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1.
J Oncol Pharm Pract ; 30(1): 127-141, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37122190

RESUMEN

PURPOSE: Oncology care continues to evolve at a rapid pace including provision of infusion-based care. There is currently a lack of robust metrics around oncology infusion centers and pharmacy practice. The workgroup completed a nationwide survey to learn about oncology-based infusion pharmacy services offered. The objective was to highlight consistent, measureable oncology-based infusion pharmacy metrics that will provide a foundation to describe overall productivity including emphasis on high patient-safety standards. METHODS: A nationwide survey was developed via a workgroup within the Vizient Pharmacy Cancer Care Group beginning in April 2019 and conducted electronically via the Vizient Pharmacy Network from September to November 2020. The survey was designed to capture a number of key metrics related to oncology-based infusion pharmacy services. RESULTS: Forty-one sites responded to the survey. Responses highlighted hours of operation (median = 11.5), number of infusion chairs (median = 45). Staffing metrics included 7.1 pharmacist full-time equivalent (FTE) and 7.6 technician FTE per week. 80.5% of sites had cleanrooms and 95.1% reported both hazardous and nonhazardous compounding hoods. 68.3% of sites reported using intravenous (IV) technology, 50.0% measured turnaround time, and 31.4% prepared treatment medications in advance. CONCLUSION: There was variability among oncology infusion pharmacy practices in regard to survey responses among sites. The survey results highlight the need for standardization of established productivity metrics across oncology infusion pharmacies in order to improve efficiency and contain costs in the changing oncology landscape. The survey provides insight into oncology infusion pharmacy practices nationwide and provides information for pharmacy leaders to help guide their practices.


Asunto(s)
Servicios Farmacéuticos , Farmacias , Farmacia , Humanos , Oncología Médica , Farmacéuticos , Encuestas y Cuestionarios , Bombas de Infusión
2.
Bone Marrow Transplant ; 50(5): 652-7, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-25665041

RESUMEN

Obesity continues to be an increasing global health issue contributing to the complexity of chemotherapy dosing in the field of SCT. Investigation into the optimal dosing weight used to calculate chemotherapy doses in obese patients undergoing SCT is limited and inconclusive. Our single-center, retrospective study compared safety and efficacy outcomes by body mass index (BMI) for 476 adult lymphoma patients who underwent auto-SCT with a myeloablative chemotherapeutic regimen of BU, CY and etoposide dosed using adjusted body weight. Three weight groups categorized based on BMI were defined: normal/underweight ⩽24.9 kg/m(2), overweight 25-29.9 kg/m(2) and obese ⩾30 kg/m(2). Severity of mucositis, incidence of secondary malignancy, incidence of bacteremia and median hospital length of stay did not differ among the groups. The median times to absolute neutrophil count and platelet recovery were 10 days (P=0.75) and 14 days (P=0.17), respectively. Obese patients had a lower 100-day mortality compared with other weight groups, although this did not translate into an OS benefit. OS and disease relapse were similar among the groups. Our study demonstrates that use of adjusted body weight to calculate chemotherapy doses does not negatively have an impact on outcomes in obese patients undergoing auto-SCT with BU, CY and etoposide.


Asunto(s)
Peso Corporal , Linfoma/terapia , Agonistas Mieloablativos/administración & dosificación , Trasplante de Células Madre , Acondicionamiento Pretrasplante/métodos , Adulto , Anciano , Autoinjertos , Supervivencia sin Enfermedad , Femenino , Humanos , Linfoma/mortalidad , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Tasa de Supervivencia
3.
BMJ Case Rep ; 20152015 Jan 05.
Artículo en Inglés | MEDLINE | ID: mdl-25564582

RESUMEN

Kikuchi-Fujimoto disease (KFD) or histiocytic necrotising lymphadenitis is a rare entity, occurring most commonly in young Asian adults. KFD is characterised by fever with tender lymph node enlargement. The cervical group of lymph nodes is most commonly involved, and the diagnosis is conclusively made by lymph node biopsy and histopathology. KFD is a self-limiting condition, which usually resolves over 1-4 months. Symptomatic treatment with antipyretics and/or non-steroidal anti-inflammatory drugs is recommended. Here we describe an uncommon presentation of KFD in a young woman in which only the axillary lymph nodes were enlarged.


Asunto(s)
Linfadenitis Necrotizante Histiocítica/patología , Ganglios Linfáticos/patología , Adulto , Axila , Biopsia , Escalofríos/etiología , Femenino , Fiebre/etiología , Linfadenitis Necrotizante Histiocítica/complicaciones , Linfadenitis Necrotizante Histiocítica/diagnóstico , Humanos
4.
Undersea Hyperb Med ; 40(6): 499-504, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24377192

RESUMEN

INTRODUCTION: Hyperbaric oxygen (HBO2) therapy has been used to promote viability of compromised flaps despite a paucity of supportive clinical evidence. This study provides an in-depth characterization of hyperbaric medicine to promote flap survival and identifies treatment variables associated with positive clinical outcomes. METHODS: A retrospective review was conducted of patients who received HBO2 therapy for a failing or threatened post-reconstructive flap from 5/30/2008 through 4/30/2012. Medical records were reviewed to collect patient characteristics, hyperbaric oxygen therapy details, and clinical outcomes. Descriptive and comparative statistics were utilized. RESULTS: Ninety-one patients underwent HBO2 therapy during this time period, with 15 patients meeting the selection criteria. Flap survival was achieved in 11 patients (73.3%). Of those successfully treated, four (36.4%) healed completely, and seven (63.6%) demonstrated marked improvement. Patients who were treated successfully demonstrated an average improvement in flap area of 68.3%. Variables significantly associated with a favorable treatment outcome included a high percentage of treatment completion (p = 0.022) and high pretreatment transcutaneous oxygen measurements (p = 0.05). Smoking was a negative factor (p = 0.011). CONCLUSION: This study provides clinical data characterizing and supporting the application of hyperbaric medicine to aid in the viability of compromised flaps.


Asunto(s)
Supervivencia de Injerto , Oxigenoterapia Hiperbárica/métodos , Colgajos Quirúrgicos/fisiología , Adolescente , Adulto , Anciano , Femenino , Humanos , Oxigenoterapia Hiperbárica/efectos adversos , Masculino , Persona de Mediana Edad , Cooperación del Paciente , Estudios Retrospectivos , Factores de Riesgo , Fumar/efectos adversos , Adulto Joven
5.
Can Vet J ; 53(4): 378-82, 2012 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23024382

RESUMEN

Visualization of colonic mesenteric vasculature during transabdominal ultrasonographic examination of horses with colic can be a predictor of right dorsal displacement of the large colon or 180° large colon volvulus, or both. Medical records of 82 horses having had surgical treatment of colic and having received a transabdominal ultrasonographic examination on admission were reviewed. Colonic mesenteric vessels were sonographically identified coursing laterally on the right side of the abdomen in 24 of the 82 cases. Horses with colonic vessels identified on ultrasound were 32.5 times more likely to be diagnosed at surgery with either large colon right dorsal displacement or 180° large colon volvulus than those in which vessels were not seen (P < 0.001). Visualization of colonic mesenteric vessels on ultrasound provided a sensitivity of 67.7%, specificity of 97.9%, positive predictive value of 95.8%, and negative predictive value of 81% for large colon right dorsal displacement or 180° large colon volvulus, or both.


Asunto(s)
Enfermedades del Colon/veterinaria , Enfermedades de los Caballos/diagnóstico por imagen , Vólvulo Intestinal/veterinaria , Mesenterio/irrigación sanguínea , Mesenterio/diagnóstico por imagen , Animales , Cólico/diagnóstico , Cólico/diagnóstico por imagen , Cólico/veterinaria , Enfermedades del Colon/diagnóstico , Enfermedades del Colon/diagnóstico por imagen , Diagnóstico Diferencial , Femenino , Enfermedades de los Caballos/diagnóstico , Caballos , Vólvulo Intestinal/diagnóstico por imagen , Masculino , Valor Predictivo de las Pruebas , Ultrasonografía
6.
Compend Contin Educ Vet ; 34(10): E1-5, 2012 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-23532760

RESUMEN

A 14-year-old Hanoverian gelding was evaluated after a 10-week history of occasional straining during urination and dark red urine production after exercise. Physical examination findings were within normal limits. After 2 weeks of clinical signs, ultrasonography had found no abnormalities in the kidneys or bladder. A freely voided urine sample revealed an elevated protein concentration (500 mg/dL; reference range: <100 mg/dL) and few red blood cells. Vitamin C supplementation was suggested to acidify the urine, as was provision of a salt block to encourage water intake.


Asunto(s)
Carcinoma de Células Escamosas/veterinaria , Enfermedades de los Caballos/diagnóstico , Neoplasias de la Vejiga Urinaria/veterinaria , Animales , Carcinoma de Células Escamosas/diagnóstico , Carcinoma de Células Escamosas/cirugía , Resultado Fatal , Enfermedades de los Caballos/cirugía , Caballos , Masculino , Neoplasias de la Vejiga Urinaria/diagnóstico , Neoplasias de la Vejiga Urinaria/cirugía
9.
J Org Chem ; 75(4): 1155-61, 2010 Feb 19.
Artículo en Inglés | MEDLINE | ID: mdl-20102230

RESUMEN

A potent reversible inhibitor of the cysteine protease cathepsin-S was prepared on large scale using a convergent synthetic route, free of chromatography and cryogenics. Late-stage peptide coupling of a chiral urea acid fragment with a functionalized aminonitrile was employed to prepare the target, using 2-hydroxypyridine as a robust, nonexplosive replacement for HOBT. The two key intermediates were prepared using a modified Strecker reaction for the aminonitrile and a phosphonation-olefination-rhodium-catalyzed asymmetric hydrogenation sequence for the urea. A palladium-catalyzed vinyl transfer coupled with a Claisen reaction was used to produce the aldehyde required for the side chain. Key scale up issues, safety calorimetry, and optimization of all steps for multikilogram production are discussed.


Asunto(s)
Alquenos/síntesis química , Catepsinas/antagonistas & inhibidores , Catepsinas/química , Inhibidores Enzimáticos/síntesis química , Urea/síntesis química , Compuestos de Vinilo/síntesis química , Alquenos/química , Calorimetría/métodos , Catálisis , Ciclización , Inhibidores Enzimáticos/farmacología , Indicadores y Reactivos/química , Modelos Moleculares , Estructura Molecular , Paladio/química , Rodio/química , Estereoisomerismo , Urea/química , Compuestos de Vinilo/química
10.
Med Phys ; 34(2): 464-70, 2007 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-17388162

RESUMEN

Intensity modulated arc therapy (IMAT) is an intensity modulated radiation therapy delivery technique originally proposed as an alternative to tomotherapy. IMAT uses a series of overlapping arcs to deliver optimized intensity patterns from each beam direction. The full potential of IMAT has gone largely unrealized due in part to a lack of robust and commercially available inverse planning tools. To address this, we have implemented an IMAT arc-sequencing algorithm that translates optimized intensity maps into deliverable IMAT plans. The sequencing algorithm uses simulated annealing to simultaneously optimize the aperture shapes and weights throughout each arc. The sequencer enforces the delivery constraints while minimizing the discrepancies between the optimized and sequenced intensity maps. The performance of the algorithm has been tested for ten patient cases (3 prostate, 3 brain, 2 head-and-neck, 1 lung, and 1 pancreas). Seven coplanar IMAT plans were created using an average of 4.6 arcs and 685 monitor units. Additionally, three noncoplanar plans were created using an average of 16 arcs and 498 monitor units. The results demonstrate that the arc sequencer can provide efficient and highly conformal IMAT plans. An average sequencing time of approximately 20 min was observed.


Asunto(s)
Algoritmos , Modelos Biológicos , Radiometría/métodos , Planificación de la Radioterapia Asistida por Computador/métodos , Radioterapia Asistida por Computador/métodos , Radioterapia Conformacional/métodos , Simulación por Computador , Humanos , Dosificación Radioterapéutica , Dispersión de Radiación
11.
Med Phys ; 34(1): 307-14, 2007 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-17278516

RESUMEN

Using direct aperture optimization, we have developed an inverse planning approach that is capable of producing efficient intensity modulated radiotherapy (IMRT) treatment plans that can be delivered without a multileaf collimator. This "jaws-only" approach to IMRT uses a series of rectangular field shapes to achieve a high degree of intensity modulation from each beam direction. Direct aperture optimization is used to directly optimize the jaw positions and the relative weights assigned to each aperture. Because the constraints imposed by the jaws are incorporated into the optimization, the need for leaf sequencing is eliminated. Results are shown for five patient cases covering three treatment sites: pancreas, breast, and prostate. For these cases, between 15 and 20 jaws-only apertures were required per beam direction in order to obtain conformal IMRT treatment plans. Each plan was delivered to a phantom, and absolute and relative dose measurements were recorded. The typical treatment time to deliver these plans was 18 min. The jaws-only approach provides an additional IMRT delivery option for clinics without a multileaf collimator.


Asunto(s)
Algoritmos , Modelos Biológicos , Neoplasias/radioterapia , Radiometría/métodos , Planificación de la Radioterapia Asistida por Computador/métodos , Radioterapia Conformacional/métodos , Simulación por Computador , Humanos , Especificidad de Órganos , Dosificación Radioterapéutica , Efectividad Biológica Relativa
12.
Am J Vet Res ; 67(10): 1687-95, 2006 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-17014317

RESUMEN

OBJECTIVE: To evaluate the pharmacokinetic-pharmacodynamic parameters of enrofloxacin and a low dose of amikacin administered via regional IV limb perfusion (RILP) in standing horses. ANIMALS: 14 adult horses. PROCEDURES: Standing horses (7 horses/group) received either enrofloxacin (1.5 mg/kg) or amikacin (250 mg) via RILP (involving tourniquet application) in 1 forelimb. Samples of interstitial fluid (collected via implanted capillary ultrafiltration devices) from the bone marrow (BMIF) of the third metacarpal bone and overlying subcutaneous tissues (STIF), blood, and synovial fluid of the radiocarpal joint were collected prior to (time 0) and at intervals after tourniquet release for determination of drug concentrations. For pharmacokinetic-pharmacodynamic analyses, minimum inhibitory concentrations (MICs) of 16 microg/mL (amikacin) and 0.5 microg/mL (enrofloxacin) were applied. RESULTS: After RILP with enrofloxacin, 3 horses developed vasculitis. The highest synovial fluid concentrations of enrofloxacin and amikacin were detected at time 0; median values (range) were 13.22 microg/mL (0.254 to 167.9 microg/mL) and 26.2 microg/mL (5.78 to 50.0 microg/mL), respectively. Enrofloxacin concentrations exceeded MIC for approximately 24 hours in STIF and synovial fluid and for 36 hours in BMIF. After perfusion of amikacin, concentrations greater than the MIC were not detected in any samples. Effective therapeutic concentrations of enrofloxacin were attained in all samples. CONCLUSIONS AND CLINICAL RELEVANCE: In horses with orthopedic infections, RILP of enrofloxacin (1.5 mg/kg) should be considered as a treatment option. However, care must be taken during administration. A dose of amikacin > 250 mg is recommended to attain effective tissue concentrations via RILP in standing horses.


Asunto(s)
Amicacina/farmacocinética , Antibacterianos/farmacocinética , Fluoroquinolonas/farmacocinética , Caballos/metabolismo , Amicacina/administración & dosificación , Animales , Antibacterianos/administración & dosificación , Área Bajo la Curva , Médula Ósea/metabolismo , Enrofloxacina , Miembro Anterior , Pruebas de Sensibilidad Microbiana , Distribución Aleatoria , Líquido Sinovial/metabolismo , Distribución Tisular
13.
Vet Surg ; 34(6): 565-70, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-16343143

RESUMEN

OBJECTIVE: To test the failure strength and energy of 2 bioabsorbable implants applied to transected deep digital flexor tendons (DDFT) from adult horses. STUDY DESIGN: Ex vivo biomechanical experiment. SAMPLE POPULATION: Twelve pairs of deep digital flexor tendons harvested from the forelimbs of fresh equine cadavers. METHODS: Poly-L-lactic acid tendon plates were custom manufactured for application to the cylindrical surface of an adult equine deep digital flexor tendon. Twelve pairs of DDFTs were transected 2 cm distal to the insertion of the distal check ligament of the deep digital flexor tendon. One tendon of each pair was randomly selected for repair with a biodegradable plate or a 3-loop pulley method. Size 2 polydioxanone suture was used in both repairs. Repairs were tested in tension to failure, with peak force (PF) and total energy (TE) at repair failure recorded in Newtons (N) and Joules (J), respectively. A paired t-test was used for statistical evaluation with a significant level set at P< or = .05. RESULTS: Mean+/-SD PF for failure of plated tendons (1507.08+/-184.34 N) was significantly greater than for sutured tendons (460.86+/-60.93 N). TE was also significantly greater for failure of plated tendons versus sutured tendons. CONCLUSIONS: Plate fixation of transected cadaver DDFTs appear to have superior immediate failure strength than 3-loop pulley repairs. CLINICAL RELEVANCE: Whereas in vivo testing is required, a bioabsorbable tendon plate may provide initial increased strength to support tendon healing and decrease external coaptation requirements.


Asunto(s)
Implantes Absorbibles/veterinaria , Caballos , Técnicas de Sutura/veterinaria , Traumatismos de los Tendones , Traumatismos de los Tendones/veterinaria , Implantes Absorbibles/normas , Animales , Fenómenos Biomecánicos , Cadáver , Miembro Anterior , Caballos/lesiones , Caballos/cirugía , Técnicas de Sutura/normas , Suturas/veterinaria , Traumatismos de los Tendones/cirugía , Tendones/cirugía
14.
Phys Med Biol ; 50(23): 5653-63, 2005 Dec 07.
Artículo en Inglés | MEDLINE | ID: mdl-16306659

RESUMEN

We have examined the degree to which step-and-shoot IMRT treatment plans can be simplified (using a small number of apertures) without sacrificing the dosimetric quality of the plans. A key element of this study was the use of direct aperture optimization (DAO), an inverse planning technique where all of the multi-leaf collimator constraints are incorporated into the optimization. For seven cases (1 phantom, 1 prostate, 3 head-and-neck and 2 lung), DAO was used to perform a series of optimizations where the number of apertures per beam direction varied from 1 to 15. In this work, we attempt to provide general guidelines for how many apertures per beam direction are sufficient for various clinical cases using DAO. Analysis of the optimized treatment plans reveals that for most cases, only modest improvements in the objective function and the corresponding DVHs are seen beyond 5 apertures per beam direction. However, for more complex cases, some dosimetric gain can be achieved by increasing the number of apertures per beam direction beyond 5. Even in these cases, however, only modest improvements are observed beyond 9 apertures per beam direction. In our clinical experience, 38 out of the first 40 patients treated using IMRT plans produced using DAO were treated with 9 or fewer apertures per beam direction. The results indicate that many step-and-shoot IMRT treatment plans delivered today are more complex than necessary and can be simplified without sacrificing plan quality.


Asunto(s)
Aceleradores de Partículas/instrumentación , Radioterapia de Intensidad Modulada/instrumentación , Radioterapia de Intensidad Modulada/métodos , Algoritmos , Simulación por Computador , Humanos , Neoplasias Pulmonares/radioterapia , Masculino , Fantasmas de Imagen , Neoplasias de la Próstata/radioterapia , Radiometría , Dosificación Radioterapéutica , Planificación de la Radioterapia Asistida por Computador/métodos , Radioterapia Asistida por Computador , Programas Informáticos , Factores de Tiempo
15.
Vet Clin North Am Equine Pract ; 21(2): 511-35, viii, 2005 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-16051060

RESUMEN

Abdominal surgery in foals under 30 days old has become more common with improved neonatal care. Early recognition of a foal at risk and better nursing care have increased the survival rates of foals that require neonatal care. The success of improved neonatal care also has increased the need for accurate diagnosis and treatment of gastrointestinal, umbilical, and bladder disorders in these foals. This chapter focuses on the early and accurate diagnosis of specific disorders that require abdominal exploratory surgery and the specific treatment considerations and prognosis for these disorders.


Asunto(s)
Abdomen/cirugía , Animales Recién Nacidos/cirugía , Enfermedades Gastrointestinales/veterinaria , Enfermedades de los Caballos/cirugía , Animales , Enfermedades Gastrointestinales/cirugía , Caballos , Examen Físico/veterinaria , Pronóstico
16.
Anesth Analg ; 99(6): 1848-1853, 2004 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-15562085

RESUMEN

We compared postoperative recovery after desflurane (n = 25) versus sevoflurane (n = 25) anesthesia in morbidly obese adults (body mass index >/=35) who underwent gastrointestinal bypass surgery via an open laparotomy. After premedication with midazolam and metoclopramide 1 h before surgery, epidural catheter placement, induction of anesthesia with fentanyl and propofol, and tracheal intubation facilitated with succinylcholine, anesthesia was maintained with age-adjusted 1 minimum alveolar concentration (MAC) desflurane or sevoflurane. Fentanyl IV, morphine or local anesthetics epidurally, and vasoactive drugs as needed were used to maintain arterial blood pressure at +/-20% of baseline value and to keep bispectral index of the electroencephalogram values between 40 to 60 U. Although patients were anesthetized with desflurane for a longer time (261 +/- 50 min versus 234 +/- 37 min, mean +/- sd; P < 0.05, desflurane versus sevoflurane, respectively) and for more MAC-hours (4.2 +/- 0.9 h versus 3.7 +/- 0.8 h; P < 0.05), significantly earlier recovery of response to command and tracheal extubation occurred in patients given desflurane than in patients given sevoflurane. The modified Aldrete score was greater in desflurane-anesthetized patients on admission to the postanesthesia care unit (PACU) (P = 0.01) but not at discharge (P = 0.47). On admission to PACU, patients given desflurane had higher oxygen saturations (97.0% +/- 2.4%) than patients given sevoflurane (94.8% +/- 4.4%, P = 0.035). Overall, the incidence of postoperative nausea and vomiting and the use of antiemetics did not differ between the two anesthetic groups. We conclude that morbidly obese adult patients who underwent major abdominal surgery in a prospective, randomized study awoke significantly faster after desflurane than after sevoflurane anesthesia and the patients anesthetized with desflurane had higher oxygen saturation on entry to the PACU.


Asunto(s)
Anestésicos por Inhalación , Isoflurano/análogos & derivados , Éteres Metílicos , Obesidad Mórbida/complicaciones , Adulto , Periodo de Recuperación de la Anestesia , Desflurano , Electroencefalografía/efectos de los fármacos , Femenino , Derivación Gástrica , Hemodinámica/fisiología , Humanos , Laparotomía , Masculino , Persona de Mediana Edad , Oxígeno/sangre , Náusea y Vómito Posoperatorios/epidemiología , Estudios Prospectivos , Sevoflurano
17.
Med Phys ; 30(9): 2320-2, 2003 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-14528953

RESUMEN

We have designed a toolbox that provides an environment for testing radiotherapy optimization techniques, objective functions, and constraints. A set of three-dimensional (3D) pencil beam dose distributions have been computed for a cylindrical phantom. The 6 MV pencil beams were computed using a superposition-based dose engine commissioned for an Elekta SL20 linear accelerator. Due to the cylindrical symmetry of the phantom, the pencil beam dose distributions for any arbitrary beam angle can be determined by simply rotating the pencil beam data sets. Thus, the full accuracy is maintained without the need for additional dose calculations or large data storage requirements. In addition to the pencil beam data sets, tools are included for (1) rotating the pencil beams, (2) calculating the beam's eye view, (3) drawing structures, (4) writing the pencil beam dose data out to the optimizer, and (5) visualizing the optimized results. The pencil beam data sets and the corresponding tools are available for download at http://medschool.umaryland.edu/departments/radiationoncology/pencilbeam/. With this toolbox, researchers will have the ability to rapidly test new optimization techniques and formulations for intensity modulated radiation therapy and 3D conformal radiotherapy.


Asunto(s)
Algoritmos , Gráficos por Computador , Radiometría/métodos , Dosificación Radioterapéutica , Planificación de la Radioterapia Asistida por Computador/métodos , Radioterapia Conformacional/métodos , Programas Informáticos , Interfaz Usuario-Computador , Bases de Datos Factuales , Control de Calidad
18.
Phys Med Biol ; 48(8): 1075-89, 2003 Apr 21.
Artículo en Inglés | MEDLINE | ID: mdl-12741503

RESUMEN

Intensity-modulated arc therapy (IMAT) is a radiation therapy delivery technique that combines gantry rotation with dynamic multi-leaf collimation (MLC). With IMAT, the benefits of rotational IMRT can be realized using a conventional linear accelerator and a conventional MLC. Thus far, the advantages of IMAT have gone largely unrealized due to the lack of robust automated planning tools capable of producing efficient IMAT treatment plans. This work describes an inverse treatment planning algorithm, called 'direct aperture optimization' (DAO) that can be used to generate inverse treatment plans for IMAT. In contrast to traditional inverse planning techniques where the relative weights of a series of pencil beams are optimized, DAO optimizes the leaf positions and weights of the apertures in the plan. This technique allows any delivery constraints to be enforced during the optimization, eliminating the need for a leaf-sequencing step. It is this feature that enables DAO to easily create inverse plans for IMAT. To illustrate the feasibility of DAO applied to IMAT, several cases are presented, including a cylindrical phantom, a head and neck patient and a prostate patient.


Asunto(s)
Algoritmos , Neoplasias de Cabeza y Cuello/radioterapia , Neoplasias de la Próstata/radioterapia , Radiometría/métodos , Planificación de la Radioterapia Asistida por Computador/métodos , Radioterapia Conformacional/instrumentación , Radioterapia Conformacional/métodos , Simulación por Computador , Estudios de Factibilidad , Humanos , Masculino , Fantasmas de Imagen , Control de Calidad , Dosificación Radioterapéutica
20.
Med Phys ; 29(6): 1007-18, 2002 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-12094970

RESUMEN

IMRT treatment plans for step-and-shoot delivery have traditionally been produced through the optimization of intensity distributions (or maps) for each beam angle. The optimization step is followed by the application of a leaf-sequencing algorithm that translates each intensity map into a set of deliverable aperture shapes. In this article, we introduce an automated planning system in which we bypass the traditional intensity optimization, and instead directly optimize the shapes and the weights of the apertures. We call this approach "direct aperture optimization." This technique allows the user to specify the maximum number of apertures per beam direction, and hence provides significant control over the complexity of the treatment delivery. This is possible because the machine dependent delivery constraints imposed by the MLC are enforced within the aperture optimization algorithm rather than in a separate leaf-sequencing step. The leaf settings and the aperture intensities are optimized simultaneously using a simulated annealing algorithm. We have tested direct aperture optimization on a variety of patient cases using the EGS4/BEAM Monte Carlo package for our dose calculation engine. The results demonstrate that direct aperture optimization can produce highly conformal step-and-shoot treatment plans using only three to five apertures per beam direction. As compared with traditional optimization strategies, our studies demonstrate that direct aperture optimization can result in a significant reduction in both the number of beam segments and the number of monitor units. Direct aperture optimization therefore produces highly efficient treatment deliveries that maintain the full dosimetric benefits of IMRT.


Asunto(s)
Planificación de la Radioterapia Asistida por Computador/métodos , Radioterapia Conformacional/métodos , Algoritmos , Relación Dosis-Respuesta en la Radiación , Neoplasias de Cabeza y Cuello/radioterapia , Humanos , Masculino , Método de Montecarlo , Distribución Normal , Fantasmas de Imagen , Neoplasias de la Próstata/radioterapia , Radiometría , Programas Informáticos
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