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1.
Semin Radiat Oncol ; 34(1): 4-13, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-38105092

RESUMO

MRI-guided radiation therapy (MRgRT) is an emerging, innovative technology that provides opportunities to transform and improve the current clinical care process in radiation oncology. As with many new technologies in radiation oncology, careful evaluation from a healthcare economic and policy perspective is required for its successful implementation. In this review article, we describe the current evidence surrounding MRgRT, framing it within the context of value within the healthcare system. Additionally, we highlight areas in which MRgRT may disrupt the current process of care, and discuss the evidence thresholds and timeline required for the widespread adoption of this promising technology.


Assuntos
Radioterapia (Especialidade) , Humanos , Imageamento por Ressonância Magnética , Atenção à Saúde
2.
JAMA Netw Open ; 6(12): e2345906, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-38039002

RESUMO

Importance: Novel hormonal therapy (NHT) agents have been shown to prolong overall survival in numerous randomized clinical trials for patients with advanced prostate cancer (PCa). There is a paucity of data regarding the pattern of use of these agents in patients from different racial and ethnic groups. Objective: To assess racial and ethnic disparities in the use of NHT in patients with advanced PCa. Design, Setting, and Participants: This cohort study comprised all men diagnosed with de novo advanced PCa (distant metastatic [M1], regional [N1M0], and high-risk localized [N0M0] per Systemic Therapy in Advancing or Metastatic Prostate Cancer: Evaluation of Drug Efficacy [STAMPEDE] trial criteria) with Medicare Part A, B, and D coverage between January 1, 2011, and December 31, 2017, in a Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database including prescription drug records. Data analysis took place from January through May 2023. Exposures: Race and ethnicity (Black [non-Hispanic], Hispanic, White, or other [Alaska Native, American Indian, Asian, Pacific Islander, or not otherwise specified and unknown]) abstracted from the SEER data fields. Main Outcomes and Measures: The primary outcome was receipt of an NHT agent (abiraterone, enzalutamide, apalutamide, or darolutamide) using a time-to-event approach. Results: The study included 3748 men (median age, 75 years [IQR, 70-81 years]). A total of 312 (8%) were Black; 263 (7%), Hispanic; 2923 (78%), White; and 250 (7%) other race and ethnicity. The majority of patients had M1 disease (2135 [57%]) followed by high-risk N0M0 (1095 [29%]) and N1M0 (518 [14%]) disease. Overall, 1358 patients (36%) received at least 1 administration of NHT. White patients had the highest 2-year NHT utilization rate (27%; 95% CI, 25%-28%) followed by Hispanic patients (25%; 95% CI, 20%-31%) and patients with other race or ethnicity (23%; 95% CI, 18%-29%), with Black patients having the lowest rate (20%; 95% CI, 16%-25%). Black patients had significantly lower use of NHT compared with White patients, which persisted at 5 years (37% [95% CI, 31%-43%] vs 44% [95% CI, 42%-46%]; P = .02) and beyond. However, there was no significant difference between White patients and Hispanic patients or patients with other race or ethnicity in NHT utilization (eg, 5 years: Hispanic patients, 38% [95% CI, 32%-46%]; patients with other race and ethnicity: 41% [95% CI, 35%-49%]). Trends of lower utilization among Black patients persisted in the patients with M1 disease (eg, vs White patients at 5 years: 51% [95% CI, 44%-59%] vs 55% [95% CI, 53%-58%]). After adjusting for patient, disease, and sociodemographic factors in multivariable analysis, Black patients continued to have a significantly lower likelihood of NHT initiation (adjusted subdistribution hazard ratio, 0.76; 95% CI, 0.61-0.94, P = .01). Conclusions and Relevance: In this cohort study of Medicare beneficiaries with advanced PCa, receipt of NHT agents was not uniform by race, with decreased use observed in Black patients compared with the other racial and ethnic groups, likely due to multifactorial obstacles. Future studies are needed to identify strategies to address the disparities in the use of these survival-prolonging therapies in Black patients.


Assuntos
Disparidades em Assistência à Saúde , Hormônios , Neoplasias da Próstata , Idoso , Humanos , Masculino , Estudos de Coortes , Etnicidade , Medicare , Neoplasias da Próstata/terapia , Estados Unidos , Grupos Raciais , Hormônios/uso terapêutico
4.
Adv Radiat Oncol ; 8(5): 101210, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37152892

RESUMO

Purpose: Advancing equity, diversity, and inclusion in the physician workforce is essential to providing high-quality and culturally responsive patient care and has been shown to improve patient outcomes. To better characterize equity in the field of radiation oncology, we sought to describe the current academic radiation oncology workforce, including any contemporary differences in compensation and rank by gender and race/ethnicity. Methods and Materials: We conducted a retrospective cohort study using data from the Society of Chairs of Academic Radiation Oncology Programs (SCAROP) 2018 Financial Survey. Multivariable logistic regression models were used to identify factors associated with associate or full professor rank. Compensation was compared by gender and race/ethnicity overall and stratified by rank and was further analyzed using multivariable linear regression models. Results: Of the 858 academic radiation oncologists from 63 departments in the United States in the sample, 33.2% were female, 65.2% were White, 27.2% were Asian, and 7.6% were underrepresented in medicine (URiM). There were 44.0% assistant professors, 32.0% associate professors, and 22.8% full professors. Multivariable logistic regression analysis for factors associated with associate or full professor rank did not reveal statistically significant associations between gender or race/ethnicity with academic rank (odds ratio [OR], 0.86; 95% confidence interval [CI], 0.56-1.32; P = .48 for gender; OR, 0.81; 95% CI, 0.5-1.30; P = .37 for Asian vs White; and OR, 0.69; 95% CI, 0.31-1.55; P = .37 for URiM vs White), but CIs were wide due to sample size, and point estimates were <1. Similarly, multivariable linear regression analysis modeling the log relative total compensation did not detect statistically significant differences between radiation oncologists by gender (-1.7%; 95% CI, -6.8% to 3.4%; P = .51 for female vs male) or race/ethnicity (-1.6%; 95% CI, -7.3% to 4.0%; P = .57 for Asian vs White and -3.0%; 95% CI, -12.1% to 6.0%; P = .51 for URiM vs White). Conclusions: The low numbers of women and faculty with URiM race/ethnicity in this radiation oncology faculty sample limits the ability to compare career trajectory and compensation by those characteristics. Given that point estimates were <1, our findings do not contradict larger multispecialty studies that suggest an ongoing need to monitor equity.

5.
Appl Radiat Oncol ; 10(3): 33-40, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34671700

RESUMO

BACKGROUND AND PURPOSE: Stereotactic body radiation therapy (SBRT) has become a standard-of-care option for localized prostate cancer. While prostate SBRT has traditionally been delivered using computed-tomography-guided radiation therapy (CTgRT), MR-imaging-guided radiation therapy (MRgRT) is now available. MRgRT offers real-time soft-tissue visualization and ease of adaptive planning, obviating the need for fiducial markers, and potentially allowing for smaller planning target volume (PTV) margins. Although prior studies have focused on evaluating the cost-effectiveness of MRgRT vs CTgRT from a payor perspective, the difference in provider costs to deliver such treatments remains unknown. This study thus used time-driven activity-based costing (TDABC) to determine the difference in provider resources consumed by delivering prostate SBRT via MRgRT vs CTgRT. METHODS: Data was collected from a single academic institution where prostate SBRT is routinely performed using both CTgRT and MRgRT. Five-fraction SBRT (40 Gy total dose) was assumed to be delivered through volumetric-modulated arc therapy for CTgRT patients, and through step-and-shoot, fixed-gantry intensity-modulated radiation therapy for MRgRT patients. Process maps were constructed for each portion of the radiation delivery process via interviews/surveys with departmental personnel and by measuring CTgRT and MRgRT treatment times. Prior to simulation, only CTgRT patients underwent placement of three gold fiducial markers. Personnel capacity cost rates were calculated by dividing total personnel costs by the annual minutes worked by a given personnel. Equipment costs included both an annualized purchase price and annual maintenance costs. Ultimately, the total costs of care encompassing personnel, space/equipment, and materials were aggregated across the entire chain of care for both CTgRT and MRgRT patients in a base case. RESULTS: Direct costs associated with delivering a 5-fraction course of prostate SBRT were $1,497 higher with MRgRT than with CTgRT - comprised of personnel costs ($210 higher with MRgRT), space/equipment ($1,542 higher with MRgRT), and materials ($255 higher with CTgRT). Only CTgRT patients underwent fiducial placement, which accounted for $591. MRgRT patients were assumed to undergo both CT simulation (for electron density calculation) and MRI simulation, with the former accounting for $168. Mean time spent by patients in the treatment vault per fraction was 20 minutes (range 15-26 minutes) for CTgRT, and 31 minutes (range 30-34 minutes) for MRgRT. Patient time spent during fiducial placement (CTgRT only) was 60 minutes. Modifying the number of fractions treated would result in the cost difference of $1,497 (5 fractions) changing to $441 (1 fraction) or to $2,025 (7 fractions). CONCLUSION: This study provides an approximate comparison of the direct resources required for a radiation oncology provider to deliver prostate SBRT with CTgRT vs MRgRT. We await findings from the currently accruing phase III MIRAGE trial, which is comparing these modalities, and will subsequently measure acute and late genitourinary/gastrointestinal (GU/GI) toxicities, temporal change in quality-of-life outcomes, and 5-year biochemical, recurrence-free survival. Results from studies comparing the efficacy and safety of MRgRT vs CTgRT will ultimately allow us to put this cost difference into context.

6.
Cancer Med ; 10(14): 4734-4742, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34076341

RESUMO

PURPOSE: Though utilization of medical procedures has been shown to vary considerably across the United States, similar efforts to characterize variation in the delivery of radiation therapy (RT) procedures have not been forthcoming. Our aim was to characterize variation in the delivery of common RT procedures in the Medicare population. We hypothesized that delivery would vary significantly based on provider characteristics. METHODS: The Centers for Medicare and Medicaid Services (CMS) Physician and Other Supplier Public Use File was linked to the CMS Physician Compare (PC) database by physician NPI to identify and sum all treatment delivery charges submitted by individual radiation oncologists in the non-facility-based (NFB) setting in 2016. Multivariable logistic regression analysis was carried out to determine provider characteristics (gender, practice rurality, practice region, and years since graduation) that predicted for the delivery of 3D conformal RT (3DCRT), intensity modulated RT (IMRT), stereotactic body RT (SBRT), stereotactic radiosurgery (SRS), low dose rate (LDR) brachytherapy, and high dose rate (HDR) brachytherapy delivery in the Medicare patient population. The overall significance of categorical variables in the multivariable logistic regression model was assessed by the likelihood ratio test (LRT). RESULTS: In total, 1,802 physicians from the NFB practice setting were analyzed. Male gender predicted for greater LDR brachytherapy delivery (OR 8.19, 95% CI 2.58-26.05, p < 0.001), but not greater delivery of other technologies. Metropolitan practice was the only predictor for greater HDR brachytherapy utilization (OR 12.95, 95% CI 1.81-92.60, p = 0.01). Practice region was predictive of the delivery of 3DCRT, SRS and SBRT (p < 0.01, p < 0.001, and p < 0.001, respectively). With the Northeast as the reference region, 3DCRT was more likely to be delivered by providers in the South (OR 1.33, 95% CI 1.09-1.62, p < 0.01) and the West (OR 1.38, 95% CI 1.11-1.71, p < 0.01). At the same time, SRS use was less likely in the Midwest (OR 0.71, 95% CI 0.55-0.91, p < 0.01), South (OR 0.49, 95% CI 0.40-0.61, p < 0.001), and West (OR 0.43, 95% CI 0.34-0.55, p < 0.001). SBRT, on the other hand, was more commonly utilized in the Midwest (OR 2.63, 95% CI 1.13-6.13, p = 0.03), South (OR 3.44, 95% CI 1.58-7.49, p < 0.01), and West (OR 4.87, 95% CI 2.21-10.72, p < 0.001). HDR brachytherapy use was also more likely in the Midwest (OR 1.97, 95% CI 1.11-3.49, p = 0.02) and West (OR 1.87, 95% CI 1.08-3.24, p = 0.03). While the degree held by the billing physician did not predict for delivery of a given procedure, greater years since graduation was related to decreased likelihood of SBRT use (OR 0.98, 95% CI 0.96-0.99, p < 0.001) and increased likelihood of LDR brachytherapy use (OR 1.02, 95% CI 1.00-1.04, p = 0.02). CONCLUSIONS: Substantial geographic variation in the use of specific RT technologies was identified. The degree to which this variation reflects effective care, preference-sensitive care, or supply-sensitive care warrants further investigation.


Assuntos
Medicare , Radio-Oncologistas , Radioterapia (Especialidade)/métodos , Radioterapia/métodos , Braquiterapia/estatística & dados numéricos , Centers for Medicare and Medicaid Services, U.S. , Competência Clínica , Bases de Dados Factuais , Feminino , Humanos , Masculino , Razão de Chances , Padrões de Prática Médica/estatística & dados numéricos , Área de Atuação Profissional , Radio-Oncologistas/estatística & dados numéricos , Radioterapia (Especialidade)/estatística & dados numéricos , Radiocirurgia/estatística & dados numéricos , Radioterapia/estatística & dados numéricos , Dosagem Radioterapêutica , Radioterapia Conformacional/estatística & dados numéricos , Radioterapia de Intensidade Modulada/estatística & dados numéricos , Análise de Regressão , Fatores Sexuais , Estados Unidos
7.
JAMA Netw Open ; 4(2): e2034074, 2021 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-33599771

RESUMO

Importance: The adoption of alternative fractionated radiotherapy regimens for the treatment of patients with cancer and comorbid collagen vascular disease (CVD) is controversial among oncologists because of concerns about potentially severe toxic effects; however, the association between fractionated radiotherapy and toxic effects in the modern era has not been well studied. Objective: To compare acute and late toxic effects among patients with cancer and comorbid CVD who received dose-fractionated radiotherapy. Design, Setting, and Participants: This retrospective cohort study examined 197 adult patients with cancer and CVD who received radiotherapy at a single-institution tertiary academic center over a 12-year period (February 1, 2007, to April 30, 2019), with a median follow-up of 23 months (range, 0-108 months). Data were analyzed from February 1 to August 31, 2020. Exposures: Three dose-fractionated radiotherapy regimens: conventional fractionation (CF; ≤2 Gy per fraction), moderate hypofractionation (MH; >2 Gy to <5 Gy per fraction), and ultrahypofractionation (UH; ≥5 Gy per fraction). Main Outcomes and Measures: The main outcomes were the incidence and severity of acute and late radiotherapy-associated toxic effects, which were assessed separately by dose-fractionation regimen. Toxic effects occurring within 90 days after radiotherapy completion were considered acute, and toxic effects occurring after that 90-day period were considered late. Secondary goals were to identify covariates associated with toxic effects and to characterize the incidence of CVD symptom flares (defined as worsening clinical symptoms and/or worsening results [transient or permanent] on associated blood tests compared with baseline, as documented by managing physicians) after radiotherapy. Results: Of 197 patients with cancer and comorbid CVD (mean [SD] age, 69 [12] years; 134 women [68.0%]; and 149 White participants [75.6%]), 80 patients (40.6%) received CF radiotherapy, 55 patients (27.9%) received MH radiotherapy, and 62 patients (31.5%) received UH radiotherapy. The most common CVD diagnoses were rheumatoid arthritis (74 patients [37.6%]), psoriasis (54 patients [27.4%]), systemic lupus erythematosus (34 patients [17.3%]), and scleroderma (8 patients [4.1%]). The most common radiotherapy sites were the breast (48 patients [24.4%]), thorax (25 patients [12.7%]), central nervous system (24 patients [12.2%]), and prostate (23 patients [11.7%]). Data on acute toxic effects were available for 188 patients (95.4%) and missing for 9 patients (4.6%). Data on late toxic effects were available for 142 patients (72.1%) and missing for 55 patients (27.9%). Over 12 years, the unadjusted incidences of severe acute toxic effects associated with CF, MH, and UH radiotherapy were 5.4% (95% CI, 0.3%-10.5%), 7.4% (95% CI, 0.4%-14.4%), and 1.7% (95% CI, 0%-5.0%), respectively. The incidences of severe late toxic effects associated with CF, MH, and UH radiotherapy were 8.3% (95% CI, 1.3%-15.3%), 0%, and 2.2% (95% CI, 0%-6.4%), respectively. No significant associations were found between severe acute or late toxic effects by dose fractionation regimen. In the multivariable analysis, MH radiotherapy was associated with a lower likelihood of developing late toxic effects (odds ratio [OR], 0.21; 95% CI, 0.05-0.83; P = .03) compared with CF radiotherapy. Those who received UH radiotherapy had a lower likelihood of experiencing late toxic effects (OR, 0.22; 95% CI, 0.04-1.21; P = .08). A total of 19 of 80 patients (23.8%), 15 of 55 patients (27.3%), and 10 of 62 patients (16.1%) experienced CVD symptom flares after receiving CF, MH, and UH radiotherapy, respectively (P = .33). Conclusions and Relevance: In this study, the incidences of unadjusted severe toxic effects over 12 years were less than 10% and were not significantly associated with dose fractionation. When clinically indicated, patients with cancer and comorbid CVD may not require immediate exclusion from the receipt of currently used hypofractionated radiotherapy regimens.


Assuntos
Doenças do Tecido Conjuntivo/epidemiologia , Neoplasias/radioterapia , Lesões por Radiação/epidemiologia , Radioterapia/métodos , Idoso , Idoso de 80 Anos ou mais , Artrite Reumatoide/epidemiologia , Neoplasias da Mama/radioterapia , Comorbidade , Fracionamento da Dose de Radiação , Feminino , Neoplasias de Cabeça e Pescoço/radioterapia , Humanos , Incidência , Neoplasias Pulmonares/radioterapia , Lúpus Eritematoso Sistêmico/epidemiologia , Masculino , Pessoa de Meia-Idade , Neoplasias/epidemiologia , Neoplasias da Próstata/radioterapia , Psoríase/epidemiologia , Hipofracionamento da Dose de Radiação , Lesões por Radiação/etiologia , Radioterapia/efeitos adversos , Estudos Retrospectivos , Escleroderma Sistêmico/epidemiologia
8.
JCO Oncol Pract ; 17(12): e1905-e1912, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-33417480

RESUMO

PURPOSE: Variation in the use of radiation oncology procedures and technologies is poorly characterized. We sought to identify associations between the treatment planning codes used to bill for radiotherapy procedures and the demographic characteristics of the radiation oncologists submitting them. METHODS: The Physician and Other Supplier Public Use File was linked to the Physician Compare database by using the physician National Provider Identifier for the year 2016. Analysis was stratified by practice setting, considering both the freestanding non-facility-based (NFB) setting and the facility-based (FB) setting. Multivariable logistic regression was used to determine provider characteristics (gender, practice rurality, and years since graduation) that predicted for the use of 3D-conformal RT (3DCRT) planning, intensity-modulated RT (IMRT) planning, and brachytherapy planning in the Medicare population. RESULTS: Three thousand twenty-nine physicians were linked for analysis. In both the FB and NFB settings together, male gender predicted for decreased likelihood of 3DCRT planning (OR, 0.70, 95% CI, 0.62 to 0.80, P < .001) and increased likelihood of IMRT planning (OR, 1.35, 95% CI, 1.19 to 1.54, P < .001). Brachytherapy planning was also more likely with increasing years since medical school graduation (OR, 1.03, 95% CI, 1.01 to 1.04, P < .001) in the combined FB and NFB settings. These significant associations persisted when examining the NFB and FB settings individually. In both settings overall, brachytherapy planning was more likely in male providers (OR, 1.75, 95% CI, 1.10 to 2.76, P = .02) and also more likely for providers practicing in metropolitan regions compared with those practicing in rural areas (OR, 3.01, 95% CI, 1.23 to 7.39, P = .02). CONCLUSION: Male gender predicts for utilization of IMRT planning, whereas female gender predicts for utilization of 3DCRT planning. Future research is warranted to better understand the role that provider gender and rurality play in the selection of radiation planning techniques for Medicare patients.


Assuntos
Radioterapia (Especialidade) , Radioterapia Conformacional , Radioterapia de Intensidade Modulada , Idoso , Feminino , Humanos , Masculino , Medicare , Padrões de Prática Médica , Estados Unidos
9.
Eur Urol Oncol ; 4(2): 327-330, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-31411981

RESUMO

Multiple randomized trials have shown a survival benefit to long durations of androgen deprivation therapy (ADT) in patients with Gleason grade group (GG) 4-5 (ie, Gleason score 8-10) prostate cancer (PCa) undergoing definitive external beam radiotherapy (EBRT). We conducted a population-based retrospective study utilizing the complete Surveillance, Epidemiology, and End Results (SEER)-Medicare-linked database from 2008 to 2011, extracting PCa patients of non-Hispanic white (NHW) and African-American (AA) race diagnosed with GG 4-5PCa who received EBRT with or without concomitant ADT. Of 961 patients receiving definitive EBRT, 225 (23.4%) received no ADT, 297 (30.9%) received 1-6mo of ADT, 313 (32.6) received 7-23mo of ADT, and 126 (13.1%) received ≥24mo of ADT. On multinomial logistic regression after inverse probability treatment weighting to balance for differences in other covariates, AA men still had significantly lower odds of receiving 1-6mo of ADT versus no ADT compared with NHW men (odds ratios 0.519 [95% confidence interval, 0.384-0.700]). In conclusion, long-duration ADT is underutilized, with nearly 90% of patients with GG 4-5PCa receiving <24mo of concomitant ADT, and AA men are less likely to receive ADT than NHW men. PATIENT SUMMARY: In this report, we examined the utilization of concomitant androgen deprivation therapy (ADT) among men with high-grade prostate cancer undergoing definitive external beam radiotherapy. We found that long-duration ADT was underutilized overall; moreover, African-American men were less likely to receive concomitant ADT than non-Hispanic white men.


Assuntos
Antagonistas de Androgênios , Neoplasias da Próstata , Idoso , Antagonistas de Androgênios/uso terapêutico , Androgênios , Humanos , Masculino , Medicare , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/radioterapia , Estudos Retrospectivos , Estados Unidos
10.
Int J Radiat Oncol Biol Phys ; 108(2): 430-434, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32890526

RESUMO

PURPOSE: Health systems have increased telemedicine use during the SARS-CoV-2 outbreak to limit in-person contact. We used time-driven activity-based costing to evaluate the change in resource use associated with transitioning to telemedicine in a radiation oncology department. METHODS AND MATERIALS: Using a patient undergoing 28-fraction treatment as an example, process maps for traditional in-person and telemedicine-based workflows consisting of discrete steps were created. Physicians/physicists/dosimetrists and nurses were assumed to work remotely 3 days and 1 day per week, respectively. Mapping was informed by interviews and surveys of personnel, with cost estimates obtained from the department's financial officer. RESULTS: Transitioning to telemedicine reduced provider costs by $586 compared with traditional workflow: $47 at consultation, $280 during treatment planning, $237 during on-treatment visits, and $22 during the follow-up visit. Overall, cost savings were $347 for space/equipment and $239 for personnel. From an employee perspective, the total amount saved each year by not commuting was $36,718 for physicians (7243 minutes), $19,380 for physicists (7243 minutes), $17,286 for dosimetrists (7210 minutes), and $5599 for nurses (2249 minutes). Patients saved $170 per treatment course. CONCLUSIONS: A modified workflow incorporating telemedicine visits and work-from-home capability conferred savings to a department as well as significant time and costs to health care workers and patients alike.


Assuntos
Análise Custo-Benefício , Radioterapia (Especialidade)/métodos , Telemedicina/economia , COVID-19 , Infecções por Coronavirus/epidemiologia , Humanos , Pandemias , Pneumonia Viral/epidemiologia , Radioterapia (Especialidade)/economia , Fatores de Tempo
11.
Int J Radiat Oncol Biol Phys ; 108(4): 999-1007, 2020 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-32603774

RESUMO

PURPOSE: Stereotactic radiosurgery (SRS) historically has been used to treat multiple brain lesions using a multiple-isocenter technique-frequently associated with significant complexity in treatment planning and long treatment times. Recently, given innovations in planning algorithms, patients with multiple brain lesions may now be treated with a single-isocenter technique using fewer total arcs and less time spent during image guidance (though with stricter image guided radiation therapy tolerances). This study used time-driven activity-based costing to determine the difference in cost to a provider for delivering SRS to multiple brain lesions using single-isocenter versus multiple-isocenter techniques. METHODS AND MATERIALS: Process maps, consisting of discrete steps, were created for each phase of the SRS care cycle and were based on interviews with department personnel. Actual treatment times (including image guidance) were extracted from treatment record and verify software. Additional sources of data to determine costs included salary/benefit data of personnel and average list price/maintenance costs for equipment. RESULTS: Data were collected for 22 patients who underwent single-isocenter SRS (mean lesions treated, 5.2; mean treatment time, 30.2 minutes) and 51 patients who underwent multiple-isocenter SRS (mean lesions treated, 4.4; mean treatment time, 75.2 minutes). Treatment time for multiple-isocenter SRS varied substantially with increasing number of lesions (11.8 minutes/lesion; P < .001), but to a much lesser degree in single-isocenter SRS (1.8 minutes/lesion; P = .029). The resulting cost savings from single-isocenter SRS based on number of lesions treated ranged from $296 to $3878 for 2 to 10 lesions treated. The 2-mm planning treatment volume margin used with single-isocenter SRS resulted in a mean 43% increase of total volume treated compared with a 1-mm planning treatment volume expansion. CONCLUSIONS: In a comparison of time-driven activity-based costing assessment of single-isocenter versus multiple-isocenter SRS for multiple brain lesions, single-isocenter SRS appears to save time and resources for as few as 2 lesions, with incremental benefits for additional lesions treated.


Assuntos
Neoplasias Encefálicas/radioterapia , Redução de Custos/economia , Custos de Cuidados de Saúde , Neoplasias Primárias Múltiplas/radioterapia , Radiocirurgia/economia , Algoritmos , Neoplasias Encefálicas/economia , Tomografia Computadorizada de Feixe Cônico , Humanos , Modelos Lineares , Serviço Hospitalar de Engenharia e Manutenção/economia , Neoplasias Primárias Múltiplas/economia , Aceleradores de Partículas/economia , Radiocirurgia/instrumentação , Radiocirurgia/métodos , Planejamento da Radioterapia Assistida por Computador/economia , Radioterapia Guiada por Imagem/economia , Radioterapia Guiada por Imagem/instrumentação , Radioterapia de Intensidade Modulada/economia , Radioterapia de Intensidade Modulada/métodos , Salários e Benefícios/economia , Fatores de Tempo
12.
J Vasc Interv Radiol ; 31(8): 1221-1232, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32674872

RESUMO

PURPOSE: To evaluate the cost effectiveness of incorporating cryoablation in the treatment regimens for uncomplicated bone metastases using radiation therapy (RT) in single-fraction RT (SFRT) or multiple-fraction RT (MFRT) regimens. MATERIALS AND METHODS: A Markov model was constructed using 1-month cycles over a lifetime horizon to compare the cost effectiveness of multiple strategies, including RT followed by RT (RT-RT) for recurrent pain, RT followed by cryoablation (RT-ablation), and cryoablation followed by RT (ablation-RT). RT-RT consisted of 8 Gy in 1 fraction/8 Gy in 1 fraction (SFRT-SFRT) and 30 Gy in 10 fractions/20 Gy in 5 fractions (MFRT-MFRT). Probabilities and utilities were extracted from a search of the medical literature. Costs were calculated from a payer perspective using 2017 Medicare reimbursement in an outpatient setting. Incremental cost effectiveness ratios (ICERs) were calculated using strategies evaluated for willingness-to-pay threshold of $100,000 per quality-adjusted life-year (QALY). To account for model uncertainty, one-way and probabilistic sensitivity analyses were performed. RESULTS: In the base case analysis, SFRT-ablation was cost effective relative to SFRT-SFRT at $96,387/QALY. MFRT-ablation was cost effective relative to MFRT-MFRT at $85,576/QALY. Ablation-SFRT and ablation-MFRT were not cost effective with ICERs >$100,000/QALY. In one-way sensitivity analyses, results were highly sensitive to variation in multiple model parameters, including median survival (base: 9 months), with SFRT-SFRT favored at median survival ≤8.7 months. Probabilistic sensitivity analysis examining SFRT-based regimens showed that SFRT-ablation was preferred in 36.9% of simulations at WTP of $100,000/QALY. CONCLUSIONS: Cryoablation is a potentially cost-effective alternative to reirradiation with RT for recurrent of pain following RT; however, no strategy incorporating initial cryoablation was cost effective.


Assuntos
Neoplasias Ósseas/terapia , Criocirurgia/economia , Custos de Cuidados de Saúde , Cuidados Paliativos/economia , Cirurgia Assistida por Computador/economia , Neoplasias Ósseas/diagnóstico por imagem , Neoplasias Ósseas/mortalidade , Neoplasias Ósseas/secundário , Redução de Custos , Análise Custo-Benefício , Criocirurgia/efeitos adversos , Fracionamento da Dose de Radiação , Humanos , Cadeias de Markov , Modelos Econômicos , Anos de Vida Ajustados por Qualidade de Vida , Radioterapia/economia , Ensaios Clínicos Controlados Aleatórios como Assunto , Retratamento/economia , Cirurgia Assistida por Computador/efeitos adversos , Fatores de Tempo , Resultado do Tratamento
13.
Int J Radiat Oncol Biol Phys ; 108(4): 917-926, 2020 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-32544574

RESUMO

PURPOSE: Oligorecurrent prostate cancer has historically been treated with indefinite androgen deprivation therapy (ADT), although many patients and providers opt to defer this treatment at the time of recurrence given quality-of-life and/or comorbidity considerations. Recently, metastasis-directed therapy (MDT) has emerged as a potential intermediary between surveillance and immediate continuous ADT. Simultaneously, advanced systemic therapy in addition to ADT has also been shown to improve survival in metastatic hormone-sensitive disease. This study aimed to compare the cost-effectiveness of treating oligorecurrent patients with upfront MDT before standard-of-care systemic therapy. METHODS AND MATERIALS: A Markov-based cost-effectiveness analysis was constructed comparing 3 strategies: (1) upfront MDT → salvage abiraterone acetate plus prednisone (AAP) + ADT → salvage docetaxel + ADT; (2) upfront AAP + ADT → salvage docetaxel + ADT; and (3) upfront docetaxel + ADT → salvage AAP + ADT. Transition probabilities and utilities were derived from the literature. Using a 10-year time horizon and willingness-to-pay threshold of $100,000/quality-adjusted life year (QALY), net monetary benefit values were subsequently calculated for each treatment strategy. RESULTS: At 10 years, the base case revealed a total cost of $141,148, $166,807, and $136,154 with QALYs of 4.63, 4.89, and 4.00, respectively, reflecting a net monetary benefit of $322,240, $322,018, and $263,407 for upfront MDT, upfront AAP + ADT, and upfront docetaxel + ADT, respectively. In the probabilistic sensitivity analysis using a Monte Carlo simulation (1,000,000 simulations), upfront MDT was the cost-effective strategy in 53.6% of simulations. The probabilistic sensitivity analysis revealed 95% confidence intervals for cost ($75,914-$179,862, $124,431-$223,892, and $103,298-$180,617) and utility in QALYs (3.85-6.12, 3.91-5.86, and 3.02-5.22) for upfront MDT, upfront AAP + ADT, and upfront docetaxel + ADT, respectively. CONCLUSIONS: At 10 years, upfront MDT followed by salvage AAP + ADT, is comparably cost-effective compared with upfront standard-of-care systemic therapy and may be considered a viable treatment strategy, especially in patients wishing to defer systemic therapy for quality-of-life or comorbidity concerns. Additional studies are needed to determine whether MDT causes a sustained meaningful delay in disease natural history and whether any benefit exists in combining MDT with upfront advanced systemic therapy.


Assuntos
Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/patologia , Radiocirurgia/economia , Terapia de Salvação/economia , Antagonistas de Androgênios/uso terapêutico , Androstenos/uso terapêutico , Antineoplásicos Hormonais/uso terapêutico , Intervalos de Confiança , Análise Custo-Benefício , Docetaxel/uso terapêutico , Humanos , Masculino , Cadeias de Markov , Método de Monte Carlo , Prednisona/uso terapêutico , Neoplasias da Próstata/economia , Anos de Vida Ajustados por Qualidade de Vida , Radiocirurgia/métodos , Terapia de Salvação/métodos , Fatores de Tempo
14.
JCO Oncol Pract ; 16(11): e1378-e1385, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32539652

RESUMO

PURPOSE: Magnetic resonance-guided radiation therapy (MRgRT) has recently become commercially available, offering the opportunity to accurately image and target moving tumors as compared with computed tomography-guided radiation therapy (CTgRT) systems. However, the costs of delivering care with these 2 modalities remain poorly described. With localized unresectable hepatocellular carcinoma as an example, we were able to use time-driven activity-based costing to determine the cost of treatment on linear accelerators with CTgRT compared with MRgRT. MATERIALS AND METHODS: Process maps, informed via interviews with departmental personnel, were created for each phase of the care cycle. Stereotactic body radiation therapy was delivered at 50 Gy in 5 fractions, either with CTgRT using fiducial placement, deep inspiration breath-hold (DIBH) with real-time position management, and volumetric-modulated arc therapy, or with MRgRT using real-time tumor gating, DIBH, and static-gantry intensity-modulated radiation therapy. RESULTS: Direct clinical costs were $7,306 for CTgRT and $8,622 for MRgRT comprising personnel costs ($3,752 v $3,603), space and equipment costs ($2,912 v $4,769), and materials costs ($642 v $250). Increased MRgRT costs may be mitigated by forgoing CT simulation ($322 saved) or shortening treatment to 3 fractions ($1,815 saved). Conversely, adaptive treatment with MRgRT would result in an increase in cost of $529 per adaptive treatment. CONCLUSION: MRgRT offers real-time image guidance, avoidance of fiducial placement, and ability to use adaptive treatments; however, it is 18% more expensive than CTgRT under baseline assumptions. Future studies that elucidate the magnitude of potential clinical benefits of MRgRT are warranted to clarify the value of using this technology.


Assuntos
Radiocirurgia , Radioterapia Guiada por Imagem , Aceleradores de Partículas , Planejamento da Radioterapia Assistida por Computador , Tomografia Computadorizada por Raios X
15.
Front Oncol ; 10: 539, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32373529

RESUMO

Purpose: To assess the optimal planning target volume (PTV) margins for stereotactic body radiotherapy (SBRT) of prostate cancer based on inter- and intra-fractional prostate motion determined from daily image guidance. Methods and Materials: Two hundred and five patients who were enrolled on two prospective studies of SBRT (8 Gy × 5 fractions) for localized prostate cancer treated at a single institution between 2012 and 2017 had complete inter- and intra-fractional shift data available. All patients had scheduled kilovoltage planar imaging during SBRT with rigid registration to intraprostatic fiducials prior to each of four half-arcs delivered per fraction, as well as cone beam CT verification of anatomy prior to each fraction. Inter- and intra- fractional shift data were obtained to estimate the required PTV margins based on the classic van Herk formula. Inter- and intra-fractional motion were compared between patients with and without severe toxicities using the independent two-sample Wilcoxon test. Results: The margins required to account for inter-fractional motion were estimated to be 0.99, 1.52, and 1.45 cm in lateral (LR), longitudinal (SI), and vertical (AP) directions, respectively. The margins required to account for intra-fractional motion were estimated to be 0.19, 0.27, and 0.31 cm in LR, SI and AP directions, respectively. Large intra-fractional shifts were mostly observed in the SI and AP directions, with 2.0 and 5.4% of patients experiencing average intra-fractional motion >3 mm in the SI and AP directions, respectively, compared with none experiencing mean shifts >3 mm in the LR direction. Six patients experienced grade 3 gastrointestinal or genitourinary toxicity. There were no significant differences in mean inter- or intra-fractional motion in any of the cardinal directions compared to patients without severe toxicity (inter-fractional p = 0.46-0.99, intra-fractional p = 0.10-0.84). Conclusion: The inter- and intra-fractional margins estimated from this study are in line with prior reported values. Intra-fractional prostate motion was generally small with larger margins required for the SI and AP directions, notably just slightly exceeding the commonly used 3 mm posterior PTV margin even with realignment between half-arcs. Development of severe toxicity was not significantly associated with the degree of inter- or intra-fractional motion.

16.
JAMA Netw Open ; 2(1): e187377, 2019 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-30681710

RESUMO

Importance: Industry relationships are an important measure of professional advancement; however, the association between physician sex and industry payments in radiation oncology has not been described. Objective: To update the trends in the sex distribution of industry payments in radiation oncology. Design, Setting, and Participants: This retrospective cross-sectional study was conducted between July 1, 2018, and August 31, 2018. It used the publicly available Centers for Medicare & Medicaid Services (CMS) Open Payments program and CMS Physician and Other Supplier Public Use File databases to obtain 2016 industry payment data for US radiation oncologists who reported receiving industry funding in that year (n = 3052). Total monetary value, number of payments, and median payment amounts were determined for each sex in the following categories: research, consulting, honoraria, industry grants, royalty or license, and services other than consulting. Main Outcomes and Measures: Industry payment amounts among 3052 radiation oncologists who reported receiving payments in 2016; association of median payment with the types of payment by sex. Results: Of the total 4483 radiation oncologists who practiced in 2016, 1164 (25.9%) were female and 3319 (74.0%) were male. Industry payments were distributed among 3052 radiation oncologists (68.1%), of whom 715 (23.4%) were female and 2337 (76.6%) were male. The proportion of female radiation oncologists who received at least 1 industry payment was 61.4% (715 of 1164), whereas the proportion of their male counterparts was 70.4% (2337 of 3319). Across all payment types, female radiation oncologists received a smaller percentage of total industry funding than the percentage of female physicians represented in each category. The median payment value was smaller for female radiation oncologists in consulting (-$1000; 95% CI, -$1966.67 to $100.63; P = .005) and honoraria (-$500; 95% CI, -$1071.43 to $0; P = .007). This trend was also observed in research payments, but was not statistically significant (-$135.02; 95% CI, -$476.93 to $6.88; P = .08). Of the $1 347 509 royalty or license payments made to 72 physicians, none was for female radiation oncologists. Conclusions and Relevance: Distribution of industry payments appears to show sex disparity in industry relationships among radiation oncologists; this observation warrants further investigation to determine the underlying reasons and provide avenues for increased parity.


Assuntos
Indústrias/economia , Médicas/economia , Radio-Oncologistas/economia , Remuneração , Centers for Medicare and Medicaid Services, U.S. , Estudos Transversais , Organização do Financiamento , Humanos , Indústrias/estatística & dados numéricos , Licenciamento/economia , Médicas/estatística & dados numéricos , Radio-Oncologistas/estatística & dados numéricos , Encaminhamento e Consulta/economia , Apoio à Pesquisa como Assunto/economia , Estudos Retrospectivos , Distribuição por Sexo , Estados Unidos
17.
Urology ; 126: 89-95, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30580007

RESUMO

OBJECTIVE: To determine the cost-effectiveness of using the Oncotype DX Genomic Prostate Score (GPS), a 17-gene expression assay that can be used to inform decisions regarding active surveillance (AS) vs immediate treatment. METHODS: We developed a Markov model simulating 20-year outcomes for 65-year-old men with very low-, low-, or favorable intermediate-risk prostate cancer undergoing AS vs immediate treatment using GPS vs no testing. Utilities, costs, and probabilities were extracted from the literature and National Medicare Fee Schedules to determine incremental cost-effectiveness ratios (ICER) from a payer perspective. RESULTS: In the overall cohort, the ICER of GPS-guided therapy was $31,394 per quality-adjusted life-year (QALY). When stratified by risk group, the ICER was $25,343 per QALY in very low-risk, $28,911 per QALY in low-risk, and $39,695 per QALY in favorable intermediate-risk patients. On sensitivity analysis, findings were robust against a willingness-to-pay of $100,000 per QALY to variations in key model parameters, including the cost of annual management of AS, probability of exiting AS to treatment, cost of treatment, and probability of biochemical failure post-treatment. However, the cost-effectiveness was sensitive to small differences in the utility of AS and the utility of no evidence of disease post-treatment states. CONCLUSION: The use of the GPS was cost-effective in guiding treatment decisions regarding AS vs immediate treatment. The cost-effectiveness was sensitive to small differences in the utilities of the AS and no evidence of disease post-treatment states, highlighting the importance of assessing patient preferences.


Assuntos
Tomada de Decisão Clínica , Análise Custo-Benefício , Regulação Neoplásica da Expressão Gênica , Genômica/economia , Neoplasias da Próstata/genética , Neoplasias da Próstata/terapia , Idoso , Humanos , Masculino , Cadeias de Markov , Estadiamento de Neoplasias , Neoplasias da Próstata/classificação , Neoplasias da Próstata/patologia
18.
Int J Radiat Oncol Biol Phys ; 102(1): 44-52, 2018 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-30102201

RESUMO

PURPOSE: To improve assessment of symptomatic toxicity in cancer clinical trials and complement clinician-based toxicity reporting, the US National Cancer Institute developed a measurement system called the Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE). The objective of this study was to examine the content validity of PRO-CTCAE in patients undergoing radiation therapy and to establish anatomic site-specific item sets for implementation in cancer research. METHODS AND MATERIALS: Patients receiving radiation to the brain, head and neck, breast, thorax, abdomen, or pelvis were recruited during the final week of radiation. Participants described side effects qualitatively and completed anatomic site-specific checklists indicating the presence or absence of symptomatic toxicities drawn from the PRO-CTCAE library. Items endorsed by ≥20% of participants were selected for inclusion. Symptomatic toxicities described qualitatively were content analyzed and summarized. Symptomatic toxicities not reflected in the PRO-CTCAE item library were tabulated. RESULTS: We conducted 389 interviews of patients receiving radiation to the brain (n = 46), head and neck (n = 69), breast (n = 134), thorax (n = 30), abdomen (n = 27), female pelvis (n = 36), or male pelvis (n = 47). Median age was 62 years; 62% were female. The 53 solicited PRO-CTCAE symptoms reflected all reported radiation-induced toxicities with the exception of phlegm/mucus production and mouth/throat pain with swallowing in patients receiving head and neck radiation, eye dryness/irritation in patients undergoing brain radiation, and obstructive urinary symptoms in men receiving pelvic radiation. The PRO-CTCAE items "skin burns" and "pain" require greater specificity to adequately reflect toxicities experienced during radiation. CONCLUSIONS: PRO-CTCAE demonstrates strong content validity as a measure of symptomatic toxicities in patients receiving radiation. These results provide empirical support for the definition of site-specific PRO-CTCAE item sets to assess the symptomatic toxicities of radiation therapy. The site-specific PRO-CTCAE item sets developed herein are currently being deployed in our department via an electronic platform to capture treatment-related toxicity.


Assuntos
Neoplasias/radioterapia , Medidas de Resultados Relatados pelo Paciente , Radioterapia/efeitos adversos , Humanos , Entrevistas como Assunto , Reprodutibilidade dos Testes
19.
Int J Radiat Oncol Biol Phys ; 97(3): 450-461, 2017 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-28011046

RESUMO

PURPOSE: Leaders in the oncology community are sounding a clarion call to promote "value" in cancer care decisions. Value in cancer care considers the clinical effectiveness, along with the costs, when selecting a treatment. To discuss possible solutions to the current obstacles to achieving value in the use of advanced technologies in oncology, the National Cancer Policy Forum of the National Academies of Sciences, Engineering, and Medicine held a workshop, "Appropriate Use of Advanced Technologies for Radiation Therapy and Surgery in Oncology" in July 2015. The present report summarizes the discussions related to radiation oncology. METHODS AND MATERIALS: The workshop convened stakeholders, including oncologists, researchers, payers, policymakers, and patients. Speakers presented on key themes, including the rationale for a value discussion on advanced technology use in radiation oncology, the generation of scientific evidence for value of advanced radiation technologies, the effect of both scientific evidence and "marketplace" (or economic) factors on the adoption of technologies, and newer approaches to improving value in the practice of radiation oncology. The presentations were followed by a panel discussion with dialogue among the stakeholders. RESULTS: Challenges to generating evidence for the value of advanced technologies include obtaining contemporary, prospective, randomized, and representative comparative effectiveness data. Proposed solutions include the use of prospective registry data; integrating radiation oncology treatment, outcomes, and quality benchmark data; and encouraging insurance coverage with evidence development. Challenges to improving value in practice include the slow adoption of higher value and the de-adoption of lower value treatments. The proposed solutions focused on engaging stakeholders in iterative, collaborative, and evidence-based efforts to define value and promote change in radiation oncology practice. Recent examples of ongoing or successful responses to the discussed challenges were provided. CONCLUSIONS: Discussions of "value" have increased as a priority in the radiation oncology community. Practitioners in the radiation oncology community can play a critical role in promoting a value-oriented framework to approach radiation oncology treatment.


Assuntos
Neoplasias/radioterapia , Radioterapia (Especialidade)/normas , Custos e Análise de Custo , Tomada de Decisões , Difusão de Inovações , Humanos , National Academies of Science, Engineering, and Medicine, U.S., Health and Medicine Division , Avaliação de Programas e Projetos de Saúde , Terapia com Prótons/economia , Terapia com Prótons/estatística & dados numéricos , Terapia com Prótons/tendências , Radioterapia (Especialidade)/economia , Radioterapia (Especialidade)/instrumentação , Radioterapia/economia , Radioterapia/instrumentação , Radioterapia/normas , Radioterapia de Intensidade Modulada/economia , Radioterapia de Intensidade Modulada/estatística & dados numéricos , Radioterapia de Intensidade Modulada/tendências , Pesquisadores , Tecnologia Radiológica/economia , Tecnologia Radiológica/normas , Estados Unidos
20.
Med Phys ; 43(8): 4514, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27487868

RESUMO

PURPOSE: Magnetic resonance imaging (MRI) guidance in radiation therapy brings real-time imaging and adaptive planning into the treatment vault where it can account for interfraction and intrafraction movement of soft tissue. The only commercially available MRI-guided radiation therapy device is a three-head (60)Co and MRI system with an integrated treatment planning system (TPS). Couch attenuation of the beam of up to 20% is well modeled in the TPS. Variations in the patient's day-to-day position introduce discrepancies in the actual couch attenuation as modeled in the treatment plan. For this reason, the authors' institution avoids plans with beams that pass through or near the couch edges. This study investigates the effects of differential beam attenuation by the couch due to couch shifts in order to determine whether couch edge avoidance restrictions can be lifted. Couch shifts were simulated using a Monte Carlo treatment planning system and ion chamber measurements performed for validation. METHODS: A total of 27 plans from 23 patients were investigated. Couch shifts of 1 and 2 cm were introduced in combinations of lateral and vertical directions to simulate patient position variations giving 16 shifted plans per reference plan. The 1 and 2 cm shifts were based on shifts recorded in 320 treatment fractions. RESULTS: Following TG176 recommendations for measurement methods, couch attenuation measurements agreed with TPS modeled attenuation to within 2.1%. Planning target volume D95 changed less than 1% for 1 and 2 cm couch shifts in only the x-direction and less than 3% for all directions. CONCLUSIONS: Dosimetry of all plans tested was robust to couch shifts up to ±2 cm. In general, couch shifts resulted in clinically insignificant dosimetric deviations. It is conceivable that in certain cases with large systematic couch shifts and plans that are particularly sensitive to shifts, dosimetric changes might rise to a clinically significant level.


Assuntos
Radioisótopos de Cobalto/uso terapêutico , Imageamento por Ressonância Magnética/instrumentação , Posicionamento do Paciente/instrumentação , Equipamentos e Provisões para Radiação , Planejamento da Radioterapia Assistida por Computador/instrumentação , Radioterapia Guiada por Imagem/instrumentação , Simulação por Computador , Humanos , Imageamento por Ressonância Magnética/métodos , Modelos Teóricos , Método de Monte Carlo , Neoplasias/diagnóstico por imagem , Neoplasias/radioterapia , Posicionamento do Paciente/métodos , Radiometria , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Guiada por Imagem/métodos
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