread into adjacent brain tissue. Tensor decomposition through p and q maps can be used for planning of treatment. Our objective was to develop a tool to automate the segmentation of DTI decomposed p and q maps in GBM patients in order to inform construction of radiotherapy target volumes. Chan-Vese level set model is applied to segment the p map using the q map as its initial starting point. The reason of choosing this model is because of the robustness of this model on either conventional MRI or only DTI. The method was applied on a data set consisting of 50 patients having their gross tumour volume delineated on their q map and Chan-Vese level set model uses these superimposed masks to incorporate the infiltrative edges. The expansion of tumour boundary from q map to p map is clearly visible in all cases and the Dice coefficient (DC) showed a mean similarity of 74% across all 50 patients between the manually segmented ground truth p map and the level set automatic segmentation. Automated segmentation of the tumour infiltration boundary using DTI and tensor decomposition is possible using Chan-Vese level set methods to expand q map to p map. We have provided initial validation of this technique against manual contours performed by experienced clinicians. This novel automated technique to generate p maps has the potential to individualise radiation treatment volumes and act as a decision support tool for the treating oncologist. [ABSTRACT FROM AUTHOR]

Patients with locally advanced non-small cell lung cancer (NSCLC) were included in a prospective trial for radiotherapy in deep inspiration breath hold (DIBH). We evaluated DIBH compliance and target position reproducibility. Voluntary, visually guided DIBHs were performed with optical tracking. Patients underwent three consecutive DIBH CT scans for radiotherapy planning. We evaluated the intrafractional uncertainties in the position of the peripheral tumour, lymph nodes and differential motion between them, enabling PTV margins calculation. Patients who underwent all DIBH imaging and had tumour position reproducibility <8 mm were up-front DIBH compliant. Patients who performed DIBHs throughout the treatment course were overall DIBH compliant. Clinical parameters and DIBH-related uncertainties were validated against our earlier pilot study. 69 of 88 included patients received definitive radiotherapy. 60/69 patients (87%) were up-front DIBH compliant. DIBH plan was not superior in seven patients and three lost DIBH ability during the treatment, leaving 50/69 patients (72%) overall DIBH compliant. The systematic and random errors between consecutive DIBHs were small but differed from the pilot study findings. This led to slightly different PTV margins between the two studies. DIBH compliance and reproducibility was high. Still, this validation study highlighted the necessity of designing PTV margins in larger, representative patient cohorts. We demonstrated high DIBH compliance in locally advanced NSCLC patients. DIBH does not eliminate but mitigates the target position uncertainty, which needs to be accounted for in treatment margins. Margin design should be based on data from larger representative patient groups. [ABSTRACT FROM AUTHOR]

One approach to reduce treatment-related morbidity for human papilloma virus (HPV)-associated tonsil cancer is omitting radiotherapy to the contralateral neck. Pathologic risk factors for early contralateral neck disease, however, are poorly understood. We report on the risk contralateral neck failures from the time of pre-operative diagnostic imaging to time of planning for adjuvant radiation in a single institution series of HPV-associated tonsillar cancer patients undergoing surgery followed by radiotherapy (RT). Retrospective analysis of 123 patients with T1–T3 HPV-positive tonsillar squamous cell carcinoma treated between 2010 and 2016 with transoral robotic surgery and selective ipsilateral neck dissection followed by adjuvant RT. Contralateral neck recurrence was classified as the detection of a pathologic node in the contralateral neck prior to initiation of adjuvant RT. Seven patients (5.7%) developed contralateral neck disease/failure between the time of pre-operative diagnostic neck imaging and time of planning of adjuvant radiation. Increased ratio of positive/resected nodes [odds ratio (OR) 1.073, p = 0.005] was significantly associated with increased risk of contralateral neck recurrence, with a trend found for close/positive margins (OR 5.355, p = 0.06), tumor size (OR 2.046, p = 0.09), and total number of nodes positive (OR 1.179, p = 0.062). Patients who develop very early contralateral neck disease, between completion of ipsilateral neck dissection and the initiation of radiotherapy, have a higher ratio of positive nodes to total nodes resected in the ipsilateral neck. These findings suggest that proper selection of patients for omission of treatment of the contralateral, node-negative neck should be made with this in mind, with future studies needed to document the impact on toxicity and disease outcomes from such an approach. Pathologic risk factors in the dissected, ipsilateral neck in patients with tonsil cancer may inform the risk of contralateral neck failure. Patient selection for future, prospective efforts to examine sparing of the contralateral neck need to be based with these risk factors in mind. [ABSTRACT FROM AUTHOR]

To evaluate the outcomes of stereotactic radiotherapy (SBRT) in the treatment of inoperable hepatocellular carcinomas (HCC) that are unsuitable for, or refractory to other liver-directed therapies. Between March 2015 and June 2018, patients with primary HCCs refractory to or unsuitable for treatment with other liver-directed therapies were treated with SBRT. Patients of Child status A5-B7 and with normal liver reserve ≥ 700 cc were preferred. Local control (LC), overall survival (OS), progression free survival (PFS) and effect of prognostic factors were analysed. 21 patients with inoperable HCCs were treated. The median tumour diameter was 9.6 cm (5-21) and median tumour volume was 350 cc (32.9 – 2541). The median SBRT dose prescription was 42 Gy/6 fractions (25 – 54 Gy/6#). The 1- and 2-year LC rate was 88 and 43 % respectively. Overall rate of > grade III toxicity was 14 %. Patients with Child A5 liver function had a better median OS than A6 and B7 patients [21 vs 11 vs 8 months]. Also, tumours with GTV < 350 cc volumes had a better OS compared to GTV of greater than 350 cc [24 months vs 8 months, p value = 0.004]. This study showed that SBRT can be used safely and effectively to treat inoperable HCCs with or without prior loco-regional therapies, resulting in good local control and survival with acceptable toxicity. Use of SBRT in inoperable HCC is safe and effective. [ABSTRACT FROM AUTHOR]

To evaluate high-precision external beam reirradiation (re-EBRT) for local relapse of prostate cancer (PCa) after radiotherapy. This retrospective study included patients with biochemical failure and evidence of isolated local recurrence of PCa after radical/salvage EBRT or brachytherapy that received salvage stereotactic body radiation therapy (SBRT, re-EBRT). Biopsy was not mandatory if all diagnostic elements were univocal (prostate specific antigen evolution, choline-positron emission tomography or magnetic resonance imaging). Salvage SBRT (re-EBRT) was delivered with image-guided radiation therapy (RapidArc®, VERO® and CyberKnife®). Data of 64 patients were included, median age at salvage SBRT was 73.2 years, median pre-salvage SBRT prostate specific antigen was 3.89 ng ml−1. Median total dose was 30 Gy in five fractions, biologically effective dose (BED) of 150 Gy. One acute G3 genitourinary event and one late G3 genitourinary event were observed. No G ≥ 3 bowel toxicity was registered. At the median follow-up of 26.1 months, tumor progression was observed in 41 patients (64%). 18 patients (28%) experienced local relapse. 2-year local control, biochemical and clinical relapse free survival rates were 75, 40 and 53%, respectively. With BED ≥130 Gy 1-year biochemical and clinical progression-free survival rate were 85 and 90%, respectively. Salvage SBRT (re-EBRT) for isolated local PCa recurrence is a safe, feasible and noninvasive salvage treatment. Further investigation is warranted to define the optimal patient selection, dose and volume parameters. Salvage SBRT reirradiation for the locally recurrent PCa offer a satisfactory tumor control and excellent toxicity profile, if BED ≥130 Gy is administered. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the editor discusses various reports within the issue on topics including the calibration of brachytherapy sources, algorithms for brachytherapy treatment and best-practice brachytherapy planning.