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R Minniti

Publications and source records attributed to R Minniti.

8 recordsLinked to original sources
PubMed2006

Calibration of a 137Cs gamma-ray beam irradiator using large size chambers.

A (137)Cs gamma-ray beam irradiator has been calibrated in terms of air kerma using large size chambers. The available air-kerma rates range between 1.8 microGy/h (0.2 mR/h) and 5.3 mGy/h (0.6R/h). Large-volume chambers were used to characterize the source in terms of the radiation quantity air kerma (and exposure). Two types of chambers with significantly different characteristics and energy responses were used. This work shows that very good agreement can be obtained between the measurements performed with such different types of chambers. An agreement of 0.3% is observed between chambers even for the lowest air-kerma rates measured.

Air↗
PubMed2006

Technical aspects of the Naval Dosimetry Center quality assurance programme.

The purpose of this paper is to describe the technical aspects of the Naval Dosimetry Center (NDC) quality programme. The Navy has been formally monitoring personnel for occupational exposure to ionising radiation since at least 1946. The current system, the DT-702/PD, is the Harshaw 8840 holder and 8841 card. New card and holder checks are performed to verify that the correct LiF elements and holder filters are in the correct location and are of the correct composition. Element correction coefficient (ECC) magnitude and repeatability are also verified. Several quality assurance parameters are checked by a specially designed shipping machine. Calibration cards are used to calibrate each reader and quality control cards are inserted throughout a group of field cards to verify reader operation during the read process. The success of the programme is measured by annual proficiency tests administered by the National Voluntary Laboratory Accreditation Programme and Pacific Northwest National Laboratories.

Calibration↗
PubMed2006

The US radiation dosimetry standards for 60Co therapy level beams, and the transfer to the AAPM accredited dosimetry calibration laboratories.

This work reports the transfer of the primary standard for air kerma from the National Institute of Standards and Technology (NIST) to the secondary laboratories accredited by the American Association of Physics in Medicine (AAPM). This transfer, performed in August of 2003, was motivated by the recent revision of the NIST air-kerma standards for 60Co gamma-ray beams implemented on July 1, 2003. The revision involved a complete recharacterization of the two NIST therapy-level 60Co gamma-ray beam facilities, resulting in new values for the air-kerma rates disseminated by the NIST. Some of the experimental aspects of the determination of the new air-kerma rates are briefly summarized here; the theoretical aspects have been described in detail by Seltzer and Bergstrom ["Changes in the U.S. primary standards for the air-kerma from gamma-ray beams," J. Res. Natl. Inst. Stand. Technol. 108, 359-381 (2003)]. The standard was transferred to reference-class chambers submitted by each of the AAPM Accredited Dosimetry Calibration Laboratories (ADCLs). These secondary-standard instruments were then used to characterize the 60Co gamma-ray beams at the ADCLs. The values of the response (calibration coefficient) of the ADCL secondary-standard ionization chambers are reported and compared to values obtained prior to the change in the NIST air-kerma standards announced on July 1, 2003. The relative change is about 1.1% for all of these chambers, and this value agrees well with the expected change in chambers calibrated at the NIST or at any secondary-standard laboratory traceable to the new NIST standard.

Accreditation↗
PubMed2005

Test of radiation detectors used in homeland security applications.

This work was performed as part of the National Institute of Standards and Technology (NIST) program to support the development of the new American National Standards Institute (ANSI) standards N42.32-2003 and N42.33-2003 for hand-held detectors, and personal electronic dosimeters, as well as to support the Office of Law Enforcement Standards (OLES) and the Department of Homeland Security (DHS) in testing these types of detectors for their use by first responders. These instruments are required to operate over a photon energy range of 60 keV to 1.33 MeV and over a wide range of air-kerma rates. The performance and response of various radiation detectors, purchased by the NIST, was recorded when placed in 60Co, 137Cs, and x-ray beams at different air-kerma rates. The measurements described in this report were performed at the NIST x-ray and gamma-ray radiation calibration facilities. The instruments' response (exposure or dose rate readings) shows strong energy dependence but almost no dependence to different air-kerma rates. The data here reported provide a benchmark in support of current protocols that are being developed for radiation detection instrumentation used in homeland security applications. A future plan is to test these devices, plus other commercially available detectors, against ANSI standards N42.32-2003 and N42.33-2003.

Benchmarking↗
PubMedDate not supplied

The Illness Behavior Assessment Schedule: reliability and validity.

A patient's illness behavior represents an important component of any clinical presentation, and may in itself be pathological. Illness behavior and abnormal illness behavior are not easily evaluated, and considerable disagreement exists as to the criteria for making diagnoses such as "conversion reaction," "hypochondriacal reaction," etc. This paper describes the background, reliability and validity of the Illness Behavior Assessment Schedule (IBAS) which has been developed as a basis for a systematic and standardized approach to illness behavior.

Arthritis↗
PubMedDate not supplied

The attribution of affect in pain clinic patients: a psychophysiological study of the conversion process.

In a study to examine the relationship between the conversion process and physiological correlates of emotional arousal, three key elements of conversion were assessed separately in patients experiencing chronic pain for which no adequate somatic cause could be demonstrated. Thirty-seven patients referred to a pain clinic were categorized as members of either high, intermediate, or low conversion groups on the basis of their scores on the Disease Conviction, Affective Disturbance and Denial scales of the Illness Behaviour Questionnaire (IBQ). All patients scored in the high range on Disease Conviction. High conversion patients acknowledge little dysphoric affect and denied life problems apart from physical illness. Intermediate conversion patients also denied life problems other than somatic, but acknowledged high levels of dysphoria. Low conversion patients reported dysphoria and acknowledged life problems which they did not attribute to physical illness. The prediction that the high conversion group would show lower levels of resting skin conductance than the low conversion group was confirmed. Patients in the intermediate conversion group resembled those in the high conversion group in that their resting skin conductance was significantly lower than that observed in members of the low conversion group. These findings are consistent with those of previous studies of conversion disorders. They point to the importance in these conditions of the interaction between dysphoria and the cause to which it is attributed by the patient.

Adult↗