A review of the program in space-radiation protection at the Langley Research Center is given. The relevant Boltzmann equations are given with a discussion of approximation procedures for space applications. The interaction coefficients are related to the solution of the many-body Schrodinger equations with nuclear and electromagnetic forces. Various solution techniques are discussed to obtain relevant interaction cross sections with extensive comparison with experiments. Solution techniques for the Boltzmann equations are discussed in detail. Transport computer code validation is discussed through analytical benchmarking, comparison with other codes, comparison with laboratory experiments, and measurements in space. Applications to missions to the Moon and Mars are discussed.

Transport Methods and Interactions for Space Radiations

A respiratory gating technique was developed for radiotherapy of tumors unable to remain stable due to respiration. Irradiation was started and stopped with a microwave oscillator of a linear accelerator controlled by gating signals at specific points in the respiratory cycle. This technique was tested in a phantom specially designed to simulate a patient with lung cancer and in clinical therapy for lung tumors of seven patients. A mask was used to check ventilation in the phantom and airbags were used to measure thoracoabdominal pressure in patients and in the phantom; this enabled us to detect the excursion of the tumors. Low sensitivity film for verification demonstrated the efficacy of this technique. The gated irradiation was proved to ensure more precise radiotherapy for tumors located close to the diaphragm.

Irradiation synchronized with respiration gate

An addendum to the AAPM's TG-51 protocol for the determination of absorbed dose to water in megavoltage photon beams is presented. This addendum continues the procedure laid out in TG-51 but new kQ data for photon beams, based on Monte Carlo simulations, are presented and recommendations are given to improve the accuracy and consistency of the protocol's implementation. The components of the uncertainty budget in determining absorbed dose to water at the reference point are introduced and the magnitude of each component discussed. Finally, the consistency of experimental determination of ND,w coefficients is discussed. It is expected that the implementation of this addendum will be straightforward, assuming that the user is already familiar with TG-51. The changes introduced by this report are generally minor, although new recommendations could result in procedural changes for individual users. It is expected that the effort on the medical physicist's part to implement this addendum will not be significant and could be done as part of the annual linac calibration.

https://www.aapm.org/pubs/reports/RPT_67_Addendum.pdf

Addendum to the AAPM's TG-51 protocol for clinical reference dosimetry of high-energy photon beams.

Stereotactic radiosurgery is facilitated by a technique for computing the doses at various points within the patient's body. In particular, the doses are computed at a relatively high density of points within a fine dose grid (572) and at a relatively low density of points within a coarse dose grid (580). In that fashion, the user can quickly obtain necessary information about the radiation dose distribution before implementation of a proposed treatment plan. An advantageous technique of locating the intersection between the radiation beam and the contour or other surface of the patient is also provided. The method is especially well suited for use with a particular structure which allows one to utilize relatively narrow beam widths as a result of great mechanical accuracy.

Dosimetric technique for stereotactic radiosurgery

https://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(09)60209-9.pdf

Medical issues associated with commercial flights

Radiation Oncology Physics: A Handbook for Teachers and Students

In what case do you like reading so much? What about the type of the radiation protection and dosimetry an introduction to health physics book? The needs to read? Well, everybody has their own reason why should read some books. Mostly, it will relate to their necessity to get knowledge from the book and want to read just to get entertainment. Novels, story book, and other entertaining books become so popular this day. Besides, the scientific books will also be the best reason to choose, especially for the students, teachers, doctors, businessman, and other professions who are fond of reading.

Radiation Protection and Dosimetry: An Introduction to Health Physics

The beam characteristics of radiotherapytreatment units are measured and recorded under circumstances in which transient effects are eliminated. Output measurements are done by averaging several readings. Isodose curves are obtained during a period of irradiation which is large compared with that used in patient treatment. When treatments are given, the therapy unit is assumed to deliver radiation beams that match the data acquired during calibration. We have looked at the energy, field uniformity, and output constancy typical of a number of these machines in their initial stages of operation. Although most can provide their ‘‘reference’’ beam characteristics in a short time, there are exceptions. The implications for patient treatment, port filming, and film dosimetry are discussed.

Teletherapy beam characteristics: The first second

Airline pilots and flight attendants are occupationally exposed to cosmic radiation. There has been uncertainty about how to handle the radiation protection requirements of their unique situation. Calculated dose equivalents associated with typical flight routes and crewmember work patterns have recently been published. The results show that flight attendants and pilots on ordinary subsonic aircraft can receive annual doses approaching 10 mSv y-1. I argue that flight crewmembers should receive specific education regarding the risks to their health from radiation exposure. I also argue that a suitable dosimeter system should be employed to provide crewmembers with information on their total doses. This is of particular importance for pregnant crewmembers who risk exceeding recommended fetal dose limits by working some routes during their pregnancy. In addition to airline crewmembers, business "frequent flyers" may receive significant occupational exposures while traveling. They too need appropriate education in order to assist them in assessing their risks from such exposures. Finally, flying during a large solar proton event would significantly increase the dose that would be received. During such an event, the total dose to the fetus of a pregnant crewmember or passenger might exceed the 0.5 mSv recommended monthly maximum. Warnings and action plans for these special circumstances should be improved. Language: en

Health physics concerns in commercial aviation.

An apparatus and method in the field of X-ray therapy used to treat an intracranial radiation part of a patient The apparatus and method are used to solve the geometrical inaccuracy problems due to a sagging or at inappropriate dosing rate when a small point is used These problems are solved thanks to the present device that includes a linear accelerator for sending energy electrons to a collimator (14) that sends an X-ray region (F1) The collimator (14) comprises a plurality of channels (26) directed towards the region (F1) Each channel (26) has a target (32) which produces an x-ray radiation when the respective target (26) is selectively exposed to electrons The collimator (14) has a cover layer of attenuating material (54) of radiation which extends on the outer surface of the collimator (14), leaving the channels (26) exposed to electrons Preferably, the cover layer (54) has a thickness at least equal to the scope of the energetic electrons

Robert J. Barish

Papers

Radiation Oncology Physics: A Handbook for Teachers and Students

Radiation Protection and Dosimetry: An Introduction to Health Physics

Teletherapy beam characteristics: The first second

Health physics concerns in commercial aviation.

Radiosurgical collimator knife