The clinical year dilemma: Examining the stressors and alternatives of pre-radiology training.

Since its reinstatement in 1997, the effectiveness of the clinical year prior to radiology residency has been a contentious topic concerning its role in cultivating skilled radiologists. This review evaluates the limitations of the one-year internship and explores alternative approaches. Utilizing databases such as PubMed, Google Scholar, and Scopus, this study identified pertinent articles that aligned with the inclusion criteria for post-graduate year 1 (PGY-1) training before radiology residency. Through a qualitative analysis of the literature, the review identifies prevalent themes concerning the drawbacks of the preliminary clinical year and potential alternative strategies. Many current trainees express skepticism about the value of the clinical year, noting a disconnect between its generalist nature and the specialized demands of subsequent radiology training. Interns felt uncertain about radiology exam indications and found radiology departments to be unapproachable, reflecting the need for alternative educational strategies to improve the preparedness and confidence of radiology interns as they transition from academic environments to clinical practice. The preparatory clinical year prior to entering radiology residency presents a mix of utility, along with alternative approaches to structuring this year. These alternatives include incorporating it into the undergraduate medical curriculum, restructuring or designing radiology-focused clinical years, and reevaluating the overall effectiveness of the clinical year in training.

The Practicality of Post-mortem Imaging in Prenatal, Perinatal, and Pediatric Cases.

The essential role of the autopsy is seen in its contributions to medical care, scientific research, and family counseling. Major contributions are also noted in forensic pathology as a means to determine cause-of-death for legal and medical experts. However, autopsy acceptance rates are quite low due to an array of reasons including delayed burials, faith, and moral burdening. Thus, non-invasive post-mortem imaging strategies are becoming increasingly popular. The objective of this literature review is to evaluate the strengths and weaknesses of numerous post-mortem imaging modalities and consider their benefits over the traditional autopsy. The need for expertise in image interpretation for pediatric and perinatal cases is also discussed. A variety of publications, totaling 32 pieces, were selected from available literature on the basis of relevance. These articles studied various perinatal and pediatric post-mortem imaging strategies and their applications in clinical practice. Key strategies include post-mortem MRI, post-mortem CT, fetal post-mortem sonography, post-mortem computed tomographic angiography, and three-dimensional surface scanning. There is a general consensus that no standard model for post-mortem imaging currently exists in the United States and European countries. Amongst the imaging modems studied, post-mortem MRI has been acknowledged to show the greatest promise in diagnostic accuracy for fetal age groups. Most studies demonstrated that post-mortem CT had limited use for autopsy. Post-mortem imaging strategies for autopsy have high potential given their minimal invasiveness and increasing popularity. Furthermore, it is vital to crafting a global standard procedure for post-mortem imaging for prenatal, perinatal, and pediatric cases to better understand the cause of death, decomposition factors, and effects in-utero, and to provide an alternative to traditional autopsy.

A Primer to Cost-Effectiveness Analysis in Breast Cancer Imaging: A Review of the Literature.

Currently, there is a multitude of methods for evaluating the costs and benefits of programs, tools, etc. While cost-benefit analysis (CBA) is commonly used, cost-effectiveness analysis (CEA) is a more appropriate method of evaluation in clinical contexts, such as radiology practices, as CEAs use units such as life years gained as opposed to money (as is the case for CBAs). This review examines CEAs performed within the past 15 years to highlight their applications and key findings in the context of medical imaging. In total, 20 articles published between 2006 and 2022 were identified using a PubMed search for keywords including "cost-effectiveness analysis," "breast cancer," and "medical imaging," with studies lacking a substantial discussion of CEA or a related topic being excluded. CEAs have traditionally been criticized for lack of a standard methodology, despite their utility in the detection and treatment of various pathologies. Although mammography and magnetic resonance imaging (MRI) are the preferred and cost-effective imaging modalities for breast cancer, other imaging modalities, such as contrast-enhanced mammography and digital breast tomosynthesis, may be more cost-effective in the appropriate clinical context. Different combinations of mammography and MRI screenings for certain breast cancers may also prove to be more cost-effective compared to current mammography/MRI screening schedules. While CEA has shown potential utility in estimating the costs (per unit of health gained) of different imaging tools, CEA risks ignoring important outcomes not included in the analysis and cannot address if the benefits of the imaging tool exceed its costs, as a CBA would, suggesting the need for combining several economic evaluations for a more complete understanding.

Update on the limited sensitivity of computed tomography relative to RT-PCR for COVID-19: a systematic review.

Purpose: The global and ongoing COVID-19 outbreak has compelled the need for timely and reliable methods of detection for SARS-CoV-2 infection. Although reverse transcription-polymerase chain reaction (RT-PCR) has been widely accepted as a reference standard for COVID-19 diagnosis, several early studies have suggested the superior sensitivity of computed tomography (CT) in identifying SARS-CoV-2 infection. In a previous systematic review, we stratified studies based on risk for bias to evaluate the true sensitivity of CT for detecting SARS-CoV-2 infection. This study revisits our prior analysis, incorporating more current data to assess the sensitivity of CT for COVID-19. Material and methods: The PubMed and Google Scholar databases were searched for relevant articles published between 1 January 2020, and 25 April 2021. Exclusion criteria included lack of specification regarding whether the study cohort was adult or paediatric, whether patients were symptomatic or asymptomatic, and not identifying the source of RT-PCR specimens. Ultimately, 62 studies were included for systematic review and were subsequently stratified by risk for bias using the QUADAS-2 quality assessment tool. Sensitivity data were extracted for random effects meta-analyses. Results: The average sensitivity for COVID-19 reported by the high-risk-of-bias studies was 68% [CI: 58, 80; range: 38-96%] for RT-PCR and 91% [CI: 87, 96; range: 47-100%] for CT. The average sensitivity reported by the low-risk-of-bias studies was 84% [CI: 0.75, 0.94; range: 70-97%] for RT-PCR and 78% [CI: 71, 0.86; range: 44-92%] for CT. Conclusions: On average, the high-risk-of bias studies underestimated the sensitivity of RT-PCR and overestimated the sensitivity of CT for COVID-19. Given the incorporation of recently published low-risk-of-bias articles, the sensitivities according to low-risk-of-bias studies for both RT-PCR and CT were higher than previously reported.

Applications and challenges of artificial intelligence in diagnostic and interventional radiology.

Purpose: Machine learning (ML) and deep learning (DL) can be utilized in radiology to help diagnosis and for predicting management and outcomes based on certain image findings. DL utilizes convolutional neural networks (CNN) and may be used to classify imaging features. The objective of this literature review is to summarize recent publications highlighting the key ways in which ML and DL may be applied in radiology, along with solutions to the problems that this implementation may face. Material and methods: Twenty-one publications were selected from the primary literature through a PubMed search. The articles included in our review studied a range of applications of artificial intelligence in radiology. Results: The implementation of artificial intelligence in diagnostic and interventional radiology may improve image analysis, aid in diagnosis, as well as suggest appropriate interventions, clinical predictive modelling, and trainee education. Potential challenges include ethical concerns and the need for appropriate datasets with accurate labels and large sample sizes to train from. Additionally, the training data should be representative of the population to which the future ML platform will be applicable. Finally, machines do not disclose a statistical rationale when expounding on the task purpose, making them difficult to apply in medical imaging. Conclusions: As radiologists report increased workload, utilization of artificial intelligence may provide improved outcomes in medical imaging by assisting, rather than guiding or replacing, radiologists. Further research should be done on the risks of AI implementation and how to most accurately validate the results.

Has Hypofractionated Whole-Breast Radiation Therapy Become the Standard of Care in the United States? An Updated Report from National Cancer Database.

INTRODUCTION/BACKGROUND: We aimed to update the previous evaluation of hypofractionated whole-breast irradiation (HF-WBI) use over time in the United States and factors related to its adoption for patients undergoing a lumpectomy from 2004 to 2016. MATERIALS AND METHODS: Among the patients who underwent a lumpectomy, we identified 688,079 patients with early-stage invasive breast cancer and 248,218 patients with ductal carcinoma in situ in the National Cancer Database from 2004 to 2016. We defined HF-WBI as 2.5 to 3.33 Gy/fraction to the breast and conventional fractionated whole-breast irradiation as 1.8 to 2.0 Gy/fraction. We evaluated the trend of HF-WBI use and examined factors associated with HF-WBI use using logistic regression models. RESULTS: Among invasive cancer patients, the use of HF-WBI increased exponentially from 0.7% in 2004 to 15.6% in 2013 and then to 38.1% in 2016. Among patients with ductal carcinoma in situ, the use of HF-WBI has increased significantly from 0.42% in 2004 to 13.4% in 2013 and then to 34.3% in 2016. Factors found to be associated with HF-WBI use included age, patient geographical location, race/ethnicity, tumor stage, grade, treating facility type, and volume. CONCLUSION: HF-WBI use in the United States has more than doubled from 2013 to 2016. Although its use is close to that of conventional fractionated whole-breast irradiation, HF-WBI is still far from the preferred standard of care in the United States. We identified several patient and facility factors that can impact the uptake of HF-WBI treatment. Microabstract Using the National Cancer Database from 2004 to 2016, we evaluated the trend of hypofractionated whole-breast radiation therapy use and factors associated with use. Use in the United States has more than doubled from 2013 to 2016, but it has not become the standard of care. We identified several patient and facility factors that impact the uptake of hypofractionated whole-breast radiation therapy treatment.

A Review of Applications of Machine Learning in Mammography and Future Challenges.

BACKGROUND: The aim of this study is to systematically review the literature to summarize the evidence surrounding the clinical utility of artificial intelligence (AI) in the field of mammography. Databases from PubMed, IEEE Xplore, and Scopus were searched for relevant literature. Studies evaluating AI models in the context of prediction and diagnosis of breast malignancies that also reported conventional performance metrics were deemed suitable for inclusion. From 90 unique citations, 21 studies were considered suitable for our examination. Data was not pooled due to heterogeneity in study evaluation methods. SUMMARY: Three studies showed the applicability of AI in reducing workload. Six studies demonstrated that AI can aid in diagnosis, with up to 69% reduction in false positives and an increase in sensitivity ranging from 84 to 91%. Five studies show how AI models can independently mark and classify suspicious findings on conventional scans, with abilities comparable with radiologists. Seven studies examined AI predictive potential for breast cancer and risk score calculation. Key Messages: Despite limitations in the current evidence base and technical obstacles, this review suggests AI has marked potential for extensive use in mammography. Additional works, including large-scale prospective studies, are warranted to elucidate the clinical utility of AI.

The benefit of intravenous thrombolysis prior to mechanical thrombectomy within the therapeutic window for acute ischemic stroke.

The increase in risk for acute ischemic stroke (AIS) with age is well established. If not treated properly and promptly, AIS can result in permanent neurological damage and even death. This literature review assesses the clinical outcomes of AIS patients treated with both intravenous thrombolysis (IVT) prior to mechanical thrombectomy (MT) compared to those treated solely with mechanical thrombectomy. Randomized controlled trials (RCTs) and meta-analyses published from 2015 to 2020 and available on PubMed were selected for review, and their quantitative and qualitative findings were extrapolated and summarized. Post-hoc analyses from ASTER and ETIS trials were reviewed as well as the impact of combined therapy and monotherapy on large vessel occlusions (LVO). Clinical outcomes in all examined trials demonstrated significant successful reperfusion as well as a higher rate of functional independence at 90 days for IVT prior to MT. Concerns of thrombus fragility, safety and cost effectiveness of dual therapy are also addressed. Based on these findings, we recommend the use of IVT as a pretreatment procedure to MT for AIS when eligible for IVT. Recent articles further strengthen this recommendation and provide new insights that IVT prior to MT is especially beneficial for patients presenting with multiple LVOs localized to the anterior intracranial circulation. Additional multi-center RCTs are necessary for further analysis of statistical outcomes demonstrating mixed effects.

Reviewing applications of structural and functional MRI for bipolar disorder.

Bipolar disorders (BDs) represent one of the leading causes of disability and morbidity globally. The use of functional magnetic resonance imaging (fMRI) is being increasingly studied as a tool to improve the diagnosis and treatment of BDs. While morphological biomarkers can be identified through the use of structural magnetic resonance imaging (sMRI), recent studies have demonstrated that varying degrees of both structural and functional impairments indicate differing bipolar subtypes. Within fMRI, resting-state fMRI has specifically drawn increased interest for its capability to detect different neuronal activation patterns compared to task-based fMRI. This study aims to review recently published literature regarding the use of fMRI to investigate structural-functional relationships in BD diagnosis and specifically resting-state fMRI to provide an opinion on fMRI's modern clinical application. All sources in this literature review were collected through searches on both PubMed and Google Scholar databases for terms such as 'resting-state fMRI' and 'functional neuroimaging biomarkers of bipolar disorder'. While there are promising results supporting the use of fMRI for improving differential accuracy and establishing clinically relevant biomarkers, additional evidence will be required before fMRI is considered a dependable component of the overall BD diagnostic process.

Management of Challenging Radioiodine Treatment Protocols: A Case Series and Review of the Literature.

Radioactive iodine (RAI) therapy with 131I is the standard of care for treatment in many patients with differentiated thyroid cancer. Because 131I is typically administered as a pill, and much of its radioactivity is excreted via the urine, there can be challenges in patients who cannot swallow pills, absorb iodine via the gastrointestinal tract, or eliminate RAI via the urine (i.e., dialysis patients and patients with renal failure). In this article, we present 3 cases in which the standard 131I treatment protocol for thyroid cancer could not be used because of these challenges, and we discuss the strategies used to overcome them. Provider collaboration and treatment customization are critical in overcoming patient-specific challenges.

The Limited Sensitivity of Chest Computed Tomography Relative to Reverse Transcription Polymerase Chain Reaction for Severe Acute Respiratory Syndrome Coronavirus-2 Infection: A Systematic Review on COVID-19 Diagnostics.

OBJECTIVES: Several studies suggest the sensitivity of chest computed tomography (CT) is far greater than that of reverse transcription polymerase chain reaction (RT-PCR) in diagnosing COVID-19 patients, and therefore, CT should be included as a primary diagnostic tool. This systematic review aims to stratify studies as high or low risk of bias to determine the true sensitivity of CT for severe acute respiratory syndrome coronavirus-2 infection according to the unbiased (low risk) studies, a topic of particular importance given the insufficient quantity of RT-PCR kits in many countries. We focus on sensitivity as that is the chief advantage perceived of CT. MATERIALS AND METHODS: This systematic review involved searching the PubMed and Google Scholar databases for articles conducted and published between January 1 and April 15, 2020. The quality assessment tool QUADAS-2 was used to stratify studies according to their risk of bias, and exclusion criteria included not providing the information deemed relevant for such a stratification, such as not indicating if the patients were symptomatic or asymptomatic, or identifying the source of the specimen for the reference standard, RT-PCR (eg, nasal, oropharyngeal, etc). Sensitivity values were then extracted, and random effects meta-analyses were performed. RESULTS: Of 641 search results, 37 studies (n = 9610 patients) were included in the analysis. The mean sensitivity of RT-PCR for COVID-19 reported by the biased studies was 70% (n = 5409/7 studies; 95% confidence interval [CI], 43-97; I = 99.1%), compared with 78% by unbiased studies (n = 534/4 studies; 95% CI, 69-87, I = 89.9%). For chest CT, the mean sensitivity reported by biased studies was 94% (n = 3371 patients/24 studies; 95% CI, 92-96; I = 93.1%), compared with 75% by unbiased studies (n = 957/10 studies; 95% CI, 67-83; I = 89.5%). CONCLUSIONS: The difference between the sensitivities of CT and RT-PCR for severe acute respiratory syndrome coronavirus-2 infection is lower than previously thought, as after stratifying the studies, the true sensitivity for CT based on the unbiased studies is limited.

Diagnostic Tools for Coronavirus Disease (COVID-19): Comparing CT and RT-PCR Viral Nucleic Acid Testing.

OBJECTIVE. Multiple studies suggest CT should be a primary diagnostic tool for coronavirus disease (COVID-19) because they reported sensitivities with CT far superior to that of reverse transcriptase polymerase chain reaction (RT-PCR) testing. This review aimed to assess these reports and found chest CT to have a clinical utility that is limited, particularly for patients who show no symptoms and patients who are screened early in disease progression. CONCLUSION. CT has limited sensitivity for COVID-19 and a lower specificity than RT-PCR testing, and it carries a risk of exposing providers to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Chest CT should be considered a supplemental diagnostic tool, particularly for patients who show symptoms.

The clinical utility of imaging methods used to measure hypoxia in cervical cancer.

While it is well-established that hypoxia is a major factor that affects clinical outcomes in cervical cancer, widespread usage of clinically available methods to detect and evaluate hypoxia during the course of treatment have not been established. This review compares these methods, summarizes their strengths and weaknesses, and assesses the pathways for their useful employment to alter clinical practice. We conducted a search on PubMed for literature pertaining to imaging hypoxic cervical cancer, and implemented keywords related to oxygen measurement tools to improve the relevance of the search results.Oxygenation level-dependent applications of MRI have demonstrated hypoxia-induced radioresistance, and changes in cervix tumor oxygenation from hyperoxic therapy.The hypoxic areas within tumors can be indirectly identified in dynamic contrast-enhanced images, where they generally display low signal enhancement, and diffusion-weighted images, which demonstrates areas of restricted diffusion (which correlates with hypoxia). Positron emmision tomography, used independently and with other imaging modalities, has demonstrated utility in imaging hypoxia through tracers specific for low oxygen levels, like Cu-ATSM tracers and nitroimidazoles. Detecting hypoxia in the tumors of patients diagnosed with cervical cancer via medical imaging and non-imaging tools like electron paramagnetic resonance oximetry can be utilized clinically, such as for guiding radiation and post-treatment surveillance, for a more personalized approach to treatment. The merits of these methods warrant further investigation via comparative effectiveness research and large clinical trials into their clinical applications.

A novel mouse model of sporadic colon cancer induced by combination of conditional Apc genes and chemical carcinogen in the absence of Cre recombinase.

Although valuable insights into colon cancer biology have been garnered from human colon cancer cell lines and primary colonic tissues, and animal studies using human colon cancer xenografts, immunocompetent mouse models of spontaneous or chemically induced colon cancer better phenocopy human disease. As most sporadic human colon tumors present adenomatous polyposis coli (APC) gene mutations, considerable effort has gone into developing mice that express mutant Apc alleles that mimic human colon cancer pathogenesis. A serious limitation of many of these Apc-mutant murine models, however, is that these mice develop numerous tumors in the small intestine but few, if any, in the colon. In this work, we examined three spontaneous mouse models of colon tumorigenesis based upon the widely used multiple intestinal neoplasia (Min) mouse: mice with either constitutive or conditional Apc mutations alone or in combination with caudal-related homeobox transcription factor CDX2P-Cre transgene - either with or without exposure to the potent colon carcinogen azoxymethane. Using the CDX2 promoter to drive Cre recombinase transgene expression effectively inactivated Apc in colonocytes, creating a model with earlier tumor onset and increased tumor incidence/burden, but without the Min mouse model's small intestine tumorigenesis and susceptibility to intestinal perforation/ulceration/hemorrhage. Most significantly, azoxymethane-treated mice with conditional Apc expression, but absent the Cre recombinase gene, demonstrated nearly 50% tumor incidence with two or more large colon tumors per mouse of human-like histology, but no small intestine tumors - unlike the azoxymethane-resistant C57BL/6J-background Min mouse model. As such this model provides a robust platform for chemoprevention studies.

Clinical and Dosimetric Implications of Intrafractional Cylinder Movement During Vaginal Cuff Brachytherapy.

Introduction To quantify the dosimetric and clinical effects of intrafractional cylinder movement in patients receiving high-dose-rate vaginal cuff brachytherapy (VBT) without a formal immobilization device and the implication of motion on institutional clinical outcomes. Methods From 2013-2018, 119 patients were treated with VBT with no formal immobilization device at a single institution. As a quality assessment study, pre-and post-cylinder brachytherapy kilovoltage (kV) images were acquired for 37 fractions in nine consecutive patients who underwent VBT and clinical care representative of institutional practice standards. The D90 and D90 EqD2 were calculated according to each patient's average intrafractional movement throughout the treatment course. The D2cc for organs-at-risk (OARs) were also re-evaluated following the simulated movements. The survival outcomes and toxicity were recorded from the 119 patients. Toxicity was graded as per Common Terminology Criteria for Adverse Events (CTCAE) version 4.0. Results The measured mean ± standard deviation movement was 5.0 mm ± 3.5, with 62% moving caudad. The D90 from each patient's maximum and average movements were lower than the pre-planned doses: 71%, and 89%, respectively. The doses to the OARs were lower than the pre-planned doses. After a median follow-up of 20 months, there were three local recurrences with a median time of 14.5 months (range: 10-31). There were two acute grade 3+ toxicities and one late grade 3+ toxicity. There was a moderate correlation (r = 0.40) between body mass index (BMI) and intrafraction movement with caudad being more common in smaller BMIs (p = 0.0216). Conclusions Intrafractional vaginal cylinder movement without a table fixation device is about 5.0 mm, with the majority of movements moving caudad. While institutional outcomes suggest that local control may not be compromised, consideration of more formal immobilization devices is warranted, especially for those patients with lower BMIs.

Safety and Efficacy of Accelerated Hypofractionation and Stereotactic Body Radiation Therapy for Hepatocellular Carcinoma Patients With Varying Degrees of Hepatic Impairment.

PURPOSE: To report the toxicities and outcomes for stereotactic body radiation therapy (SBRT) and accelerated hypofractionated radiation therapy (AHRT) in patients with Child-Pugh (CP) class A, B, or C and albumin-bilirubin (ALBI) score 1, 2, or 3 hepatocellular carcinoma. METHODS AND MATERIALS: We retrospectively reviewed the data from 146 patients with hepatocellular carcinoma who had undergone SBRT (50 Gy in 5 fractions) or AHRT (45 Gy in 18 fractions). The primary endpoint was liver toxicity, defined as an increase in the CP score of ≥2 within 6 months of radiation therapy. The secondary endpoints of ALBI change, overall survival, and local control were also calculated. RESULTS: The median follow-up was 23 months (range 1-59). Most received SBRT (72%), and 28% received AHRT. Of all 146 patients, 45 (31%) had a CP score elevation of ≥2 within 6 months of radiation therapy (RT) (27 patients [28%] with baseline CP-A/B7 and 18 [35%] with baseline CP-B8/B9/C cirrhosis; P = .45). On multivariate analysis, neither baseline CP nor ALBI score was predictive of toxicity. No patient with a decline in liver functionality of CP ≥2 within 6 months of RT returned to baseline at later time points. Eleven grade 4 toxicities were observed. The mean change in the raw ALBI score at ∼6 months was similar for all baseline ALBI groups. Twenty-two patients underwent orthotopic liver transplantation after RT, 13 of whom had baseline CP-B8/B9/C liver functionality. For all patients, the 1- and 2-year treated-lesion local control was greater for SBRT than for AHRT (2-year 94% vs 65%, P < .0001). CONCLUSIONS: The tolerability of SBRT or AHRT as measured by a CP score decline of ≥2 within 6 months of RT was similar across baseline liver functionality groups. Compared with AHRT, SBRT was associated with superior local control. Because the true tolerability of limited-volume RT for patients with CP-B or CP-C cirrhosis is unknown, prospective trials validating its safety and efficacy are warranted.

Utilization trend and regimens of hypofractionated whole breast radiation therapy in the United States.

PURPOSE: We aimed to evaluate the adoption of hypofractionated whole-breast irradiation (HF-WBI) over time and factors related to its adoption for patients undergoing lumpectomy. We also examined whether HF-WBI can increase the overall use of radiotherapy. METHODS: Using data from the National Cancer Database between 2004 and 2013, we identified 528,051 invasive and 190,431 ductal carcinoma in situ (DCIS) patients who underwent lumpectomy. HF-WBI was defined as 2.5-3.33 Gy/fraction to the breast, whereas conventional therapy (CF-WBI) was defined as 1.8-2.0 Gy/fraction. RESULTS: The usage of HF-WBI among invasive cancer patients increased from 0.7% in 2004 to 15.6% in 2013, and among DCIS patients, HF-WBI increased from 0.4% in 2004 to 13.4% in 2013. However, these changes only lead to a slight increase in the overall use of radiotherapy. Interestingly, for DCIS patients who lived ≥50 miles from hospitals, the uptake of HF-WBI translated to a moderate increase in the overall use of radiotherapy (58% in 2004 to 63% in 2013). Multivariable logistic regression showed that older age, node-negative or smaller tumor, living in mountain states, rural area, or ≥50 miles from hospitals, and treated in large or academic cancer centers were associated with elevated HF-WBI use. The median duration of finishing radiotherapy for HF-WBI was 26 days, compared to 47 days for CF-WBI. CONCLUSIONS: Although HF-WBI can save 3 weeks of patient time, its adoption remained low in the US. There was only a slight increase in the overall use of radiotherapy among patients undergoing lumpectomy.

Volumetric-modulated arc radiotherapy for pancreatic malignancies: dosimetric comparison with sliding-window intensity-modulated radiotherapy and 3-dimensional conformal radiotherapy.

Volumetric-modulated arc radiotherapy (VMAT) is an iteration of intensity-modulated radiotherapy (IMRT), both of which deliver highly conformal dose distributions. Studies have shown the superiority of VMAT and IMRT in comparison with 3-dimensional conformal radiotherapy (3D-CRT) in planning target volume (PTV) coverage and organs-at-risk (OARs) sparing. This is the first study examining the benefits of VMAT in pancreatic cancer for doses more than 55.8 Gy. A planning study comparing 3D-CRT, IMRT, and VMAT was performed in 20 patients with pancreatic cancer. Treatments were planned for a 25-fraction delivery of 45 Gy to a large field followed by a reduced-volume 8-fraction external beam boost to 59.4 Gy in total. OARs and PTV doses, conformality index (CI) deviations from 1.0, monitor units (MUs) delivered, and isodose volumes were compared. IMRT and VMAT CI deviations from 1.0 for the large-field and the boost plans were equivalent (large field: 0.032 and 0.046, respectively; boost: 0.042 and 0.037, respectively; p > 0.05 for all comparisons). Both IMRT and VMAT CI deviations from 1.0 were statistically superior to 3D-CRT (large field: 0.217, boost: 0.177; p < 0.05 for all comparisons). VMAT showed reduction of the mean dose to the boost PTV (VMAT: 61.4 Gy, IMRT: 62.4 Gy, and 3D-CRT: 62.3 Gy; p < 0.05). The mean number of MUs per fraction was significantly lower for VMAT for both the large-field and the boost plans. VMAT delivery time was less than 3 minutes compared with 8 minutes for IMRT. Although no statistically significant dose reduction to the OARs was identified when comparing VMAT with IMRT, VMAT showed a reduction in the volumes of the 100% isodose line for the large-field plans. Dose escalation to 59.4 Gy in pancreatic cancer is dosimetrically feasible with shorter treatment times, fewer MUs delivered, and comparable CIs for VMAT when compared with IMRT.