RESUMEN
This special report aims to inform the medical community about the many challenges involved in managing radiation exposure in a way that maximizes the benefit-risk ratio. The report discusses the state of current knowledge and key questions in regard to sources of medical imaging radiation exposure, radiation risk estimation, dose reduction strategies, and regulatory options.
Asunto(s)
Diagnóstico por Imagen/efectos adversos , Traumatismos por Radiación/prevención & control , Fluoroscopía/efectos adversos , Humanos , Neoplasias Inducidas por Radiación/prevención & control , Dosis de Radiación , Protección Radiológica , Radiografía Intervencional/efectos adversos , Medición de Riesgo , Factores de Riesgo , Factores SexualesRESUMEN
Medical products (devices, drugs, or biologics) contain information in their labeling regarding the manner in which the manufacturer has determined that the products can be used in a safe and effective manner. The Food and Drug Administration (FDA) approves medical products for use for these specific indications which are part of the medical product's labeling. When medical products are used in a manner not specified in the labeling, it is commonly referred to as off-label use. The practice of medicine allows for this off-label use to treat individual patients, but the ethical and legal implications for such unapproved use can be confusing. Although the responsibility and, ultimately, the liability for off-label use often rests with the prescribing physician, medical physicists and others are also responsible for the safe and proper use of the medical products. When these products are used for purposes other than which they were approved, it is important for medical physicists to understand their responsibilities. In the United States, medical products can only be marketed if officially cleared, approved, or licensed by the FDA; they can be used if they are not subject to or specifically exempt from FDA regulations, or if they are being used in research with the appropriate regulatory safeguards. Medical devices are either cleared or approved by FDA's Center for Devices and Radiological Health. Drugs are approved by FDA's Center for Drug Evaluation and Research, and biological products such as vaccines or blood are licensed under a biologics license agreement by FDA's Center for Biologics Evaluation and Research. For the purpose of this report, the process by which the FDA eventually clears, approves, or licenses such products for marketing in the United States will be referred to as approval. This report summarizes the various ways medical products, primarily medical devices, can legally be brought to market in the United States, and includes a discussion of the approval process, along with manufacturers' responsibilities, labeling, marketing and promotion, and off-label use. This is an educational and descriptive report and does not contain prescriptive recommendations. This report addresses the role of the medical physicist in clinical situations involving off-label use. Case studies in radiation therapy are presented. Any mention of commercial products is for identification only; it does not imply recommendations or endorsements of any of the authors or the AAPM. The full report, containing extensive background on off-label use with several appendices, is available on the AAPM website (http://www.aapm.org/pubs/reports/).
Asunto(s)
Comités Consultivos , Equipos y Suministros , Uso Fuera de lo Indicado/legislación & jurisprudencia , Radioterapia/instrumentación , Sociedades Científicas , United States Food and Drug Administration/legislación & jurisprudencia , Braquiterapia/instrumentación , Humanos , Responsabilidad Legal , Microesferas , Neoplasias/terapia , Uso Fuera de lo Indicado/estadística & datos numéricos , Mecanismo de Reembolso/legislación & jurisprudencia , Estados UnidosRESUMEN
This study was undertaken to compare the entrance surface dose (ESD) and image quality of adult chest and abdominal X-ray examinations conducted at general practitioner (GP) clinics, and public and private hospitals in Malaysia. The surveyed facilities were randomly selected within a given category (28 GP clinics, 20 public hospitals and 15 private hospitals). Only departmental X-ray units were involved in the survey. Chest examinations were done at all facilities, while only hospitals performed abdominal examinations. This study used the x-ray attenuation phantoms and protocols developed for the Nationwide Evaluation of X-ray Trends (NEXT) survey program in the United States. The ESD was calculated from measurements of exposure and clinical geometry. An image quality test tool was used to evaluate the low-contrast detectability and high-contrast detail performance under typical clinical conditions. The median ESD value for the adult chest X-ray examination was the highest (0.25 mGy) at GP clinics, followed by private hospitals (0.22 mGy) and public hospitals (0.17 mGy). The median ESD for the adult abdominal X-ray examination at public hospitals (3.35 mGy) was higher than that for private hospitals (2.81 mGy). Results of image quality assessment for the chest X-ray examination show that all facility types have a similar median spatial resolution and low-contrast detectability. For the abdominal X-ray examination, public hospitals have a similar median spatial resolution but larger low-contrast detectability compared with private hospitals. The results of this survey clearly show that there is room for further improvement in performing chest and abdominal X-ray examinations in Malaysia.
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Carga Corporal (Radioterapia) , Medicina Familiar y Comunitaria/estadística & datos numéricos , Hospitales Privados/estadística & datos numéricos , Hospitales Públicos/estadística & datos numéricos , Interpretación de Imagen Asistida por Computador , Radiografía Abdominal/estadística & datos numéricos , Radiografía Torácica/estadística & datos numéricos , Adulto , Humanos , Malasia/epidemiología , Efectividad Biológica RelativaRESUMEN
In the United States, human research involving radioactive drugs must be conducted under a Food and Drug Administration (FDA) investigational new drug (IND) application, unless specifically exempt from IND requirements, or under the direct oversight of a Radioactive Drug Research Committee (RDRC) as long as certain conditions are met. Research overseen by RDRCs is considered basic science research when its purpose is to advance scientific knowledge and not to determine a radioactive drug's safety and effectiveness as a therapeutic, diagnostic, or preventive medical product in humans. We retrospectively reviewed and analyzed available study data from annual reports submitted to the FDA dating back to 1976. In 1976, there were 18 studies involving 531 subjects compared with 2003, when there were 284 RDRC studies involving 2,797 subjects. In 1976, RDRC subjects were imaged 5% of the time using positron-emitting nuclides and 77% of the time with conventional gamma-emitting nuclides. In 2003, this was reversed with 77% using positron emitters and 5% using conventional gamma-emitters. In 1976, pediatric studies comprised 7.3% of all RDRC subjects; today pediatric RDRC studies are rarely conducted. Today the RDRC is used primarily by large medical research institutions. Although the program has a very good safety record, RDRC's 30-y-old regulations need to be revised to be consistent with current scientific knowledge and health policy.
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Drogas en Investigación/normas , Radiofármacos/normas , Radioterapia/normas , Investigación Biomédica/normas , Ensayos Clínicos como Asunto , Aprobación de Drogas , Evaluación de Medicamentos , Experimentación Humana , Humanos , Comité Farmacéutico y Terapéutico , Tomografía de Emisión de Positrones/normas , Estudios Retrospectivos , Factores de Tiempo , Estados Unidos , United States Food and Drug AdministrationRESUMEN
Reference values (RVs) are recommended by the American Association of Physicists in Medicine for four radiographic projections, computed tomography, fluoroscopy, and dental radiography. RVs are used to compare radiation doses from individual pieces of radiographic equipment with doses from similar equipment assessed in national surveys. RVs recommended by the American Association of Physicists in Medicine have been developed from the Nationwide Evaluation of X-ray Trends survey performed by the state radiation protection agencies with the cooperation and support of the U.S. Food and Drug Administration, the Conference of Radiation Control Program Directors, and the American College of Radiology. The RVs selected by the American Association of Physicists in Medicine represent, approximately, the 80th percentile of the survey distributions. Consequently, equipment exceeding the RVs is using higher radiation doses than is 80% of the equipment in the surveys. Radiation doses for specific projections, with standard phantoms, should be measured annually, as recommended by the American College of Radiology. When the RVs are exceeded, the medical physicist should investigate the cause and determine, in cooperation with the responsible radiologist, whether these doses are justified or the imaging system should be optimized to reduce patient radiation doses. RVs are a useful tool for comparing patient radiation doses at institutions throughout the United States and for providing information about radiographic equipment performance.
Asunto(s)
Fluoroscopía/normas , Radiografía Dental/normas , Radiografía/normas , Radiometría/normas , Tomografía Computarizada por Rayos X/normas , Seguridad de Equipos , Fluoroscopía/instrumentación , Humanos , Fantasmas de Imagen , Dosis de Radiación , Monitoreo de Radiación/normas , Radiografía/instrumentación , Radiografía Dental/instrumentación , Valores de Referencia , Tomografía Computarizada por Rayos X/instrumentación , Estados UnidosRESUMEN
Results of the 1995 Nationwide Evaluation of X-ray Trends (NEXT) survey of facilities that perform diagnostic radiographic examinations of the abdomen and lumbosacral spine were compared with those of previous NEXT surveys conducted in 1987 and 1989. A clinically validated radiographic phantom was used in the 1995 survey to capture data about radiation exposure and image quality. Additional data were obtained regarding clinical techniques, facility workloads, x-ray beam quality, film processing quality, and darkroom fog. Mean skin-entrance air kerma for the abdomen examination dropped from 3.2 mGy (in 1987) to 2.8 mGy at hospitals and from 3.4 mGy (in 1989) to 3.0 mGy at nonhospital facilities. Mean skin-entrance air kerma also decreased for the lumbosacral spine examination from 3.7 mGy (in 1987) to 3.3 mGy at hospitals and from 3.8 mGy (in 1989) to 3.2 mGy at nonhospital facilities. The quality of film processing improved, although 58 (18.3%) of 317 surveyed facilities did not meet the Mammography Quality Standards Act standard for film processing quality, compared with 185 (5.9%) of 3,120 mammography facilities inspected in 1995. Finally, 181 (58.0%) of 312 surveyed facilities had darkroom fog levels greater than the Mammography Quality Standards Act standard, compared with 1,426 (16.6%) of 8,605 mammography facilities inspected in 1995.