MDPhysics: A Medical Physics Blog

Streak Artifact Reduction and Enhancement of Pelvic CT Image in a Patient with Hip Replacement

MDPhysics.com — Mon, 01 Mar 2010 02:44:38 +0000

Our Radiation Oncologist recently showed me a pelvis CT image of a male patient who had undergone bilateral hip replacement with forged titanium alloy implants. The patient had early stage prostate cancer, and the doctor wanted to treat this patient with IMRT. The difficulty was to delineate the prostate, seminal vesicles and other organs at risk because of the streak artifacts in the CT images due to high-Z material in the patient. The question came up about how this kind of artifact can be removed or minimized so that the target organ, as well as the organs at risk and other organs can be delineated for treatment planning. I did some research and was able to come up with some good articles on this topic. I am summarizing my findings below for those who are interested to learn or as a reference for those who may have such cases in the clinic.

Streak artifacts in CT images are generated in conventional CT when implanted objects of high atomic number exist in the patient. The artifact and image degradation associated with the kilovoltage (kV) CT imaging in the presence of high atomic number material greatly hinders the ability to delineate tumors and certain organs, particularly in the treatment planning of a prostate patient with hip prostheses. Such a situation, therefore, precludes precise dose calculation. There are several techniques reported that, if used, can minimize such artifacts, thereby enhancing image visualization for the delineation of tumor and other organs.

1- Charmley et al. (1) suggested that the use of CT-MR image registration to define target volumes in pelvic radiotherapy in the presence of bilateral hip replacements could facilitate target definition of prostate patient with hip replacements. However, a number of factors were found to affect image quality and/or the accuracy of target definition. The standard MR couch, different from a CT or linac treatment couch, might result in different patient positions, and the presence of the metallic implants may create significant distortion.

2- Yazdia M. (2) suggested an adaptive approach to metal artifact reduction in helical computed tomography for radiation therapy planning. At that time, they may require manual image post-processing and most CT scanners available in radiation oncology department are not equipped with these features.

3- The artifact image and degradation associated with the kilovoltage (kV) CT imaging in the presence of high atomic number material is greatly reduced with Megavoltage Cone Beam Computed tomography (MV-CBCT). MV-CBCT has been used in image-guided radiotherapy (IGRT) to correct patient setup immediately before treatment. Hansen et al (3) used this technique to treat paraspinous tumors in the presence of orthopedic hardware. It allows rapid acquisition of 3D images that can be registered with the planning CT with millimeter precision and enhance image visualization by exploiting the predominantly Compton scattering of high-energy photons delivered in the MV-CBCT system. Aubin et al. (4) of the Department of Radiation Oncology at UCSF did a study with the support of Siemens Oncology Care systems on the use of Megavoltage Cone Beam CT to complement CT for target definition in pelvic radiotherapy in the presence of hip replacement. They found the MV-CBCT image could be used to clearly visualize the hip prostheses and provide sufficient soft-tissue contrast to help delineate the prostate, bladder and rectum. The artifacts on the kV CT obscure the border between the prostate and anterior wall of the rectum and the interface between the prostate base and the bladder neck. However, the MV-CBCT images were particularly useful to help delineate these structures as well as the lateral extension of the prostate in the axial plane, the seminal vesicles and the lymph nodes. Also, normal anatomy such as pelvic bones, penile bulb, bladder, femoral heads, rectum and small bowel can be delineated with higher accuracy as well. They evaluate this technique for seven patients. For each patient, the MV-CBCT images were imported into the treatment planning system and registered with the original CT using body anatomy contoured on each image set. The target volumes and organs at risk for prostate treatment were contoured using both the CT and the MV-CBCT for single hip replacement, and using only the MV-CBCT for bi-lateral hip prostheses. For the full article, click on: http://bjr.birjournals.org/cgi/reprint/79/947/918

The following two figures taken from Aubin M. at el (4) show the difference between conventional CT and MV-CBCT images:

Chamley N. et al. The use of CT-MR image registration to define target volumes in pelvic radiotherapy in the presence of bilateral hip replacements. BJR 2005; 78:634-636.
Yazdia M. et al. An adaptive approach to metal artifact reduction in helical computed tomography for radiation therapy planning: experimental and clinical studies. Int. J. Radiation Oncol Biol Physics 2005; 62(4): 1224-1231.
Hansen, E.K. et al. Image guided radiotherapy using Megavoltage Cone-Beam Computer Tomography for treatment of paraspinous tumors in the presence of orthopedic hardware. Int. J. Radiation Oncol Biol Physics 2006; 66(2): 323-326.
Aubin M. at el. Use of Megavoltage Cone-Beam CT to complement CT for target definition in pelvic radiotherapy in the presence of hip replacement. Short Communication: British Journal of Radiology 2006.

ABR Radiologic Physics Part 1 Exam – How to Prepare?

MDPhysics.com — Mon, 01 Feb 2010 03:09:47 +0000

With the upcoming ABR Physics exams this summer, we have received several questions in regards to how to prepare. If you are taking Part 1 this summer, concentrate on that; don’t concern yourself with Parts 2 and the Oral examination (just yet). That said, the first thing you will want to do is review the topics covered on Part 1 of the physics exam. Fortunately, the ABR has laid out the subjects you will be tested on in the Initial Certification Study Guide. The ABR has yet (as far as we have heard) to veer from those topics, so you will not be tested on subjects outside their study guide. In fact, the guide is quite accurate in terms of the scope of the questions you will be asked. The next thing you will want to do is gather resources that cover those topics well.

The internet is strewn with information that is helpful in prepping; the resources are scattered through the Web and take time to find. One site worth bookmarking provides lecture notes on several physics topics listed in the Initial Certification Study Guide as well as a few practice questions. Another site with lecture notes on relevant topics is the course site for Diagnostic Radiology Imaging Physics at UW. More practice question can be found here and here (though at this site, you will have to register to access the free tests).

Your main allies will be your own lecture notes and good prep books. While cross-referencing is always helpful, the following texts have been helpful to other students who took the ABR Part 1 Physics exam in the past. The first is “Review of Radiologic Physics” by Walter Huda. The book is 272 pages with over 500 practice questions, and the material covered is high-yield. The next two texts are pricey, but serve as good reference texts to have in your possession. They are “The Essential Physics of Medical Imaging” by Bushberg et al and “Medical Imaging Physics” by William Hendee and E. Russell Ritenour. We have also heard that reviewing Raphex exam questions is also key in preparing. There are still a few copies of the very old exams available for purchase on Amazon.com. You can also find copies of recent exams for free on the Web: Raphex 2006 Questions and Answers, Raphex 1998 Questions, Raphex 1997 Questions and the Raphex 1997 Answers.

Last, but certainly not least, talk to people who have taken the exam within the last few years. They will be able to tell you what the ABR has been stressing on the exam these days. Ask them how they prepped and what they found to be useful. Start early, and with the resources listed above in addition to those you locate on your own, you should be well-prepared to tackle Part 1 with ease and success.

Free Medical Physics Classifieds – Sell, Buy or Advertise

MDPhysics.com — Mon, 11 Jan 2010 03:56:15 +0000

Readers who have been us since the launch of MDPhysics.com in March 2009 know that we started with just a weblog. Shortly thereafter, we added a listing of funding opportunities, a medical physics job board as well as a calendar of medical physics events. In addition, a physics classifieds section has been in the works for awhile, and now with coding complete, we’re excited to add this new functionality to the site. As always, a direct link to the page can be found in the navigation bar at the top of the site. Classifieds listings, like job listings, are free. All ads expire after 50 days and can be removed at anytime using an access code you receive via email. Since your email address will not be listed with the ad (unless you enter it in the item description), all initial correspondence regarding your listing will be through an online contact form.

Right now, the site supports three categories: For Sale, Wanted and Services–all with subcategories of their own. As items are listed (or per your suggestions), these categories may grow or change, as necessary. MDPhysics is a great venue to post notices whether you are selling or in need of new or used physics equipment, books, CDs (or any other media), etc, as our site draws a large audience of medical physicists and medical physics students everyday. Please feel free to share the announcement of the new medical physics classifieds portion of the site with your classmates and colleagues.

Also, stay tuned, as we are also working on another novel functionality for the site, which will hopefully be ready to go live this summer.

Calculating Polarity Correction Factor

MDPhysics.com — Tue, 29 Dec 2009 08:40:23 +0000

AAPM’s TG-51 protocol for clinical reference dosimetry of high-energy photon and electron beams contains many details to which we should pay close attention when performing necessary measurements for the calibration of high-energy beams. One such measurement is calculating the polarity correction factor (P_pol) for ionization chambers used in electron beam dosimetry. Since polarity effects vary with beam quality and other conditions (such as cable position), one must correct for these effects by making measurements each time clinical reference dosimetry is performed. To correct an ion chamber’s raw reading for polarity effects it is necessary to take readings with both polarities applied and tabulate P_pol by the following equation:

P_pol = Abs [(M⁺_raw - M^-_raw)/2M_raw]
M⁺_raw is the reading when positive charge is collected and M^-_raw is the reading when negative charge is collected

There may be some ambiguity when first encountering this equation as to which reading one should use for the M_raw value in the denominator. There are quite a few possibilities, but only one correct answer. So, which reading do you use for M_raw in the denominator?

1- The average of M⁺_raw and M^-_raw
2- The larger value of M⁺_raw and M^-_raw
3- The smaller value of M⁺_raw and M^-_raw
4- Either M⁺_raw or M^-_raw can be selected
5- None of the above

Click here for the answer

Sr-90 Ophthalmic Applicator: Activity in reb/sec or in mCi?

MDPhysics.com — Wed, 16 Dec 2009 07:55:17 +0000

Have you ever seen radioactive material labeled with the units Roentgen – Equivalent – Beta rays/second (reb/sec)? A medical physicist recently told me he came across these units on a Strontium-90 source at his new job while he was taking inventory of radioactive materials. This particular source was labeled with its model and serial number, as usual, but its radioactivity (the strength of the source) was given in Roentgen – Equivalent – Beta rays/second (reb/sec) instead of millicuries (mCi). Since the convention is to use miC when recording source strength in the inventory log book, he was wondering how to convert these units to mCi. Since I had not worked with Sr-90, I didn’t know the answer myself. I spoke to a couple of experienced physicists I know, and surprisingly no one had the answer. Like any good scientist, this peaked my curiosity…so I did some research. I am guessing many physicists may not know the answer, so I am sharing the fruits of my labor and the result of my due diligence in this post. This is for those who, like me, are curious and are interested to learn:

The 1950s marked the first use of Sr-90/Y-90 sources for treating wedge-shaped benign ophthalmic lesions. Because of the long (~28.8 years) half-life of Sr-90, many of these ophthalmic applicators are still in use today. The US NRC now requires that the long lived radioactive sources have accredited calibration traceable to the NIST dose to water standard established in 1978 by Pruitt¹and revised by Soares² in 1991.

Several different units have been used to describe source input of Sr-90/Y-90. Soares described these units and the historical progression of these values³:
1- Roentgen Equivalent Beta (reb)
2- Roentgen Equivalent Physical (rep)
3- Rad
4- Gy

So, what exactly is a “reb”? A reb is equal to “the amount of beta radiation that would produce ionization per unit mass in air equivalent to that produced by 1 R of photons.”⁴

Soares suggested using the conversion factors 0.0093 and 0.00982 (Gy/reb) to convert reb to Gy. For derivation of these conversion factors see Reference 3. According a to recent paper published in Medical Physics by the University of Wisconsin Accredited Dosimetry Laboratory (UWADCL), mCi (1 mCi = 37 MBq) is also used to describe nearly all planar Sr-90 sources⁴. Though for most applicators, these values represent estimated nominal contained activity rather than precisely known or determined values.

If a Sr-90 source is described with reb rather than nominal activity in mCi, one way to find out the activity in mCi is to calibrate the source at an Accredited Dosimetry Calibration Laboratory (ADCL), such as UWADCL, in Gy/sec. Then the activity can be estimated in mCi by using the conversion coefficients derived by Soares to convert reb to Gy¹.

For more information see the following references:
1- J. S. Pruitt. “Calibration of beta-particle-emitting ophthalmic applicators.” NBC special publication No. 250-9, 1978.
2-C. G. Soares. “Comparison of NIST and manufacturer calibration of Sr90+Y90 ophthalmic applicators.” Med. Phys. 22, 1487-1493 (1995).
3- C. G. Soares. “Calibration of ophthalmic applicators at NIST: A revised approach.” Med. Phys. (18), 787-793 (1991).
4- Shannon M. Holmes, John A. Micka, and Larry DeWerd. “Ophthalmic applicators: A review of calibration following the change to SI units.” Med. Phys. 36 (5), 1473-1477, May 2009.

Physics to Medical Physics: Switching Paths

MDPhysics.com — Tue, 01 Dec 2009 01:41:59 +0000

We were recently contacted by an individual who was studying physics at the doctoral level and was interested in switching to a career in medical physics. Switching to a career in medical physics with a Ph.D. in any branch of physics was a relatively easy task, say 20 years ago, but has become increasingly more difficult with the growing number of medical physics degree programs and the restrictions of residency admissions to those who have specifically graduated from an academic program in medical physics. It’s certainly an exciting time to be in medical physics, but it’s become difficult (albeit, not impossible) for those who have not specifically trained in medical physics to join the party. It’s worth mentioning that many past (and current) leaders in our field did not graduate from medical physics degree programs, which makes one wonder how many talented individuals with the potential to contribute to our community are unable to become medical physicists simply because they chose to study a different branch of physics instead.

Those who are thinking of switching to medical physics, however, should not give up, as there are certainly ways to transition to the field. And, of course, where there’s a will, there’s a way. I am unable to publish the email we received, since it included a lot of personal specifics. Instead, I am publishing our response to the individual who contacted us with the hope that it will help others who are in the same boat:

First, I have to tell you that if this was 30-40 years ago, you could switch from your current background to the medical physics profession with great ease. Many well-known medical physicists (including some of the ”greats” of our profession) who made seminal contributions to our field entered “medical physics” with backgrounds similar to yours. Back then, there were only a few academic programs in medical physics, such as Wayne State University (which dates back to the early 70’s), that offered a degree specifically in medical physics. If you had a Ph.D. in physics or a closely-related field (including engineering), you could switch to a career in medical physics by simply getting a job as a medical physicist in a hospital and working under the supervision of a physicist. Alternatively, you could complete a two-year fellowship program at a big cancer institution such as MD Anderson or Memorial Sloan-Kettering. In the late 80’s/early 90’s, more schools started offering degree programs in medical physics. As these programs started growing in number so did the demand for their graduates. Some job and fellowship descriptions started requiring applicants to have graduated from a medical physics program (and these days some have started requiring/giving preference to applicants who have graduated from a CAMPEP-accredited medical physics program).

The fact is, these days, the option to immediately get a job as a medical physicist with a physics degree after graduation is practically obsolete. Even most those with a degree in medical physics do not immediately obtain a job after graduation without any type of post-graduate training (such as a residency or fellowship). This leaves the other option, which is the route most taken: complete post-graduate training, such as a post-doc or residency. The problem is that most of the opportunities are limited to those who have completed a degree program or had graduate training specifically in medical physics. Medical physics residencies and fellowships are highly competitive these days, and as you said in your letter, candidates with medical physics degrees (especially from a CAMPEP-accredited program) have an edge. However, with your background, if you have strong recommendation letters and a compelling essay stating your enthusiasm and reasons for pursuing medical physics, I believe you have a chance to be accepted into a program. I wouldn’t say that it’s a lost cause by any means. What you must concentrate on is articulating the reason for your switch to medical physics. Your intentions should be clear and should be a natural extension of your background, experiences and interest. You must also look at your (what these days is considered a non-traditional) background as an asset rather than a liability. Try to leverage your background and experiences: you bring a lot to the table, but more importantly, you bring a lot to the table that the traditional medical physics Ph.D. does not. You have a chance to offer a different perspective (skill sets, experiences) to any program, which is always a plus in admissions. All these, however, must be articulated–no one reading your application is just going to assume all of this.

That said, you did not mention what particular branch of medical physics you are interested in. From your background, I believe that your odds of getting into a fellowship program in diagnostic physics are much higher rather than a fellowship program in therapeutic physics. Of course, you should pursue your own personal interest at the end of the day; however, you could best leverage your past educational and research experience as a diagnostic medical physicist as opposed to a therapeutic physicist. It is worth mentioning that there are a few residencies/training programs in diagnostic medical physics that do not require a degree in medical physics. Currently, for example, Mayo Clinic is accepting applications for a residency that may be a great fit for you: “The Department of Radiology, Mayo Clinic, Rochester, Minnesota, is offering a clinical medical physics training program focusing on imaging for diagnosis and image-guided interventional procedures … Candidates should possess a recent doctoral degree in medical physics, physics or engineering.” Notice that the program is not restricted to those with only a medical physics doctorate. When applying to residency programs, keep in mind that in 2012 you must have graduated from a CAMPEP-accredited medical physics degree program OR completed a CAMPEP-accredited medical physics residency to be qualified to sit for the boards (ABR certification). In 2014, the rules become such that you must have completed a CAMPEP-accredited medical physics residency to be qualified to sit for the boards (ABR certification).

A last option also exists, which is to pursue a masters degree in medical physics. I have known several experienced Ph.D. scientists/physicists who switched to medical physics by going through a degree program and finishing a masters degree in medical physics. With your background, I believe you would have no problem gaining admissions to an MS program. While plowing out an extra 2 years of schooling may not be the most attractive option, it is your safest bet in terms of then being admitted to a residency program and (if you get an MS at a CAMPEP-accredited program) being certain you will be qualified for ABR certification when 2012 rolls around.

(This is a good time to ask yourself: do you want to work clinically as a medical physicist or do you see yourself doing research as a medical physicist? If you have no desire to work clinically, then you do not need to concern yourself with graduating from accredited programs. So long as you complete a residency or post-doc, you would be able to do research as a medical physicist without the need to sit for the ABR certification exam.)

I will assume that you do want to work clinically. So, in terms of making your application stronger, you may want to consider shadowing a medical physicist at a university hospital. Are there any hospitals associated with your university? Volunteering at a hospital is a good first step, but the most valuable clinical experience you will receive is being able to gain knowledge of the daily duties of a medical physicist. Also, while not a requirement, a strong letter of support from a medical physicist would be beneficial to your application.

Lastly, you mentioned you have been taking pre-med classes. Do not limit yourself to pre-med courses, which are mostly basic science classes (organic chemistry, biology, general chemistry+labs). Take an anatomy class, which while not a pre-med course, is indispensable for a physicist working clinically. I would suggest taking a look at the coursework at medical physics programs and trying to find equivalent or similar courses at your university (or another university nearby):
http://medicalphysics.duke.edu/files/MP-courses-040509.pdf,
http://www.uth.tmc.edu/gsbs/programs/medphys/courses.htm,
http://www.medphysics.wisc.edu/medphys_docs/courses.html

I hope this gives you some ideas in your decision making. I think you are taking some good steps, and I do believe your background will ultimately make you a better medical physicist. I personally believe that if you have a passion for what you are doing and work hard for it, you can achieve anything you want.

If anyone has any additional or supplemental advice for this individual or others looking to switch paths to medical physics, please feel free to share your thoughts by leaving a comment at the bottom of the post.

Open Medical Physics Residency Positions 2009-2010

MDPhysics.com — Mon, 23 Nov 2009 04:17:15 +0000

It’s that time of the year again. No, I’m not talking about the holiday season. I’m talking about medical physics residency application season! Ho, ho ho! Medical physics residency programs are looking to fill positions for next year, so as a reminder to those who are currently applying, here is a round up of CAMPEP-accredited programs (in alphabetical order) currently accepting applications and their deadlines. Direct links are provided to official application information for programs that provide such information on their websites. Also, be sure to check the listing of medical physics job openings for more residency positions as they are announced.

Duke University Medical Physics Residency Program

Number of Positions: 2

Start Date: 7/1/2010

Deadline: 11/30/2009

Henry Ford Health System Diagnostic Imaging Physics Residency Training Program

Number of Positions: 1

Start Date: 7/1/2010

Deadline: 1/1/2010

Kansas City Cancer Center Radiation Oncology Physics Residency

Number of positions: 1

Start Date: 7/1/2010

Deadline: 1/15/2010

Mayo Clinic Clinical Medical Physics Residency

Number of positions: 1

Start Date: 7/1/2010

Deadline: 1/15/2009

Rush University Residency Program in Medical Physics

Number of positions: 1

Start Date: 7/1/2010

Deadline: 2/15/2010

Stanford University Medical Physics Residency Program

Number of Positions: 1

Start Date: 7/1/2010

Deadline: 12/31/2009

Thomas Jefferson Medical Physics Residency Program

Number of positions: 1

Start Date: 7/1/2010

Deadline: 12/31/2009

University of Chicago Medical Physics Residency Training Program in Radiation Oncology Physics

Number of positions: 1

Start Date: 7/1/2010

Deadline: 12/15/2009

University of Iowa Clinical Medical Physics Residency Program in Radiation Oncology

Number of positions: 1

Start Date: 7/1/2010

Deadline: 12/15/2009

University of Louisville Radiation Oncology Physics Residency

Number of positions: 1

Start Date: 7/1/2010

Deadline: 12/15/2009

University of Pennsylvania Medical Physics Training Program

Number of Positions: 3

Start Date: 7/1/2010

Deadline: 12/15/2009

University of Texas M.D. Anderson Radiation Oncology Medical Physics Residency Program

Number of positions: 3

Start Date: 7/1/2010

Deadline: 12/31/2009

University of Texas Southwestern Clinical Medical Physics Residency Program

Number of Positions: 1

Start Date: 7/1/2010

Deadline: 12/15/2009

Virginia Commonwealth University Radiation Oncology Medical Physics Residency Program

Number of Positions: 1

Start Date: 7/1/2010

Deadline: 12/31/2009

Washington University Physics Residency Program

Number of positions: 2

Start Date: 7/1/2010

Deadline: 12/15/2009

Practice ABR Radiologic Physics Oral Board Exam

MDPhysics.com — Mon, 16 Nov 2009 02:46:55 +0000

The University of Texas MD Anderson Cancer Center is offering a Diagnostic Radiologic Physics Mock Oral Board Exam the weekend of April 17-18, 2010. Participation is limited, so sign up early. The practice exam dates have been added to the MDPhysics Event Calendar. The mock exam aims to provide the student with a simulation of the ABR oral exam environment by using similar exam format, questions and board-certified examiners.

This mock exam has been offered internally to physics residents and junior faculty with great success, and participation is now being extended outside MD Anderson. All proceeds (tuition is $500) will support medical physics educational programs at the University of Texas MD Anderson Cancer Center.

After taking the mock board exam, the student will be familiar with his or her individual areas of weakness to improve with additional study before the actual board exam. In addition, the mock board exam will allow for practicing the expression of coherent answers in a risk-free setting. Examiners will provide some guidance and feedback to the student on his or her performance.

For more information proceed to Imaging Physics Department’s education page or contact Georgeann Moore at gmoore@di.mdacc.tmc.edu.

The course brochure and application can be found here.

How Well Do You Know Varian and Elekta?

MDPhysics.com — Sun, 08 Nov 2009 21:32:20 +0000

Varian and Elekta are two world leading (and competing) companies pioneering significant clinical solutions for treating cancer in radiation oncology. Any medical physicist is as familiar with the terms “Varian” and “Elekta” as he is with “x-ray” and “radiation.” In essence, Varian and Elekta are the “giants” in our industry…but how much do you really know about these companies whose names are ubiquitous with medical physics and whose products most of us use everyday?

Elekta was founded in 1972 by the late Lars Leksell, Professor of Neurosurgey at Karolinska Institute, Stockholm, Sweden. Currently, Elekta technologies are used in over 5,000 hospitals across the globe, and each day over 100,000 patients receive diagnosis, treatment or follow-up with the help of a solution from the Elekta Group. Tomas Puusepp, is present President and CEO of ELEKTA Corporation International. Shares of Elekta stock trade on the Nordic exchange OMX with the ticker symbol EKTA B. Interestingly, while Elekta shares trade in Sweden, nearly half of its revenue from equipment sales come from the United States. Elekta corporate headquarters is in Stockholm, Sweden.

Varian Medical Systems, Inc. was founded in the late 1940s as Varian Associates in the late 1940s by a group of scientists with strong connections to Stanford University. The company founders included brothers Russell and Sigurd Varian, inventors of the klystron tube, a high-frequency amplifier for generating microwaves that became an essential component of the modern medical linear accelerator. Since the late 1960s, more than 5,200 Varian Medical Systems linear accelerators have been installed in hospitals and clinics worldwide. In 1999, Varian Associates split its semiconductor, vacuum tubes, and medical device divisions into Varian Semiconductor, Varian Inc, and Varian Medical Systems, respectively. Varian employs approximately 5,000 people in its manufacturing sites and sales/support offices across the globe. Timothy E. Guertin is present president and CEO of Varian Medical System Inc. Varian trades on the New York Stock Exchange (NYSE) with the ticker symbol VAR. Varian corporate headquarters is in Palo Alto, California.

Now, for a little fun to test your knowledge of Varian and Elekta products…After all, knowing and being up-to-date on available clinical solutions is a part of being a physicist. Gauge your familiarity with Varian and Elekta products by naming the competing product for each of the following:

1- If Varian has Acuity, what does Elekta have?

2- If Varian has Eclipse, what does Elekta have?

3- If Varian has Rapid Arc, what does Elekta have?

4- If Elekta has MOSAIQ, what does Varian have?

5- If Elekta has the Leksell Gamma Knife, what does Varian have?

6- If Elekta has Infinity, what does Varian have?

7- If Elekta has Axesse, what does Varian have?

8- If Varian has Aria, what does Elekta have?

9- If Varian has Silhouette, what does Elekta have?

10- If Elekta has Synergy, what does Varian have?

And lastly, a bonus question, if you will, who has the Cyberknife?

Lack of HDR Training in Residency Program (For Physicians and Medical Physicists)

MDPhysics.com — Mon, 19 Oct 2009 00:19:29 +0000

If you graduate from a residency program that does not offer or use an HDR after-loader for patient treatments, what problems, if any, could you encounter at your first job? The answer is simple, if you are expected to treat patients with an HDR after-loader as part of your job responsibilities, you are not qualified to be listed as an Authorized User (AU) in the HDR material license, and hence you cannot independently treat patients with an HDR after-loader. That is, you are not legally able to fulfill this part of your job description. It’s a potentially embarrassing circumstance in addition to one that may inconvenience physician scheduling.

According to NRC 10 CFR part 35.690, if you are not a board certified radiation oncologist, the law requires that you have the following training in order to be listed as an AU in the HDR material license and to treat patients with HDR independently:

You must have completed a structured educational program in basic radionuclide techniques applicable to the use of a sealed source in a therapeutic medical unit that includes:

(i) 200 hours of classroom and laboratory training in the following areas—
(A) Radiation physics and instrumentation;
(B) Radiation protection;
(C) Mathematics pertaining to the use and measurement of radioactivity; and
(D) Radiation biology; and

ii) 500 hours of work experience, under the supervision of an authorized user who meets the requirements in §35.690 or, equivalent Agreement State requirements at a medical institution, involving—
(A) Reviewing full calibration measurements and periodic spot-checks;
(B) Preparing treatment plans and calculating treatment doses and times;
(C) Using administrative controls to prevent a medical event involving the use of byproduct material;
(D) Implementing emergency procedures to be followed in the event of the abnormal operation of the medical unit or console;
(E) Checking and using survey meters; and
(F) Selecting the proper dose and how it is to be administered;
(G) Device operation
(H) Safety procedures for the device use
(I) Clinical use of the device

For more information, visit: http://www.nrc.gov/reading-rm/doc-collections/cfr/part035/part035-0690.html

Considering the above guidelines, these are some useful tips to the following groups of individuals:

For ASTRO: Inform all the Radiation Oncology Residency Program Directors about the law.

For Residency Program Directors: If you don’t have an HDR in your facility, try to get one. HDR training should be a part of every physics residency program.

For Residents: If your program does not have an HDR after-loader or offer HDR after-loader training, make arrangements with sites nearby that possess an HDR after-loader and arrange to complete your 500 hours training there during your residency program.

For Medical Physicists: Share this information with your radiation oncologist colleagues. If you are responsible for amending the material license and are expecting a new radiation oncologist to join the group, be sure he or she has all the relevant paper work (documenting the necessary training) available before leaving his/her institution.

Finally, there is a similar law for medical physicist to be listed as an Authorized Medical Physicist that was previously posted on this blog. Click on this link for further information.