Today marks the first annual International Day of Medical Physics, recognizing the work of medical physicists worldwide in ensuring and improving the safety and quality of radiation in medicine. Medical physics is broadly divided in three categories: diagnostic radiology, radiation oncology, and nuclear medicine physics. In each discipline, medical physicists are responsible for developing and implementing new technologies to improve the diagnosis/treatment of patients while minimizing the exposure to ionizing radiation. Medical physicists are actively engaged in research and development, as well as clinical work to ensure the safety of patients and clinicians.
Marie Curie was awarded the Nobel Prize in both Physics and Chemistry for her pioneering theory of radioactivity and discovery of Radium and Polonium, and remains the only person to ever be awarded Nobel Prizes in multiple disciplines. Celebrated on the anniversary of her birth, the International Day of Medical Physics draws attention to her legacy and the future of radiation in medicine.
The American Association of Physicists in Medicine has released its report on the effective dose delivered by full-body airport scanners. The conclusion: an effective dose of 11.1 nSv, equivalent to 1.8 minutes of background radiation, or 12 seconds of air travel.
The average corrected air kerma measurement across the systems evaluated was 0.046 μGy (for each master or slave unit which together comprise a scanner). For a standard man of 178.6 cm (510) tall and 73.2 kg (161.4 pounds), the effective dose from a single-pose, two-sided scan was determined to be 11.1 nSv (nSv = 10–9Sv) and the skin dose to be 40.4 nGy (nGy = 10–9 Gy). This effective dose is equivalent to 1.8 minutes of background dose received by the average individual in the U.S. in 2006 and is approximately equivalent to 12 seconds of naturally occurring dose during an average flight.
Great discussion on the relative risks associated with airport backscatter x-ray scanners. Without an adequate radiobiology risk assessment model to supersede the linear non-threshold model, it seems there is perhaps not a cut-and-dry interpretation of the data.
In “The T-Cell Army,” [sub. req.] Jerome Groopman writes about new approaches to curing cancer that involve activating the body’s own immune responses to fight tumors. Recently, researchers have found that the body’s white blood cells can be stimulated to shrink tumors, leading to startling remissions in some patients. For over a hundred years, doctors have relied on chemotherapy and radiation as the only effective ways of treating the disease.
- Click through for the story behind the above images, and for more images of the methods and people from the last century of fighting cancer: http://nyr.kr/ITWoK6
The American Association of Physicists in Medicine (AAPM) acknowledges that medical imaging procedures should be appropriate and conducted at the lowest radiation dose consistent with acquisition of the desired information. Discussion of risks related to radiation dose from medical imaging procedures should be accompanied by acknowledgement of the benefits of the procedures. Risks of medical imaging at patient doses below 50 mSv for single procedures or 100 mSv for multiple procedures over short time periods are too low to be detectable and may be nonexistent. Predictions of hypothetical cancer incidence and deaths in patient populations exposed to such low doses are highly speculative and should be discouraged. These predictions are harmful because they lead to sensationalistic articles in the public media that cause some patients and parents to refuse medical imaging procedures, placing them at substantial risk by not receiving the clinical benefits of the prescribed procedures.
AAPM members continually strive to improve medical imaging by lowering radiation levels and maximizing benefits of imaging procedures involving ionizing radiation.