End-to-end delivery quality assurance of computed tomography–based high-dose-rate brachytherapy using a gel dosimeter

PurposeThe purpose of this study was to develop a novel quality assurance (QA) program to check the entire treatment chain of image-guided brachytherapy with dose distribution evaluation in a single setup and irradiation using a gel dosimeter.Methods and MaterialsA polymer gel was used, and the readout was performed by magnetic resonance scanning. A CT-based treatment plan was generated using the Oncentra planning system (Elekta, Sweden), and irradiation was performed three times using an afterloading device with an Ir-192 source. The dose-response curve of the gel was created using 6-MV X-ray, which is independent of the source beams. Planar gamma images on a coronal plane along the source transport axis were calculated using the measured dose as a reference, and the calculated doses were used in several error simulations (no error; 2.0 or 2.5 mm systematic and random source dwell mispositioning; and dose error of 2%, 5%, 10%, and 20%).ResultsThe dose-R₂ (spin-spin relaxation rate) conversion table revealed that the uncertainty and dose resolution of 6-MV X-ray were better than those of Ir-192 and also constant between the three measurements. With the 3%/1 mm criteria, there were statistically significant differences between each pair of settings except dose error of 2% and 5%.ConclusionThis work depicts a simple and efficient end-to-end test that can provide a clinically useful tool for QA of image-guided brachytherapy. In this QA program, air kerma strength and dwell position setting could also be verified. This test can also distinguish between different types of error.     

3T multiparametric MRI–guided high-dose-rate combined intracavitary and interstitial adaptive brachytherapy for the treatment of cervical cancer with a novel split-ring applicator

PurposeTo evaluate the role of 3T-MRI–guided adaptive high-dose-rate (HDR) combined intracavitary and interstitial brachytherapy for cervical cancer using a novel intracavitary split-ring (ICSR) applicator adapter.Methods and MaterialsWe retrospectively reviewed all HDR brachytherapy cases from 2013 to 2015 using an ICSR applicator. Initial optimization was performed using 3T multiparametric MRI (mpMRI) series with an applicator in place. The mpMRI series were discretionarily acquired before subsequent fractions for possible target adaptation. When necessary, interstitial needles (ISNs) were inserted through a novel ICSR adapter or freehand. Dosimetric parameters, clinical outcomes, and toxicities were compared between groups.ResultsSeventeen patients were included, with a mean followup of 32 months. An mpMRI series preceded each initial fraction and 52.9% of patients underwent ≥1 additional pretreatment mpMRI. Among these subsequent fractions, the high-risk clinical target volume was reduced in 80% vs. 41% without pretreatment mpMRI. Five patients had ISN placement (seven insertions) to improve extracervical target coverage. Mean D₉₀ (Gy) per fraction to the high-risk clinical target volume and intermediate-risk clinical target volume with and without an ISN were 7.51 ± 1.07 vs. 6.14 ± 0.52 (p = 0.028) and 6.35 ± 0.75 vs. 5.21 ± 0.49 (p = 0.007), respectively. Mean fractional D_2cc (Gy) for organs at risk was comparable. No Grades 3–4 toxicity was reported. Disease-free survival and local control for the ICSR-ISN and ICSR-alone groups were 29.8 months/80.0% and 31.2 months/83.3%, respectively.ConclusionsThe mpMRI acquisition with ICSR applicator in place immediately before HDR brachytherapy for cervical cancer guided successful adaptive treatment optimization and delivery. Our initial experience with a novel interstitial adapter for the split-ring applicator demonstrated excellent target coverage without compromising organs at risk, resulting in good local control and disease-free survival.     

A machine-learning–based prediction model of fistula formation after interstitial brachytherapy for locally advanced gynecological malignancies

PurposeExternal beam radiotherapy combined with interstitial brachytherapy is commonly used to treat patients with bulky, advanced gynecologic cancer. However, the high radiation dose needed to control the tumor may result in fistula development. There is a clinical need to identify patients at high risk for fistula formation such that treatment may be managed to prevent this toxic side effect. This work aims to develop a fistula prediction model framework using machine learning based on patient, tumor, and treatment features.Methods and MaterialsThis retrospective study included 35 patients treated at our institution using interstitial brachytherapy for various gynecological malignancies. Five patients developed rectovaginal fistula and two developed both rectovaginal and vesicovaginal fistula. For each patient, 31 clinical features of multiple data types were collected to develop a fistula prediction framework. A nonlinear support vector machine was used to build the prediction model. Sequential backward feature selection and sequential floating backward feature selection methods were used to determine optimal feature sets. To overcome data imbalance issues, the synthetic minority oversampling technique was used to generate synthetic fistula cases for model training.ResultsSeven mixed data features were selected by both sequential backward selection and sequential floating backward selection methods. Our prediction model using these features achieved a high prediction accuracy, that is, 0.904 area under the curve, 97.1% sensitivity, and 88.5% specificity.ConclusionsA machine-learning–based prediction model of fistula formation has been developed for patients with advanced gynecological malignancies treated using interstitial brachytherapy. This model may be clinically impactful pending refinement and validation in a larger series.     

Management of Bartholin’s gland carcinoma using high-dose-rate interstitial brachytherapy boost

PurposeTo describe the patterns of use, clinical outcomes, and dose–volume histogram parameters of high-dose-rate interstitial brachytherapy (HDR-ISBT) in the management of Bartholin’s gland cancer.Methods and MaterialsFive patients with Stage II–III Bartholin‘s gland carcinoma treated with CT-based HDR-ISBT boost were reviewed. Plans were generated using an inverse planning simulated annealing algorithm. Dose–volume histogram parameters were assessed. The total doses of HDR-ISBT and EBRT were converted to total equivalent dose in 2 Gy (EQD₂).ResultsAll 5 patients received HDR-ISBT as a boost (median dose, 30 Gy) after EBRT (median dose, 45 Gy). Three patients received postoperative irradiation for gross residual tumor or positive surgical margins and 2 patients were treated by primary chemoradiotherapy. The median V₁₀₀, D₉₀, and D₁₀₀ for the CTV were 98.3%, 89 Gy₁₀, and 64 Gy₁₀ (EQD₂), respectively. A complete response was observed in all patients. No local recurrence occurred. All patients remain alive and free of disease (median followup, 78 months; range, 8–93). Severe vaginal toxicities were observed, including vaginal necrosis that resolved with hyperbaric oxygen therapy.ConclusionsHDR-ISBT boost after EBRT offers excellent long-term local control in patients with Bartholin’s gland carcinoma. HDR-ISBT should be considered for positive surgical margins or residual tumor after surgery and for locally advanced malignancies treated by primary chemoradiotherapy.     

Rectal morbidity after permanent interstitial brachytherapy for prostate cancer—Impact of Day 1 vs. Day 30 computed tomography–based postimplant dosimetry

PurposeThe aim of the study was to evaluate bowel quality-of-life changes after prostate brachytherapy and the impact of Day 1 vs. Day 30 postimplant dosimetry.Methods and MaterialsIn 61 patients, computed tomography (CT) scans were performed at Days 1 and 30 after ¹²⁵I brachytherapy. The patients have been surveyed prospectively before (time A), 1 month (time B), and >1 year after treatment (time C) using a validated questionnaire (Expanded Prostate Cancer Index Composite). Different parameters were tested for their predictive value on bowel quality-of-life changes (bowel bother score decrease >20 points at time B = BB20; bowel bother score decrease >10 points at time C = BC10), including seed displacements.ResultsMean bowel function/bother score decreased 13/13 points at time B (p < 0.01) and 1/4 points at time C (change not significant). BB20 and BC10 were found in 25% and 20% of patients, respectively. Bowel bother score declines at time B correlated well with declines at time C (r = 0.53; p < 0.01). Prostate volume before implantation and the number of seeds per cubic centimeters were found to be predictive for BB20 and BC10. Smaller rectal wall volumes covered by the 60–100% isodoses at Day 1 were (paradoxically) found to be significantly predictive for BC10. Larger posterior seed displacements between Days 1 and 30 were significantly associated with BB20.ConclusionsQuality-of-life scores have not been found to change significantly >1 year after brachytherapy. Larger rectal wall volumes within higher isodoses at Day 1 or 30 were not found to be predisposing for adverse quality-of-life changes.     

ACR–ABS–ASTRO practice parameter for the performance of radionuclide-based high-dose-rate brachytherapy

purposeThis practice parameter aims to detail the processes, qualifications of personnel, patient selection, equipment, patient and personnel safety, documentation, and quality control and improvement necessary for an HDR brachytherapy program.Methods and MaterialsThis practice parameter was revised collaboratively by the American College of Radiology (ACR), the American Brachytherapy Society (ABS), and the American Society for Radiation Oncology (ASTRO).ResultsBrachytherapy is a radiotherapeutic modality in which radionuclide or electronic sources are used to deliver a radiation dose at a distance of up to a few centimeters by surface, intracavitary, intraluminal, or interstitial application. Brachytherapy alone or combined with external beam radiotherapy plays an important role in the management and treatment of patients with cancer. High-dose-rate (HDR) brachytherapy uses radionuclides, such as iridium-192, at dose rates of ≥12 Gy/hr to a designated target point or volume, and it is an important treatment for a variety of malignant and benign conditions. Its use allows for application of high doses of radiation to defined target volumes with relative sparing of adjacent critical structures.ConclusionsHDR brachytherapy requires detailed attention to personnel, equipment, patient and personnel safety, and continuing staff education. Coordination between the radiation oncologist and treatment planning staff and effective quality assurance procedures are important components of successful HDR brachytherapy programs.     

A prospective trial of real-time magnetic resonance–guided catheter placement in interstitial gynecologic brachytherapy

PurposeTo present outcome and toxicity results of the first real-time intraoperative MRI-guided interstitial approach to gynecologic cancer.Methods and MaterialsFrom February 2004 to December 2006, 25 patients with gynecologic malignancies were enrolled and treated in a prospective clinical trial of real-time MRI-guided interstitial brachytherapy. This was followed by a confirmatory CT imaging scan. Statistical analyses included Kaplan–Meier estimates for overall and relapse-free survival.ResultsMRI visualization of needles during placement permitted accurate placement with no inadvertent insertions. This prevented unnecessary normal-tissue perforation as confirmed by CT simulation. With a mean followup of 3.8 years (range, 2–6.8), 1-, 2-, and 3-year overall survival rates were 80%, 60% and 43%, respectively; corresponding relapse-free survival rates were 79%, 65%, and 59%, respectively. Actuarial acute toxicity rates for any grade were 0% at 0–14 days and 80% (all grade 1) at 14–90 days. Long-term (>180 days) actuarial toxicity rates were 8% gastrointestinal, 4% bladder and 4% vaginal.ConclusionsReal-time MRI guidance during insertion of interstitial needles followed by 3D-planning maximized opportunities for tumor targeting and sparing of normal tissues. Although image guidance requires additional anesthesia time, clinical outcomes indicate potential for a successful reduction in toxicity using 3D image-guided in addition to 3D image-planned brachytherapy.     

Image-guided cervix high-dose-rate brachytherapy treatment planning: Does custom computed tomography planning for each insertion provide better conformal avoidance of organs at risk?

PURPOSE: Intracavitary high-dose-rate (HDR) brachytherapy (BT) for cervical cancer involves multiple applicator insertions. Our study addresses whether customized three-dimensional plans generated for the first insertion (using computed tomography [CT] planning) can be applied to subsequent insertions without significant changes in dose distributions if identical applicators are used. METHODS AND MATERIALS: Twenty-seven patients were treated with external-beam radiotherapy, platinum-based chemotherapy, and HDR BT. Either tandem and ovoids (TO, n=12) or tandem and ring (TR, n=15) applicators were used, based on clinical indications. Postimplant CT scans were acquired and custom plans generated for each insertion. Dose parameters for organs at risk (OARs) from the second insertion were retrospectively compared to those that would have been delivered using the initial plan. RESULTS: Overall, we observed a significant increase (p<0.038) in dose to International Commission on Radiation Units and Measurement points and 2cm(3) volumes of bladder and rectum when a single plan was used. The sigmoid and small bowel exhibited a more variable increase in dose. Applicator-specific results revealed a significant increase (p<0.030) to dose points and volumes for the rectum and bladder for TR applicators. Conversely, dose values from the more flexible TO did not show any significant trend, exhibiting large interpatient variations. CONCLUSIONS: A duplication of planned dwell times and positions from one insertion to the next does not duplicate dose distributions in HDR cervix applications. A single plan used for an entire course of BT can result in significant increases to OAR doses for TR and unpredictable OAR doses for TO applicators. Treatment plans should be tailored for each insertion to reflect current applicator and anatomical geometry.     

Is oncoplastic surgery a contraindication for accelerated partial breast radiation using the interstitial multicatheter brachytherapy method?

PurposeTo evaluate accelerated partial breast irradiation (APBI) in patients after oncoplastic surgery for early breast cancer.Methods and MaterialsA retrospective analysis of 136 breasts of 134 patients, who received breast-conserving oncoplastic surgery for low-risk breast cancer between 2002 and 2010 in the Universities of Vienna and Luebeck followed by adjuvant APBI applying total doses of pulse dose rate of 50.4 Gy or high-dose rate (HDR) of 32 Gy over 4 days. Target volume definition was performed by the use of surgical-free margin data, related to intraoperatively fixed clip positions, pre- and postoperative imaging, and palpation.ResultsAt the time of data acquisition, 131 of 134 patients were alive. The median follow-up time was 39 months (range, 4–106 months). After high-dose rate treatment, 3 of 89 patients showed systemic progress after a mean follow-up of 47 months (range, 19–75 months) and 2 patients had a different quadrant in-breast tumor after 27 and 35 months. One patient died 7 months after treatment of unknown causes. After pulse dose rate treatment, 1 of 45 patients had a local recurrence after 42 months and 1 patient died because of another cause after 13 months. We observed mild fibrosis in 27 breasts, telangiectasia in 6, hyperpigmentation in 14 cases, and keloid formation in 1.ConclusionsThese preliminary results suggest the feasibility of multicatheter APBI after oncoplastic breast-conserving surgery in selected low-risk breast cancer patients; however, special attention to target volume definition is needed. Further prospective investigations with long follow-up are needed to define the real value of the procedure.     

Real-time electromagnetic tracking–based treatment platform for high-dose-rate prostate brachytherapy: Clinical workflows and end-to-end validation

PurposeNew technologies were integrated into a novel treatment platform combining electromagnetically (EM) tracked catheters, a 3D ultrasound (3DUS) imaging device, and a new treatment planning system to provide a real-time prostate high-dose-rate (HDR) brachytherapy treatment system. This work defines workflows for offline CT and online 3DUS planning scenarios and preclinical end-to-end validation of the platform.Methods and MaterialsThe platform is composed of an EM-tracked stylet, a EM-tracked 3DUS probe, and an EM-tracked template guide, all used with the NDI Aurora field generator (NDI, Ontario, Canada). The treatment planning system performs continuous position and angular readings from all three EM sensors into a streamlined environment that allows for (1) contouring; (2) planning; (3) catheter insertion guidance and reconstruction; (4) QA of catheter path and tip position; and (5) exporting to an afterloader. Data were gathered on the times required for the various key steps of the 3DUS-based workflow.ResultsThe complete 3DUS-based workflow on 16-catheter implant phantoms took approximately 15 min. This time is expected to increase for actual patients. Plan generation is fast (7.6 ± 2.5s) and the initial catheter reconstruction with updated dose distribution is obtained at no (time) cost as part of the insertion process. Subsequent catheter reconstruction takes on average 10.5 ± 3.1s per catheter, representing less than 3 min for a 16-catheter implant.ConclusionsThis preclinical study suggests that EM technology could help to significantly streamline real-time US-based high-dose-rate prostate brachytherapy.     

High-dose-rate interstitial brachytherapy for T1–T2-stage penile carcinoma: Short-term results

PurposeInterstitial brachytherapy (IBT) is a preferred treatment option over partial penectomy in selected patients with T1–T2-stage penile carcinoma because of its organ preservation ability. Literature is mostly based on the use of low-dose-rate IBT, and experience with high-dose-rate (HDR) IBT is extremely limited. We studied the role of HDR-IBT alone in patients with T1–T2-stage penile carcinoma.Methods and MaterialsBetween April 2010 and July 2013, 14 patients with T1–T2-stage penile carcinoma were treated with HDR-IBT at our center. Size of the primary lesion ranged from 1.5 to 4.0 cm. A two-to-four–plane free-hand implant was performed using plastic catheters. The prescribed dose of HDR-IBT was 42–51 Gy in 14–17 fractions using twice-a-day fractionation schedule. Patients were followed up regularly for assessment of local control, survival, toxicity, and sexual function.ResultsAt a median followup of 22 months, 2 patients developed recurrent disease at locoregional site. The 3-year overall survival was 83% with penis preservation rate of 93%. All patients developed acute Grade III skin toxicity that healed during 6–8-weeks time. Urethral stenosis and soft tissue necrosis was not seen in any of the patients. A total of 4 patients experienced mild asymptomatic fibrosis in the implanted area. Around 10 patients had satisfactory sexual function status at the last followup visit.ConclusionsAlthough it was a small sample size, our results have demonstrated excellent local control rate and acceptable toxicity with HDR-IBT in patients with T1–T2-stage penile carcinoma.     

Evaluation of bi-objective treatment planning for high-dose-rate prostate brachytherapy—A retrospective observer study

PurposeBi-objective treatment planning for high-dose-rate prostate brachytherapy is a novel treatment planning method with two separate objectives that represent target coverage and organ-at-risk sparing. In this study, we investigated the feasibility and plan quality of this method by means of a retrospective observer study.Methods and MaterialsCurrent planning sessions were recorded to configure a bi-objective optimization model and to assess its applicability to our clinical practice. Optimization software, GOMEA, was then used to automatically generate a large set of plans with different trade-offs in the two objectives for each of 18 patients treated with high-dose-rate prostate brachytherapy. From this set, five plans per patient were selected for comparison to the clinical plan in terms of satisfaction of planning criteria and in a retrospective observer study. Three brachytherapists were asked to evaluate the blinded plans and select the preferred one.ResultsRecordings demonstrated applicability of the bi-objective optimization model to our clinical practice. For 14/18 patients, GOMEA plans satisfied all planning criteria, compared with 4/18 clinical plans. In the observer study, in 53/54 cases, a GOMEA plan was preferred over the clinical plan. When asked for consensus among observers, this ratio was 17/18 patients. Observers highly appreciated the insight gained from comparing multiple plans with different trade-offs simultaneously.ConclusionsThe bi-objective optimization model adapted well to our clinical practice. GOMEA plans were considered equal or superior to the clinical plans. In addition, presenting multiple high-quality plans provided novel insight into patient-specific trade-offs.     

Low-dose computed tomography via spatially adaptive Monte–Carlo reconstruction

Low-dose computed tomography (CT) reduces radiation exposure but decreases signal-to-noise ratio (SNR) and diagnostic capabilities. Noise compensation can improve SNR so low-dose CT can provide valuable information for diagnosis without risking patient radiation exposure. In this study, a novel noise-compensated CT reconstruction method that uses spatially adaptive Monte–Carlo sampling to produce noise-compensated reconstructions is investigated. By adapting to local noise statistics, a non-parametric estimation of the noise-free image is computed that successfully handles non-stationary noise found in low-dose CT images. Using phantom and real low-dose CT images, effective noise suppression is shown to be accomplished while maintaining structures and details.     

Reporting of dose–volume specifications for “Martinez Universal Perineal Interstitial Template–based interstitial high-dose-rate brachytherapy for gynecological cancers” according to International Commission on Radiation Units and Measurements 58 with early clinical outcomes

PurposeThe study is an audit of reporting dose and volume specifications as per the ICRU 58 for MUPIT-based interstitial brachytherapy in gynecological cancers. Correlation between total reference air kerma (TRAK) and isodose surface was also evaluated to understand the intensity of treatment in interstitial brachytherapy.Methods and MaterialsForty-two patients underwent HDR MUPIT-based interstitial brachytherapy 20 Gy in five fractions after EBRT during 2017–2019. Treated volume, high and low-dose regions, mean central dose, Dose Homogeneity Index (DHI), organ at risk doses, and TRAK values were computed.ResultsHigh-dose regions V150 mean was 12.4 cc and V200 was 4.58 cc; and low-dose region was 75.92 cc. The mean treated volume was 59.8 cc. The mean central dose was 3.7 Gy. DHI was 79%. The mean D2cm³ bladder and rectum were 2.9 Gy and 2.8 Gy. The mean TRAK was 0.16 cGy per fraction per hour at 1 m. TRAK values showed significant correlation with various isodose volumes (TRAK and V100: r = 0.943 p < 0.0005; and TRAK and V50: r = 0.953; p < 0.0005). A positive correlation was observed between TRAK and the number of needles (r = 0.746; p < 0.0005). At a median followup of 16 months, 4 of 42 patients (9.5%) had local recurrences.ConclusionsOur study shows compliance with ICRU 58 recommendations along with certain deviations. Local recurrence rate is acceptable. TRAK shows correlation with surface isodose in MUPIT-based brachytherapy and should to be evaluated in future studies.     

ACR–ABS–ACNM–ASTRO–SIR–SNMMI practice parameter for selective internal radiation therapy or radioembolization for treatment of liver malignancies

PurposeThe American College of Radiology (ACR), American Brachytherapy Society (ABS), American College of Nuclear Medicine (ACNM), American Society for Radiation Oncology (ASTRO), Society of Interventional Radiology (SIR), and Society of Nuclear Medicine and Molecular Imaging (SNMMI) have jointly developed a practice parameter on selective internal radiation therapy (SIRT) or radioembolization for treatment of liver malignancies. Radioembolization is the embolization of the hepatic arterial supply of hepatic primary tumors or metastases with a microsphere yttrium-90 brachytherapy device.Materials and MethodsThe ACR -ABS -ACNM -ASTRO -SIR -SNMMI practice parameter for SIRT or radioembolization for treatment of liver malignancies was revised in accordance with the process described on the ACR website (https://www.acr.org/ClinicalResources/Practice-Parameters-and-Technical-Standards) by the Committee on Practice Parameters—Interventional and Cardiovascular Radiology of the ACR Commission on Interventional and Cardiovascular, Committee on Practice Parameters and Technical Standards—Nuclear Medicine and Molecular Imaging of the ACR Commission on Nuclear Medicine and Molecular Imaging and the Committee on Practice Parameters—Radiation Oncology of the ACR Commission on Radiation Oncology in collaboration with ABS, ACNM, ASTRO, SIR, and SNMMI.ResultsThis practice parameter is developed to serve as a tool in the appropriate application of radioembolization in the care of patients with conditions where indicated. It addresses clinical implementation of radioembolization including personnel qualifications, quality assurance standards, indications, and suggested documentation.ConclusionsThis practice parameter is a tool to guide clinical use of radioembolization. It focuses on the best practices and principles to consider when using radioemboliozation effectively. The clinical benefit and medical necessity of the treatment should be tailored to each individual patient.     

Custom mold applicator high-dose-rate brachytherapy for nonmelanoma skin cancer—An analysis of 273 lesions

PurposeNonmelanoma skin cancer is the most commonly diagnosed malignancy in the United States. A modern version of surface brachytherapy, “topographic applicator brachytherapy” (TAB), can be used to treat early-stage nonmelanoma skin cancer (ES-NMSC). The purpose of this study was to evaluate the acute toxicity, chronic toxicity, and recurrence rates of patients with ES-NMSC treated with TAB.Methods and MaterialsFrom 2010 to 2013, 172 patients with 273 ES-NMSC tumors were consecutively treated with TAB. A custom applicator was created using a thermoplastic mold with Harrison Anderson Mick applicators. Dose fractionation schemes included 40 Gy in eight fractions delivered twice per week or 48 Gy in 16 fractions delivered four times per week.ResultsOf the 273 tumors treated, 23.8% were located on the nose, 54.2% were basal cell carcinoma, 76.2% were Stage I, 89.3% were treated definitively, 98.9% completed treatment, and 75.5% received 40 Gy in eight fractions. Median followup was 25.0 months (0.5–71.0 months). Maximum acute toxicity was G0, 0.4%; G1, 33.3%; G2, 48.7%; G3, 12.1%; and G4, 5.1%. Local recurrence was 4.8% at 25 months, with median time to recurrence being 9 months. There was no regional or distant metastasis documented during the followup. Chronic toxicities included erythema (4.4%), chronic ulceration (4.0%), telangiectasia (2.6%), and pigmentation changes (2.2%).ConclusionsTAB was able to provide excellent local control (95.2%) with low rates of Grades 3 and 4 toxicities for treatment of ES-NMSC. TAB is a reasonable alternative to surgical resection when there is concern of poor cosmesis/wound healing.     

Phase I–II trial of perioperative high-dose-rate brachytherapy in oral cavity and oropharyngeal cancer

BackgroundTo determine the feasibility of combined perioperative high-dose-rate brachytherapy (PHDRB) and intermediate-dose external beam radiation therapy (EBRT) as an alternative to full-dose adjuvant EBRT in patients with unirradiated squamous cell cancer (SCC) of the oral cavity and oropharynx.Methods and MaterialsForty patients were treated with surgical resection and PHDRB. PHDRB dose was 4 Gy b.i.d. × 4 (16 Gy) for R0 resections and 4 Gy b.i.d. × 6 (24 Gy) for R1 resections, respectively. External beam radiotherapy (45 Gy in 25 fractions) was added postoperatively. Patients with Stage III, IVa tumors, and some recurrent cases received concomitant cisplatin–paclitaxel chemotherapy during EBRT.ResultsThe rate of protocol compliance was 97.5%. Eleven patients (27.5%) developed RTOG Grade 3 or greater toxicity. Four patients (10%) presented complications requiring a major surgical procedure (RTOG 4), and one patient died of bleeding (RTOG 5). Three complications (7.5%) occurred in the perioperative period, and 8 (20.0%) occurred more than 3 months after the completion of the treatment program. Severe complications were more frequent in posteriorly located implants than in anterior implants (p = 0.035). After a median follow-up of 50 months for living patients (range, 2.5–86.1+), the 7-year actuarial rates of local and locoregional control were 86% and 82%, respectively; and the 7-year disease-free survival and overall survival rates were 50.4% and 52.3%, respectively.ConclusionsPHDRB can be integrated into the management of patients with resected cancer of the oral cavity who are candidates to receive postoperative radiation or chemoradiation. The local control and toxicity rates were similar to those expected after standard chemoradiation. PHDRB was associated with high toxicity in posterior locations, and the scheduled PHDRB dose was shifted to the closest lower level.     

Can postmortem computed tomography detect antemortem hypoxic–ischemic encephalopathy?

The purpose of this study was to evaluate the usefulness of brain postmortem computed tomography (PMCT) findings for the detection of global hypoxia or hypoperfusion leading to hypoxic–ischemic encephalopathy (HIE) prior to death. Cadavers of individuals who died from non-traumatic causes were subjected to PMCT and pathological autopsy. Cases with an episode of cardiopulmonary arrest, hypoxia, or hypoperfusion that required intensive respiratory management at least 24 h before death and exhibited findings of HIE in conventional autopsy (HIE group, n = 6) were compared with those without such episodes prior to death (control group; overall, n = 37; age-matched, n = 8) with regard to four parameters: (1) width of the central sulcus (CS), (2) attenuation difference at the basal ganglia (BG) level, (3) attenuation difference between cerebral gray matter (GM) and cerebral white matter (WM), and (4) attenuation difference between cerebellar GM and cerebral GM. The results revealed significant differences in the width of the CS (P < 0.001), attenuation difference at the BG level (P < 0.001), and attenuation difference between cerebral GM and cerebral WM (P = 0.009) between the HIE group and the overall control group. When the age-matched control group and the HIE group were compared, there was a significant difference in the width of the CS (P = 0.026) and attenuation difference at the BG level (P < 0.001). Our results suggest that effacement of the sulcus of the cerebral hemisphere and the loss of contrast at the BG level on brain PMCT indicate the existence of HIE prior to death.     

Leucocyte scintigraphy or computed tomography for the febrile post-operative patient?

Objective: The optimal initial investigation for the post-operative patient with suspected occult intra-abdominal sepsis is controversial, although the diagnostic accuracy of a variety of techniques is known. Our objective is to determine which investigation has the greatest positive effect on patient management. Methods and patients: We reviewed 67 consecutive post-operative patients investigated for suspected occult sepsis retrospectively and analysed the sequence of investigations required to achieve the diagnosis depending on the choice of initial investigation, and the interval between initiating investigations and performing definitive percutaneous drainage. Results: Forty patients had scintigraphy as the initial investigation and 21 of these went on to require CT. None of the 27 patients who had CT as the initial investigation required any other imaging (X² = 20.6, P < 0.0001) and appropriate percutaneous drainage was ofered immediately. Conversely, the average interval to drainage in those who had scintigraphy first was 3.1 days. Fourteen out of 20 patients (70%) who had scintigraphy as the initial investigation following recent surgery, and 7 of 20 (35%) following old surgery, needed subsequent CT. None of the 20 and 7 patients in the recent and old surgery groups respecitvely who had CT initially required further imaging. Conclusion: Our results suggest recommending CT as the initial investigation in the early post-operative period as this will reduce the total number of investigations required to achieve the diagnosis and the time to definitive drainage. In the late post-operative period, scintigraphy will resolve the majority of problems.     

Optimisation of multislice computed tomography protocols in angio–CT examinations

PURPOSE: The aim of this paper is to explain a general procedure for the optimisation of multislice computed tomography (MSCT) protocols. MATERIALS AND METHODS: Four angio-CT protocols with a GE LightSpeed Plus 4-slice CT scanner were considered. Effective doses were computed for a sample of patients. First the dose was optimised for arterial-phase scans on a standard patient and adapted to the weight of individual patients with a scaling factor. RESULTS: The mean effective dose for an angio-CT examination ranged from 18.8 mSv to 28.8 mSv, depending on the protocol adopted. Following the optimisation procedure, we drew up a table indicating tube current values for each patient weight. Calculation of the effective dose before and after the optimisation procedure revealed a dose reduction of about 40%. CONCLUSIONS: Angio-CT examinations deliver high doses, but these doses can be reduced without affecting image quality.