Lawrence N. Rothenberg

Recommendations on performance characteristics of diagnostic exposure meters: Report of AAPM Diagnostic X‐Ray Imaging Task Group No. 6

Task Group 6 of the Diagnostic X-Ray Imaging Committee of the American Association of Physicists in Medicine (AAPM) was appointed to develop performance standards for diagnostic x-ray exposure meters. The recommendations as approved by the Diagnostic X-Ray Imaging Committee and the Science Council of the AAPM are delineated in this report and provide specifications on meter precision, calibration accuracy, calibration reference points, linearity, energy dependence, exposure rate dependence, leakage, amplification gain settings, directional dependence, the stem effect, constancy checks, and calibration intervals. The report summarizes recommendations for meters used in mammography, general purpose radiography including special procedures, computed tomography, and radiation safety surveys for x-ray radiography.

A patient‐equivalent attenuation phantom for estimating patient exposures from automatic exposure controlled x‐ray examinations of the abdomen and lumbo–sacral spine

The Joint Commission on Accreditation of Healthcare Organizations requires diagnostic radiology facilities to known the approximate amount of radiation received by an average patient during radiographic examinations at the facility. Automatic exposure controlled (AEC) techniques are used for many of these exams, and a standard patient-equivalent phantom is necessary when estimating patient exposure on such systems. This is of particular importance if exposures are to be compared among AEC systems with different entrance x-ray spectra. We have developed a phantom, LucA1 Abdomen, to facilitate determining the average patient exposure from AEC anteroposterior (AP) abdomen and lumbo-sacral (LS) spine radiography. The phantom is relatively lightweight, transportable, sturdy, and made of readily available inexpensive materials (Lucite and aluminum). It accurately simulates the primary and scatter transmission through the soft tissue and L-4 spinal regions of a patient-equivalent anthropomorphic phantom for x-ray spectra typically used in abdomen/LS spine radiography. A clinical evaluation to verify the patient-equivalence of three commercial anthropomorphic phantoms (Humanoid, Rando, 3-M) and two acrylic/aluminum phantoms (ANSI and LucA1 Abdomen) has been conducted. The design and development of the LucA1 Abdomen phantom and the evaluation of all phantoms is described.

Radiation dose reduction at a price: the effectiveness of a male gonadal shield during helical CT scans

BackgroundIt is estimated that 60 million computed tomography (CT) scans were performed during 2006, with approximately 11% of those performed on children age 0–15 years. Various types of gonadal shielding have been evaluated for reducing exposure to the gonads. The purpose of this study was to quantify the radiation dose reduction to the gonads and its effect on image quality when a wrap-around male pediatric gonad shield was used during CT scanning. This information is obtained to assist the attending radiologist in the decision to utilize such male gonadal shields in pediatric imaging practice.MethodsThe dose reduction to the gonads was measured for both direct radiation and for indirect scattered radiation from the abdomen. A 6 cm3 ion chamber (Model 10X5-6, Radcal Corporation, Monrovia, CA) was placed on a Humanoid real bone pelvic phantom at a position of the male gonads. When exposure measurements with shielding were made, a 1 mm lead wrap-around gonadal shield was placed around the ion chamber sensitive volume.ResultsThe use of the shields reduced scatter dose to the gonads by a factor of about 2 with no appreciable loss of image quality. The shields reduced the direct beam dose by a factor of about 35 at the expense of extremely poor CT image quality due to severe streak artifacts.ConclusionImages in the direct exposure case are not useful due to these severe artifacts and the difficulties in positioning these shields on patients in the scatter exposure case may not be warranted by the small absolute reduction in scatter dose unless it is expected that the patient will be subjected to numerous future CT scans.

Imaging in three‐dimensional conformal radiation therapy

By and large, radiation therapy is a noninvasive method of the treatment of cancer requiring knowledge of the precise location and extent of the disease to be destroyed and the organs to be protected from radiation damage. Images have always played a central role in providing the requisite information for this mode of cancer treatment. Different types of images, such as computed tomography (CT); magnetic resonance imaging (MRI), positron emission tomographic (PET), simulator, etc., are used to varying degrees depending upon their relevance to radiation oncology as well as their accessibility. It is often necessary to merge data from various types of images. The availability of three‐dimensional information from tomographic images has allowed the introduction of three‐dimensional conformal radiation therapy (3DCRT) methods. Images are employed for diagnosing and establishing the extent of the disease, planning and delivery treatments, and evaluating the effectiveness of the treatment in controlling the disease and assessing the damage to normal tissues. Each image type has a unique informational content of importance to radiation oncology. To extract the maximum information from images, it is necessary to employ various image processing tools. These tools allow us to perform such functions as (1) image enhancement; (2) image correlation to register information from various images; (3) segmentation of images to extract the surface outlines of the tumor volume and normal anatomic structures; and (4) two‐ and three dimensional data visualization. One important aspect of planning radiation treatments is the computation of dose distribution in the patient for a proposed configuration of radiation beams. This step requires tracing rays in a three‐dimensional CT image data set to compute radiologic path lengths through the patients body. Although images are employed to a great advantage in radiation oncology, many problems still remain to be solved. Of the various 3DCRT tasks, the outlining of contours of the volume of intended treatment and normal anatomy on images is highly labor‐intensive and fraught with uncertainty. In addition, the integration of data from various imaging modalities is difficult and error prone because of distortions inherent in imaging and also because of the motion, deformation, and displacement of patients and their internal anatomy. Investigations are in progress to find solutions to these problems.

Physicists in mammography--a historical perspective.

Medical physicists and engineers, working with radiologists and technologists, have made significant contributions in the design of mammographic x-ray units and image receptors, as well as in the development of methods for evaluating mammographic image quality and procedures for quality control. More accurate methods of measuring radiation exposure in the energy range of mammography and more relevant calculations of radiation dose to breast tissue at risk have also been realized. This article will discuss some of the major contributions made by medical physicists for the benefit of mammography. Contributions of radiologists in mammography have been published elsewhere [Bassett, Gold, and Kimme-Smith (1994)]. All contributions cited in this article are based on referenced publications and citations in the following: Medical Physics; Radiology; NCRP Report No. 85; Quality Determinants in Mammography; AAPM Report No. 29; Reduced Dose Mammography, W. W. Logan and E. P. Muntz (editors); RSNA Categorical Course: Technical Aspects of Breast Imaging, A. Haus and M. Yaffe (editors); Film Processing in Medical Imaging, A. G. Haus (editor); Screen-Film Mammography: Imaging Considerations in Medical Physics, G. T. Barnes and G. Donald Frey (editors). The article is divided into six sections: (1) x-ray equipment and receptor development, (2) image quality, (3) radiation dose, (4) phantoms, (5) quality assurance, (6) digital mammography, and (7) reports and committees.

Jean St. Germain, M.S.

It is with great sadness that we share that Jean St. Germain, our colleague, friend, and integral member of the Medical Physics Department at Memorial Sloan Kettering Cancer Center (MSKCC) for over 50 yr, passed away on December 7, 2017. She died peacefully and was with her brother, Amos, at the time. Following completion of graduate study at Rutgers University and a fellowship at Brookhaven National Laboratory, Jean was appointed, in November 1967, as a Fellow in the Department of Medical Physics at Memorial Sloan Kettering under John Laughlin and Garrett Holt. At the end of her fellowship, she was appointed to the faculty and rose to the rank of Associate Attending Physicist, and subsequently, to Attending Physicist. She served as the Corporate Radiation Safety Officer, guiding and presiding over the incredible growth of the institution. She served as an interim chair of the Department of Medical Physics from 2007 to 2010 and subsequently as a Vice-Chair for Clinical and Educational Affairs and Clinical Member. Jean was a licensed medical physicist in New York State and was certified in Comprehensive Health Physics in 1974 by the ABHP and in 1991 in Medical Health Physics by the ABMP. Jean was also appointed a Lecturer, Instructor, and ultimately Assistant Professor of Physics in Clinical Radiology, Weill College of Medicine, Cornell University and served as the Radiation Safety Officer at the NY Presbyterian Weill Cornell Medical Center for more than 35 yr. Jean’s contributions to the field of medical physics and health physics were vast and significant. She has served several professional societies in key leadership roles. She served AAPM as National Secretary, Chair of the Rules Committee, Parliamentarian, founding Chair of the Development Committee, Member of the Governing Board of the AIP, Treasurer of the American Academy of Health Physics, Chair of the Examining Panel in Medical Health Physics and Vice-Chair of the American Board of Medical Physics. She has served four terms on the AAPM Board of Directors. In the Greater New York area, she served as the President of the Radiological and Medical Physics Society (RAMPS, the NYC Chapter of the AAPM) and served three terms as the President of the Greater NY Chapter of the HPS. Jean was a member of the Scientific Committee (SC) for the National Council on Radiation Protection and Measurements (NCRP) that produced NCRP Report No. 105 on radiation protection of medical and allied health personnel. Jean later served as the Chairman of the SC that produced NCRP Report No. 155 on the management of radionuclide therapy patients. In addition, Jean served as a member of several New York State advisory committees on medical and radiological health. She also served as a special examiner for the New York State Civil Service Commission. Jean received many honors and awards during her career. She was a Fellow of the Health Physics Society and of AAPM. She was presented the Failla Award by the Greater NY Chapter HPS and RAMPS. She received the AAPM Distinguished Service Award in 2001 as well as the Varian Award for best professional paper in the Journal of Applied Clinical Medical Physics in 2004. And in 2015, Jean was presented with the Marvin M. D. Williams Professional Achievement Award by the AAPM. The award recognizes AAPM members for an eminent career in medical physics with an emphasis on clinical medical physics. Jean was an excellent lecturer and teacher. She taught Health Physics and Radiation Safety to generations of medical physicists, radiologists, radiation oncologists, nuclear medicine physicians, radiotherapists, radiologic technologists, lab scientists, and others at MSKCC, Weill Cornell Medical Center and throughout the medical physics and radiological community. Jean St. Germain 1945–2017

WE‐G‐224‐01: History Symposium ‐ Historical Aspects of Brachytherapy

This presentation will review some of the historic developments in brachytherapy treatment. The early history of brachytherapy is primarily the history of radium and its daughter products, particularly 222Rn. Much of this history is interwoven with the histories of institutions in North America and Europe, such as the Memorial Hospital, Harvard Medical School, the Huntington Memorial Hospital, closed in 1941, with its activities transferred to the Massachusetts General Hospital, M.D. Anderson Hospital, the Mayo Clinic, the Radium Institute of Paris, the Radium Hemmet in Stockholm and the Holt Radium Institute in Manchester. Noted personalities such as William Duane, Gioacchino Failla, Robert Abbe, Henry Janeway, Victor Hess and Enrico Fermi all worked with “radium cows” which supplied radon gas in seeds and tubes for treatment. Edith Quimby and Herbert Parker made significant advances in dosimetry, developing systems for planar implants and more complex geometries. Noted physicians such as Gilbert Fletcher, Ulrich Henschke, Luis Delclos and Nisar Syed developed applicators and procedures for using radioactive sources for treatment. Modern brachytherapy techniques were developed in the 1960s with the search for radium‐substitute materials including 125I and 192Ir. This time period also saw the development of remote afterloading by Henschke and his associates and the adaptation of computertechnology which facilitated the development of more accurate, user friendly techniques of dosimetry. In the modern era, remote afterloading in conjunction with high dose rate radioactive sources (HDR) and the use of 125I and 103Pd seeds have become staples of modern treatment.

Anniversary paper: Activities of the American Association of Physicists in Medicine 1999-2008.

1999 Geoffrey Ibbott 2000 Kenneth Hogstrom 2001 Charles Coffey 2002 Robert Gould 2003 Martin Weinhous 2004 G. Donald Frey 2005 Howard Amols 2006 E. Russell Ritenour 2007 Mary Martel 2008 Gerald White