Charles B. Burns

Factors Affecting Phantom Scores at Annual Mammography Facility Inspections by the U.S. Food and Drug Administration

RATIONALE AND OBJECTIVES The authors performed this study to evaluate the factors affecting phantom image score at the annual inspection of mammography facilities. MATERIALS AND METHODS In 1997, three U.S. Food and Drug Administration (FDA)-trained inspectors performed inspections of all mammography facilities in North Carolina. All federal and state inspection data were collected and evaluated by using linear regression analysis. Factors affecting the American College of Radiology phantom scores were assessed. RESULTS Phantom score was affected by inspector identity, view box luminance, and optical density. All of these factors had a statistically significant effect on mass score (P < .05). Inspector identity yielded a statistically significant effect on speck group score, fibril score, and total score. Luminance yielded a statistically significant effect on both speck group score and total score. CONCLUSION Phantom scoring should be automated to allow for more consistent interobserver scoring. In addition, radiology facilities can improve the likelihood of receiving a passing phantom score by reducing the ambient light and increasing the view box luminance in the location where the images are evaluated and the phantom is scored routinely. Radiologists should also consider increasing phantom and clinical image optical density to allow for improved phantom testing outcomes.

Comparison of zafirlukast (Accolate) absorption after oral and colonic administration in humans.

AbstractPurpose. This study characterized the gastrointestinal (GI) absorptionof zafirlukast after oral and colonic administration in humans. Methods. Five healthy subjects received zafirlukast solution (40 mg)orally and via an oroenteric tube into the colon in a randomized,crossover fashion. Two additional subjects were dosed into the distalileum. Serial blood samples were obtained and plasma concentrationswere quantitated by HPLC. Results. Mean ± SD pharmacokinetic parameters after oral vs. colonicadministration were: AUC∞ of 2076 ± 548 vs. 602 ± 373 ng*h/mL,respectively, and Cmax of 697 ± 314 vs. 194 ± 316 ng/mL, respectively.Mean colon:oral AUC∞ and Cmax were 0.29 and 0.30, respectively.Median tmax values were 2.0 and 1.35 hr after oral and colonicadministration. First-order absorption rate constants (Ka and Kac) wereestimated from a two-compartment model with first-order elimination.Kac:Ka was <0.5 in 4 of the 5 subjects dosed in the colon. Conclusions. Zafirlukast was absorbed at multiple sites in the GI tract.The rate and extent of zafirlukast absorption was less after colonicthan oral administration. Zafirlukast was significantly absorbed in thedistal ileum. This study demonstrated that gamma scintigraphy, digitalradiography, and fluoroscopy can be used to track the movement andconfirm the location of the oroenteric tube in the GI tract.

Effect of pancreatico-biliary secretions and GI transit time on the absorption and pharmacokinetic profile of ranitidine in humans

AbstractPurpose. Ranitidine plasma concentration vs. time profiles and the extent of ranitidine absorption were examined in the presence and absence of pancreatico-biliary secretions in order to elucidate factors which may contribute to secondary peaks after oral ranitidine administration. Methods. Ranitidine solution (300 mg) was administered to 4 fasting healthy subjects via an indwelling small-bore oroenteric tube located ∼16 cm distal to the pylorus. On 3 consecutive days, subjects randomly received ranitidine alone (control), ranitidine 10 min after 0.04 μg/kg IV cholecystokinin (CCK) sufficient to cause gall bladder emptying into the duodenum, and ranitidine 30 min after inflation of an occlusive duodenal balloon located ∼10 cm distal to the pylorus to prevent pancreatico-biliary secretions from reaching the dosing port or beyond. Small bowel transit time (SBTT; min) was measured by breath H2. Serial blood samples, obtained over 12 hours in each treatment, were analyzed by HPLC to determine ranitidine AUC0−2(ng*h/mL), as well as Cmax(ng/mL) and Tmax(min) of the first and subsequent peaks, if subsequent peaks were observed. Results. Ranitidine AUC0−2and Cmax1, were not altered significantly by treatments; treatment effects on SBTT varied. Secondary peaks were observed in subjects #1 and #3 during the control treatment and subjects #2 and #4 during the CCK treatment. No secondary peaks were observed in any subject during the balloon treatment, and Tmax1was delayed. Conclusions. Results support the hypothesis that pancreatico-biliary secretions (present in the intestinal lumen during control or CCK treatment) and gastrointestinal transit time may influence the occurrence of secondary peaks in ranitidine concentration vs. time profiles.

Educational outreach to mammography facility staff to assist with compliance with the mammography quality standards act in rural North Carolina

RATIONALE AND OBJECTIVES The purpose of this project was to develop and evaluate an educational program targeted at mammography facilities in rural areas of North Carolina that were having difficulty complying with the 1992 Mammography Quality Standards Act (MQSA). MATERIALS AND METHODS Fourteen facilities deemed at risk for closure under MQSA were identified by state inspection personnel. Problems at the facilities were evaluated by a radiologist, a physicist-educator, and a radiation physicist through a written survey, review of phantom and clinical images, and a site visit. Individual advice and instruction were provided on-site by the physicist-educator, with written materials provided in follow-up. A repeat site visit was made 4-6 months after the initial visit. RESULTS Of 51 problems identified at the 12 institutions that completed the program, 35 (69%) were corrected. All facilities that had failing phantom scores at the inspection prior to the intervention had passing scores at the inspection after the intervention. There was a statistically significant increase in the sum of the phantom scores for the facilities offered this intervention compared with those not offered it (P = .03). CONCLUSION This educational program improved mammography quality at participating facilities.

Effects of processing conditions on mammographic image quality

RATIONALE AND OBJECTIVES Any given mammographic film will exhibit changes in sensitometric response and image resolution as processing variables are altered. Developer type, immersion time, and temperature have been shown to affect the contrast of the mammographic image and thus lesion visibility. The authors evaluated the effect of altering processing variables, including film type, developer type, and immersion time, on the visibility of masses, fibrils, and speaks in a standard mammographic phantom. MATERIALS AND METHODS Images of a phantom obtained with two screen types (Kodak Min-R and Fuji) and five film types (Kodak Min-R M, Min-R E, Min-R H; Fuji UM-MA HC, and DuPont Microvision-C) were processed with five different developer chemicals (Autex SE, DuPont HSD, Kodak RP, Picker 3-7-90, and White Mountain) at four different immersion times (24, 30, 36, and 46 seconds). Processor chemical activity was monitored with sensitometric strips, and developer temperatures were continuously measured. The film images were reviewed by two board-certified radiologists and two physicists with expertise in mammography quality control and were scored based on the visibility of calcifications, masses, and fibrils. RESULTS Although the differences in the absolute scores were not large, the Kodak Min-R M and Fuji films exhibited the highest scores, and images developed in White Mountain and Autex chemicals exhibited the highest scores. CONCLUSION For any film, several processing chemicals may be used to produce images of similar quality. Extended processing may no longer be necessary.