Effective half life of iodine for five thyroidectomy patients using an in vivo gamma camera approach.

J Radiat Res (Tokyo). 2007 Nov;48(6):485-93

Authors: Chen CY, Chang PJ, Changlai SP, Pan LK

The effective half-life of radioactive iodine for (near) thyroidectomy patients was evaluated using an in vivo gamma camera approach. Five patients with post administered iodine for remnant ablation of thyroid were thoroughly scanned in vivo for one to four weeks. Derived data were analyzed in a MATLAB program to revise the ICRP recommended effective half-life and, thus, to offer a more reliable dose predication protocol from a health physics viewpoint. A quantitative index, AT (Agreement), was also introduced to specify the deviation between the actual measurement and the results fitted in MATLAB for each patient. The ATs were evaluated as 1.52 +/- 1.54 and 14.05 +/- 11.01 for the thyroid compartment and the remainder, re-spectively, indicating a slight discrepancy between the computed and practical results for the remainder. The actual effective half-life of iodine in the thyroid or the body fluid compartment shifted from 7.3d or 0.24 d to only 0.61 +/- 0.50 d or 0.49 +/- 0.23 d, respectively. Additionally, the integrated T(eff) for the remainder (both body fluid and whole body compartments) was still about 5.8d, since the body fluid and the whole body compartment was inseparable in real whole body scanning. The branching ratio from body fluid compartment to the thyroid and the excretion compartment also changed from 30% and 70% to 11.6 +/- 14.0% and 88.4 +/- 14.6%, respectively. The thyroid was the dominant compartment for a healthy person in the traditional biokinetic model. However, this dominant compartment was shifted to both thyroid and body fluid, based on analyses of the data following thyroidectomy, for the patients herein.

PMID: 17971626 [PubMed - in process]

Medical device and radiological health regulations come of age.

FDA Consum. 2006 Jan-Feb;40(1):58-65

Authors: Rados C

PMID: 16528829 [PubMed - indexed for MEDLINE]

Radiation in the cardiac catheter laboratory.

Heart. 2005 Dec;91(12):1615-20

Authors: Partridge J

PMID: 16287755 [PubMed - indexed for MEDLINE]

A survey of incidents in radiology and nuclear medicine in the West of Scotland.

Br J Radiol. 2005 Oct;78(934):913-21

Authors: Martin CJ

Data on 606 incidents in radiology and nuclear medicine departments reported to a central health physics service have been analysed and causes reviewed. 85% of incidents in radiology departments and 37% in nuclear medicine were overexposures of patients. 80% of these resulted from human error or procedural failure, and of these 32% were mistakes by the referrer. Other incidents in nuclear medicine were contamination events (49%) and failure in management of radioactive materials (10%). Effective doses for patient overexposures covered a broad range with those for CT being 1 mSv and above, while those for other radiology examinations were mostly less than 2 mSv. Reporting of patient overexposure incidents in radiology has increased by four-fold in recent years. The average numbers reported during the last 3 years were 91 per year in radiology and 12 per year in nuclear medicine, for hospitals with a population base of 2.8 million. Incident investigations demonstrated the importance of robust procedures and defences to identify mistakes that could lead to incidents. The central incident reporting and investigation system has raised the awareness of staff about the type of mistakes which could lead to incidents and promoted the introduction of recommended actions to reduce these risks.

PMID: 16177014 [PubMed - indexed for MEDLINE]

Flat-panel-detector chest radiography: effect of tube voltage on image quality.

Radiology. 2005 May;235(2):642-50

Authors: Uffmann M, Neitzel U, Prokop M, Kabalan N, Weber M, Herold CJ, Schaefer-Prokop C

PURPOSE: To compare the visibility of anatomic structures in direct-detector chest radiographs acquired with different tube voltages at equal effective doses to the patient. MATERIALS AND METHODS: The study protocol was approved by the institutional internal review board, and written informed consent was obtained from all patients. Posteroanterior chest radiographs of 48 consecutively selected patients were obtained at 90, 121, and 150 kVp by using a flat-panel-detector unit that was based on cesium iodide technology and automated exposure control. Monte Carlo simulations were used to verify that the effective dose for all kilovoltage settings was equal. Five radiologists subjectively and independently rated the delineation of anatomic structures on hard-copy images by using a five-point scale. They also ranked image quality in a blinded side-by-side comparison. Average ranking scores were compared by using one-way analysis of variance with repeated measures. Data were analyzed for the entire patient group and for two patient subgroups that were formed according to body mass index (BMI). RESULTS: The visibility scores of most anatomic structures were significantly superior with the 90-kVp images (mean score, 3.11), followed by the 121-kVp (mean score, 2.95) and 150-kVp images (mean score, 2.80). Differences did not reach significance (P > .05) only for the delineation of the peripheral vessels, the heart contours, and the carina. This was also true for the subgroup of patients (n = 24) with a BMI greater than and the subgroup of patients (n = 24) with a BMI less than the mean BMI (26.9 kg/m(2)). At side-by-side comparison, the readers rated 90-kVp images as having superior image quality in the majority of image triplets; the percentage of 90-kVp images rated as "first choice" ranged from 60% (29 of 48 patients) to 90% (43 of 48 patients), with a median of 88% (42 of 48 patients), among the readers. CONCLUSION: Delineation of most anatomic structures and overall image quality were ranked superior in digital radiographs acquired with lower kilovoltage at a constant effective patient dose.

PMID: 15858104 [PubMed - indexed for MEDLINE]

Physics applications in nuclear medicine: progress on many fronts.

J Nucl Med. 2005 Feb;46(2):16N, 19N-20N, 22N

Authors: Stabin N, Brill AB

PMID: 15756748 [PubMed - indexed for MEDLINE]

ACCF/AHA/HRS/SCAI clinical competence statement on physician knowledge to optimize patient safety and image quality in fluoroscopically guided invasive cardiovascular procedures: a report of the American College of Cardiology Foundation/American Heart Association/American College of Physicians Task Force on Clinical Competence and Training.

Circulation. 2005 Feb 1;111(4):511-32

Authors: Hirshfeld JW, Balter S, Brinker JA, Kern MJ, Klein LW, Lindsay BD, Tommaso CL, Tracy CM, Wagner LK, Creager MA, Elnicki M, Lorell BH, Rodgers GP, Weitz HH, , , , ,

PMID: 15687141 [PubMed - indexed for MEDLINE]

[Compliance with technical standards for radiological protection at radiation therapy services in São Paulo State, Brazil]

Cad Saude Publica. 2004;20 Suppl 2:S256-67

Authors: Eduardo MB, Novaes HM

Radiation therapy services provide essential therapeutic procedures for cancer, one of the main causes of population morbidity and mortality. Despite their importance in the health system and their potential risks due to the use of ionizing radiation, there are few studies on such services. We evaluated compliance with technical standards for radiological protection in radiation therapy services in Sao Paulo State, Brazil. Forty-nine services were studied in 2000 through interviews with technical staff. Typologies of performance profiles focusing on structure and process variables were constructed and services compared. Important differences were observed in the services' positions in the health care system, level of complexity, and geographic distribution, with better average performance in structural conditions but very inadequate performance in patient protection, indicating the need for more effective health surveillance.

PMID: 15608939 [PubMed - indexed for MEDLINE]

Medical ethics, clinical research, and special aspects in nuclear medicine.

Q J Nucl Med Mol Imaging. 2004 Sep;48(3):175-80

Authors: Corrao S, Arnone G, Arnone S, Baldari S

Medical ethics is the science of survival. It studies the working out of judgments on right or wrong referred to the human being as a biological entity interacting with the whole ecosystem. Medical ethics in clinical research raises numerous moral and technical issues. Methodological aspects are essential for carrying out the aim of clinical research. Medical ethics documents are inspired by the Nuremberg Code and culminate in the recently updated Helsinki Declaration of 1964. In Italy 2 ministerial decrees in 1997 and 1998 laid the basis for the work of a medical ethics committee. They acknowledge the European Good Clinical Practice Guidelines and set professional needs within ethical committees. In clinical research the use of ionising radiation merits special consideration. In the recent past, serious human rights abuses in radiation experiments of the 1950s and 1960s have been found. As regards research in this field we can refer to the publication of the International Commission on Radiological Protection (ICRP) and to the report of the World Health Organisation (WHO). Legislative decree no. 187 of May 26, 2000, which transposed the 97/43/ EURATOM Directive represents the most comprehensive and recent normative reference to clinical research using ionising radiation. However, law no. 39 of March 1, 2002 is important for the partial modifications of previous decrees (art. 108 of L.D. no. 230 of March 17, 1995 and, art. 4 and attachment III of L.D. no. 187 of May 26). In this paper medical ethics, research, methodological issues and aspects of ionizing radiation are discussed.

PMID: 15499290 [PubMed - indexed for MEDLINE]

[The evolution of the system of radiological protection: outline of new ICRP recommendations]

Nippon Hoshasen Gijutsu Gakkai Zasshi. 2004 Jun;60(6):796-801

Authors: Kawasaki H

PMID: 15220866 [PubMed - indexed for MEDLINE]

AAPM/RSNA physics tutorial for residents. Topics in US: B-mode US: basic concepts and new technology.

Radiographics. 2003 Jul-Aug;23(4):1019-33

Authors: Hangiandreou NJ

Ultrasonography (US) has been used in medical imaging for over half a century. Current US scanners are based largely on the same basic principles used in the initial devices for human imaging. Modern equipment uses a pulse-echo approach with a brightness-mode (B-mode) display. Fundamental aspects of the B-mode imaging process include basic ultrasound physics, interactions of ultrasound with tissue, ultrasound pulse formation, scanning the ultrasound beam, and echo detection and signal processing. Recent technical innovations that have been developed to improve the performance of modern US equipment include the following: tissue harmonic imaging, spatial compound imaging, extended field of view imaging, coded pulse excitation, electronic section focusing, three-dimensional and four-dimensional imaging, and the general trend toward equipment miniaturization. US is a relatively inexpensive, portable, safe, and real-time modality, all of which make it one of the most widely used imaging modalities in medicine. Although B-mode US is sometimes referred to as a mature technology, this modality continues to experience a significant evolution in capability with even more exciting developments on the horizon.

PMID: 12853678 [PubMed - indexed for MEDLINE]

Calibration frequency of DAP meters.

Br J Radiol. 2001 Nov;74(887):1078-9

Authors: Nettleton JS, Gill JR

PMID: 11709480 [PubMed - indexed for MEDLINE]

Care of a terminally ill patient following a thyroid ablation dose of (131)I-sodium iodide.

Br J Radiol. 2001 Nov;74(887):1077-8

Authors: Denman AR, Martin S

PMID: 11709478 [PubMed - indexed for MEDLINE]

ERPET training course: establishment of reference levels in diagnostic radiology. European Radiation Protection, Education and Training.

Br J Radiol. 2000 Dec;73(876):1243-5

Authors: Corbett RH, Faulkner K, Fong R

PMID: 11205665 [PubMed - indexed for MEDLINE]

The AAPM/RSNA physics tutorial for residents. MR imaging safety considerations. Radiological Society of North America.

Radiographics. 1999 Nov-Dec;19(6):1641-51

Authors: Price RR

Experience and research over the past decade have demonstrated that diagnostic magnetic resonance (MR) imaging is a biologically safe imaging modality. Specifically, there is currently no convincing evidence that there is any long-term or irreversible biologic effects associated with the radiation and magnetic fields used in MR imaging, specifically radio-frequency (RF) radiation, static magnetic fields, and time-varying gradient fields. However, numerous hazards of MR imaging do exist that can cause severe injuries or even death. These hazards are primarily the result of (a) strong magnetic fields and the strong force that they exert on ferromagnetic objects brought into their influence, including interference with electronic devices such as pacemakers and other implanted electronic devices, and (b) RF burns resulting from inadvertently induced currents in conductive loops placed on the patient's skin surface (eg, electrocardiographic leads and other monitoring devices). Other potential concerns are peripheral nerve stimulation resulting from rapidly switched gradients and auditory noise levels. Establishing a complete and coordinated educational program for all MR imaging facility personnel and conducting effective screening and preparation of patients scheduled for MR imaging procedures are essential to avoid accidents and RF burns and to maintain a safe MR imaging facility.

PMID: 10555679 [PubMed - indexed for MEDLINE]

Radiation detectors in nuclear medicine.

Radiographics. 1999 Mar-Apr;19(2):481-502

Authors: Ranger NT

Single-photon-emitting or positron-emitting radionuclides employed in nuclear medicine are detected by using sophisticated imaging devices, whereas simpler detection devices are used to quantify activity for the following applications: measuring doses of radiopharmaceuticals, performing radiotracer bioassays, and monitoring and controlling radiation risk in the clinical environment. Detectors are categorized in terms of function, the physical state of the transducer, or the mode of operation. The performance of a detector is described by the parameters efficiency, energy resolution and discrimination, and dead time. A detector may be used to detect single events (pulse mode) or to measure the rate of energy deposition (current mode). Some detectors are operated as simple counting systems by using a single-channel pulse height analyzer to discriminate against background or other extraneous events. Other detectors are operated as spectrometers and use a multichannel analyzer to form an energy spectrum. The types of detectors encountered in nuclear medicine are gas-filled detectors, scintillation detectors, and semiconductor detectors. The ionization detector, Geiger-Müller detector, extremity and area monitor, dose calibrator, well counter, thyroid uptake probe, Anger scintillation camera, positron emission tomographic scanner, solid-state personnel dosimeter, and intraoperative probe are examples of detectors used in clinical nuclear medicine practice.

PMID: 10194791 [PubMed - indexed for MEDLINE]

Distance learning in mammographic digital image processing.

Br J Radiol. 1998 Feb;71(842):167-74

Authors: Costaridou L, Panayiotakis G, Sakellaropoulos P, Cavouras D, Dimopoulos J

The potential of interactive multimedia and Internet technologies is investigated with respect to the implementation of a distance learning system in medical imaging. The system is built according to a client-server architecture, based on the Internet infrastructure, composed of server nodes conceptually modelled as World Wide Web (WWW) sites. Sites are implemented by integration and customization of available components. The system evolves around network-delivered interactive multimedia courses and network-based tutoring, which constitute its main learning features. This potential has been demonstrated by means of an implemented system, validated with digital image processing content, specifically image enhancement. Image enhancement methods are theoretically described and applied on mammograms. Emphasis is given in the interactive presentation of the effects of algorithm parameters on images. The system end-user access depends on available bandwidth, so high speed access can be achieved via LAN or local ISDN connections.

PMID: 9579181 [PubMed - indexed for MEDLINE]

Assessment of the action of mixed irradiation.

Environ Health Perspect. 1997 Dec;105 Suppl 6:1455-8

Authors: Suzuki S

Problems associated with the environmental and health perspectives of mixed irradiation are identified and the application of theoretical models is discussed. Four definitions of synergism were examined with regard to the action of mixed irradiation, and it was determined that all these definitions are inappropriate. Thus, I concluded that the term synergism or its synonym should not be used for the action of mixed irradiation unless a reasonable definition and evidence of the mechanism are provided. The Zaider-Rossi model and the extended Zaider-Rossi model, which can be applied to any type of mixed irradiation with two types of radiation, are useful for assessing the effects of mixed irradiation using the parameters for two types of single irradiation. Furthermore, models were proposed for very short and very long simultaneous mixed irradiation with multiple types of radiation. These models also would be helpful to assess the environmental and health perspectives of mixed irradiation.

PMID: 9467062 [PubMed - indexed for MEDLINE]

Dosimetry overview: keeping score on the scorekeepers.

Cancer. 1997 Dec 15;80(12 Suppl):2501-4

Authors: Wessels BW, Siegel JA

BACKGROUND: As a direct result of the use of the absorbed dose unit the 'Gray' as the gold standard for predicting response in external beam radiotherapy, the physicist role has been essential to clinical practice for many decades. However, although the dosimetry for internal emitters has proven useful in managing health physics concerns and diagnostic nuclear medicine, the relative success of correlating absorbed dose with response from radionuclide therapy has been limited. METHODS: This overview presents the relative success and/or failure of model-based dosimetry for radionuclide therapy in comparison to results quoted for external beam therapy dosimetry. RESULTS: Using the standard MIRD formalism for macroscopic dosimetry, the marked non-uniform distribution of radionuclide in both tumor and normal tissue has resulted in limited correlation between computed absorbed dose and biological response in clinical trials. Several efforts are underway aimed at improving this dose-response correlation which include individualized patient specific dosimetry and selected biological parameters. CONCLUSIONS: The physicist role in helping the clinician determining which patients will succeed on given radionuclide therapy has been improved with simplified methods such as the assessment of tracer whole body absorbed dose on a per patient basis. The dose-response correlations are now in the moderate range of significance when individualized patient dosimetry is included. These correlations are expected to improve as unified treatment planning programs are instituted and standard methods of clinically based dosimetry are widely accepted and practiced universally.

PMID: 9406702 [PubMed - indexed for MEDLINE]

The AAPM/RSNA physics tutorial for residents. X-ray production.

Radiographics. 1997 Jul-Aug;17(4):967-84

Authors: McCollough CH

X-rays are produced when highly energetic electrons interact with matter and convert their kinetic energy into electromagnetic radiation. The two unique mechanisms by which x-rays are produced are called the bremsstrahlung and characteristic processes. Bremsstrahlung x-rays produce a continuous x-ray spectrum, whereas characteristic x-rays are produced at specific narrow bands of energies. Many technical parameters of the x-ray production equipment affect the magnitude and shape of the x-ray spectrum. The quantity of x-rays produced varies proportionally to the tube potential squared, tube current, exposure time, and atomic number of the anode material and is inversely proportional to the distance squared. x-ray quantity is also affected by the voltage waveform (generator type) and tube filtration. The shape of the x-ray spectrum is affected by the atomic number of the anode material, tube potential, filtration, and voltage waveform.

PMID: 9225393 [PubMed - indexed for MEDLINE]

Effective communication on radiation risk: who is at fault?

J Nucl Med. 1996 Nov;37(11):1913-4

Authors: Courey MH

PMID: 8917205 [PubMed - indexed for MEDLINE]

Demographic characteristics of physicists who evaluate mammographic units.

Radiology. 1995 Feb;194(2):373-7

Authors: Rothenberg LN, Deye JA, High MD, Jessop NW, Sternick ES

PURPOSE: To determine whether there will be an adequate number of physicists to meet the 1996 American College of Radiology (ACR) Mammography Accreditation Program requirements and assess the qualifications of physicists available to evaluate mammography units as required by the federal Mammography Quality Standards Act of 1992. MATERIALS AND METHODS: A 21-question survey prepared by the ACR was sent to most medical physicists who perform evaluations of mammographic units. Replies were received from 1,011 individuals. RESULTS: Survey results are based on the replies of 824 individuals who indicated a willingness to perform evaluations in the future. In 1996, there will be approximately 510 certified physicists to evaluate an estimated 14,000 mammography units in the United States. CONCLUSION: A sufficient number of certified diagnostic medical physicists will be available to provide required annual performance evaluations of all mammography units in the United States only if the number of units evaluated per physicist increases substantially over current levels.

PMID: 7824712 [PubMed - indexed for MEDLINE]

Mammography quality assurance from A to Z.

Radiographics. 1994 Mar;14(2):371-85

Authors: Farria DM, Bassett LW, Kimme-Smith C, DeBruhl N

Quality assurance (QA) refers to all planned, systematic activities that instill confidence that quality mammography is being performed. Quality control (QC) refers only to the technical aspects of the examination. Standardized labeling of mammograms and the format for mammographic reports are important parts of a QA program; recommendations for both have been published by the American College of Radiology. Minimum staff for a mammography service consists of a scheduler, technologist(s), medical physicist, and radiologist. The scheduler asks the patient questions to ensure that the appropriate examination is performed, gives the patient instructions, and asks the patient to complete a history questionnaire including a release form to obtain earlier mammograms. One certified, licensed technologist is designated to perform QC, which includes maintaining darkroom, screen, and view box cleanliness; reviewing processor performance, checked with sensitometer, densitometer, and phantom images; repeat analysis; analysis of fixative retained in film, darkroom fog, screen-film contact, and adequacy of compression; and visual inspection of equipment. A certified medical physicist performs equipment acceptance testing and annual QC visits thereafter. The radiologist oversees all aspects of the QA program, including selecting and regularly observing the technologists, selecting and meeting with the physicist, communicating results, ensuring patient follow-up, and assessing patient outcome data. The radiologist is ultimately responsible for image quality and the standard of patient care.

PMID: 8190960 [PubMed - indexed for MEDLINE]

Medical physics.

Radiology. 1994 Mar;190(3):945-51

Authors: Wagner LK, Bronskill MJ, Chen GT, Chenevert TL, Gardner E, Gelse R, Madsen M, Ritenour ER, Schueler B, Seibert JA

PMID: 8115661 [PubMed - indexed for MEDLINE]

Radiologic physics instruction for diagnostic radiologists: a survey of residency programs. Committee on Training of Radiologists, American Association of Physicists in Medicine.

AJR Am J Roentgenol. 1991 Aug;157(2):409-10

Authors:

PMID: 1853829 [PubMed - indexed for MEDLINE]

Physics instruction in radiology.

AJR Am J Roentgenol. 1989 Feb;152(2):398-9

Authors: Hendee WR

PMID: 2783520 [PubMed - indexed for MEDLINE]

Radiologic physics instruction for diagnostic radiologists: results of an opinion survey. Committee on Training of Radiologists, American Association of Physicists in Medicine.

AJR Am J Roentgenol. 1989 Feb;152(2):393-7

Authors:

PMID: 2783519 [PubMed - indexed for MEDLINE]

Toxic agent and radiation control: progress toward objectives for the nation for the year 1990.

Public Health Rep. 1988 Jul-Aug;103(4):342-7

Authors: Rall DP

In 1980, the Department of Health and Human Services set national prevention objectives for 1990 in 15 health priority areas, 1 of which is the control of toxic agents and radiation. Ten objectives related to this area are priorities for the national control effort. Progress is reviewed on those priorities within the responsibilities of the Public Health Service. Six key program elements, or types of support activities, are deemed essential to preventing, identifying, and controlling toxic agent and radiation threats. Significant progress has been made toward achieving objectives for which all key program elements have been successfully implemented to provide the requisite know-how, manpower, and tools. Important advances have been made in reducing the blood lead levels of the population, reducing unnecessary exposure to medical X-rays, evaluating the toxicities of chemicals in toxic waste dumps, and improving the scientific and technical information base and its availability for prevention and control efforts. The most important priority for the forseeable future will be to expand our knowledge of potential health risks posed by toxic agents and radiation. Expanded surveillance systems and data bases are essential to determining the extent of the problems in terms of human health effects and for measuring the impact of prevention programs. Emphasis on the activities embodied in the key elements will encourage the expansion of the knowledge base and its effective application to prevention and control problems.

PMID: 3136492 [PubMed - indexed for MEDLINE]

Marshall Brucer still full of acerb wit 30 years after serving as SNM president. Interview by Linda E. Ketchum.

J Nucl Med. 1987 Nov;28(11):1645-50

Authors: Brucer M

PMID: 3312517 [PubMed - indexed for MEDLINE]

Dynamic digital subtraction imaging using fast low-angle shot MR movie sequence.

Radiology. 1986 Aug;160(2):537-41

Authors: Haase A, Matthaei D, Hänicke W, Frahm J

High-quality magnetic resonance (MR) images can be recorded within seconds with the use of fast low-angle shot (FLASH) MR imaging. This technique also gives new access to the time evolution of both periodic functions, such as cardiac motion, and nonperiodic physiologic processes, such as flow within internal organs. The time course and regional distribution of dynamic processes detectable by FLASH MR movies are often demonstrated best within series of difference images obtained by digital subtraction of the original data, especially after the use of MR contrast agents. In addition, quantitative information is provided by the analysis of time-intensity profiles for selected regions of interest. Dynamic digital subtraction MR imaging was evaluated in rabbit brain and kidney using a 2.3-T, 40-cm-bore magnet. The time resolution was 1.5 seconds for brain studies and 28 seconds for kidney studies. The total examination times were 1.5 and 30 minutes, respectively.

PMID: 3523597 [PubMed - indexed for MEDLINE]

Boundary effects from opposed magnetization artifact in IR images.

Radiology. 1986 Aug;160(2):543-7

Authors: Hearshen DO, Ellis JH, Carson PL, Shreve P, Aisen AM

A cancellation of signal intensity at the interface separating selected tissue-equivalent materials is observed in inversion recovery proton MR images. The absence of signal intensity at the interface is always one pixel wide and appears only when the tissue-equivalent materials forming the interface differ substantially in their longitudinal relaxation times (T1). Images were obtained of various two-layer combinations of tissue-equivalent materials consisting of vegetable oil, animal fat, saline, aqueous Mn+2, or 2% agar doped with Mn+2. This type of boundary is compared with chemical shift artifacts, which at 0.15 T and 0.35 T produce a similar effect. A clinical example of the opposed magnetization artifact is also shown. Since tissues with substantially different T1s are found in vivo, it is expected that this effect could lead to an instrument-dependent artifact that could easily be misinterpreted.

PMID: 3014600 [PubMed - indexed for MEDLINE]

James L. Weatherwax: pioneer in the physics of radiology.

Radiographics. 1986 Mar;6(2):331-5

Authors: Stanton L

PMID: 3317543 [PubMed - indexed for MEDLINE]

Resonance by rod-shaped reflectors in ultrasound test objects.

Radiology. 1981 Apr;139(1):189-93

Authors: Hefner LV, Goldstein A

Rod-shaped reflectors such as those used in the AIUM test object resonate at medical ultrasound frequencies, producing artifacts posterior to the reflector. Rods of various diameters and materials were examined to determine their resonant properties, and the effect of the Plexiglas scanning surface of the enclosure on image quality was studied. A theory predicting the resonant frequencies of rods is proposed, and methods of eliminating resonance artifacts are discussed.

PMID: 7208920 [PubMed - indexed for MEDLINE]

Proton imaging for medical applications.

Radiology. 1980 May;135(2):485-94

Authors: Kramer SL, Moffett DR, Martin RL, Colton EP, Steward VW

In order to demonstrate the potential advantages of proton imaging for medical use, a 205-MeV proton beam was developed using the Argonne National Laboratory Booster I synchrotron. Data were taken using a narrow scanning beam and an electronic detector system. The dose reduction and an improved mass resulution over the radiographs. The images also show significant differences in the proton stopping power of different tissues, thus demonstrating considerable potential in soft-tissue imaging. The development of a proton tomographic scan system is also briefly discussed.

PMID: 6245430 [PubMed - indexed for MEDLINE]

The health physics of xenon-127.

Radiology. 1980 Feb;134(2):493-5

Authors: Chu RY, Poe ND, Zielinski FW, Ing SJ

Dosimetry calculations were performed for clinical ventilation studies in which xenon-127 was used in place of xenon-133. A graphical method for obtaining the maximum permissible concentrations for a facility that uses both isotopes is presented. Shielding requirements are also described.

PMID: 7352238 [PubMed - indexed for MEDLINE]

The low-temperature scintillation properties of bismuth germanate and its application to high-energy gamma radiation imaging devices.

J Nucl Med. 1979 Dec;20(12):1279-85

Authors: Piltingsrud HV

Bismuth germanate is a scintillation material with very high z, and high density (7.13 g/cm3). It is a rugged, nonhygroscopic, crystalline material with room-temperature scintillation properties described by previous investigators as having a light yield approximately 8% of that of NaI(Tl), emission peak at approximately 480 nm, decay constant of 0.3 microsec, and energy resolution congruent to 15% (FWHM) for Cs-137 gamma radiations. These properties make it an excellent candidate for applications involving the detection of high-energy gamma photons and positron annihilation radiation, particularly when good spatial resolution is desired. At room temperature, however, the application of this material is somewhat limited by low light output and poor energy resolution. This paper presents new data on the scintillation properties of bismuth germanate as a function of temperature from -- 196 degrees C to j0 degrees C. Low-temperature use of the material is shown to greatly improve its light yield and energy resolution. The implications of this work to the design of imaging devices for high-energy radiation in health physics and nuclear medicine are discussed.

PMID: 536796 [PubMed - indexed for MEDLINE]

Nuclear Medicine and Radionuclide Metrology ICRM Life Sciences Working Group.

J Nucl Med. 1979 Sep;20(9):998-9

Authors: Woods MJ

PMID: 536851 [PubMed - indexed for MEDLINE]

Professor Moeller clarifies attribution and other matters.

Am J Public Health. 1979 Jun;69(6):609

Authors: Moeller DW

PMID: 443505 [PubMed - indexed for MEDLINE]

The use of SI units in reporting results obtained in hospital laboratories.

J Clin Pathol. 1974 Jul;27(7):590-7

Authors: Baron DN, Broughton PM, Cohen M, Lansley TS, Lewis SM, Shinton NK

PMID: 4425272 [PubMed - indexed for MEDLINE]

History of the American Board of Health Physics.

Am J Public Health. 1972 Feb;62(2):247-51

Authors: Moeller DW

PMID: 4550906 [PubMed - indexed for MEDLINE]

Radiostrontium localization in metastatic osteosarcoma.

J Nucl Med. 1971 Nov;12(11):767-8

Authors: Samuels LD, Schall GL, Zeiger LS

PMID: 5286516 [PubMed - indexed for MEDLINE]

Professional status of radiation protection personnel.

Am J Public Health. 1971 Oct;61(10):1947-58

Authors: Little MS

PMID: 5096795 [PubMed - indexed for MEDLINE]

Meeting radiological health manpower needs.

Am J Public Health. 1971 Oct;61(10):1938-46

Authors: Moeller DW

PMID: 5096794 [PubMed - indexed for MEDLINE]

Exposure rate at the surface of syringes containing radioactive material.

J Nucl Med. 1971 Aug;12(8):574-6

Authors: Husák V

PMID: 5093431 [PubMed - indexed for MEDLINE]

Results of thyroid and whole-body counting of some medical and paramedical personnel.

J Nucl Med. 1971 Jul;12(7):523-5

Authors: Shleien B, LeCroy E

PMID: 4997173 [PubMed - indexed for MEDLINE]

The character and emphasis of research in nuclear medicine.

J Nucl Med. 1971 Jun;12(6):319-20

Authors: Sisson JC

PMID: 5580854 [PubMed - indexed for MEDLINE]

Changing patterns in radiological health.

Am J Public Health Nations Health. 1969 Dec;59(12):2251-6

Authors: Barber DE

PMID: 5389508 [PubMed - indexed for MEDLINE]

Environmental planning: a health physicist's view.

Am J Public Health Nations Health. 1968 Aug;58(8):1410-3

Authors: Whipple GH

PMID: 5691374 [PubMed - indexed for MEDLINE]

Certification in occupational health: philosophy, implication, and mechanism. 3. The American Board of Health Physics.

Am J Public Health Nations Health. 1966 Jul;56(7):1127-30

Authors: Cowan FP

PMID: 5949772 [PubMed - indexed for MEDLINE]

Some thoughts on interdisciplinary science.

Bull Med Libr Assoc. 1966 Apr;54(2):126-34

Authors: Stannard JN

The development of the "new biology" is largely a story of developments in interdisciplinary science. This paper considers a few of these of special interest to the author and active at the University of Rochester; namely, dental research, biophysics, radiation biology, health physics, biomedical engineering, and space biology. Rochester pioneered advanced academic training in radiation biology, a field which, despite some earlier tendencies to become associated with techniques rather than scientific problems, is now clearly a substantive discipline. Using biophysics as an example, the paper points to the futility of trying to define in detail the exact nature of each new "interdisciplinary discipline," yet it also decries the coining of new names without due cause. Health physics and its related field, radiological health, are described as centered on problems of radiation protection and as professional in their overtones. The interrelationships between engineering and bioscience are seen most clearly in biomedical engineering and the growing programs in space biology which require complete cooperation and mutual understanding between engineers and bioscientists for their ultimate success. After presenting some implications for medical libraries, the paper closes with a plea that the developers of new interdisciplinary fields and their powerful tools maintain historical perspective, simplicity of approach, and respect for nature's infinite resourcefulness.

PMID: 5910383 [PubMed - indexed for MEDLINE]