Physics and Biology Boards Questions

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Trying to get ready for the test and came up with a few questions I was struggling to find answers to. Would appreciated some feedback....

Physics:

1. Is the paired line test simply QA for simulators?

2. If you are trying to set up IMRT with < 10% dose inaccuracy, what leaf position can you accept (is this the same as the recommendations from the most recent AAPM?)

3. If you use heterogeneity corrections for SRS cases how does this affect dose (kind of confused by this because it would be dependent on site with lung (decreased density and increased dose) v. brain (less significant impact)

4. Platinum shielding in I-125/Ir-192: is it for B/low energy gammas for I-125, and low energy gammas for Ir-192

5. if you have a 1 cm pt source and a 3 cm pt source of same activity at a distance of 1.5 cm (where d is not >>> than size of source), how do you quantify the difference in dose rate?

6. Patient treated with lateral field, SSD=100, field=f1. Now needs re-treatment with another lateral field (SSD=100, field=f2), inferior to initial. if you are matching the fields would you just kick the head of the coach towards with the angle being tan-1 (f2/100).

7. With linear brachy sources when do you shift from fall off of 1/r v. 1/r2. Also if you have 2 line sources with same activity (ex. 1 mgRaeq), at a set distance away would the dose rate be higher for the source with smaller active length due to less oblique filtration?

Thanks in advance.
 
"If you use heterogeneity corrections for SRS cases how does this affect dose (kind of confused by this because it would be dependent on site with lung (decreased density and increased dose) v. brain (less significant impact)"

Actually, for lung also depends on if calculating dose at iso/middle of tumor or if prescribing to periphery. If periphery, dose actually is less when add hetero corrections (ie 20Gy x 3 becomes 18Gy x 3 when add heterogeneity).
 
RadRadRad said:
"If you use heterogeneity corrections for SRS cases how does this affect dose (kind of confused by this because it would be dependent on site with lung (decreased density and increased dose) v. brain (less significant impact)"

Actually, for lung also depends on if calculating dose at iso/middle of tumor or if prescribing to periphery. If periphery, dose actually is less when add hetero corrections (ie 20Gy x 3 becomes 18Gy x 3 when add heterogeneity).
Click to expand...

which never made sense to me considering that lung tissue is less dense and with hetero on, you'd think you'd need less MUs than assuming it to be a solid.
 
saw a recall and the question was
"Regarding Kidney Normal Tissue Tolerance: What is measurable in urinalysis at the end of 40 Gy of treatment: proteinuria, hyaline casts, no abnormalities?"

I'm assuming this meant 40 Gy to the whole kidney? If so, then the onset of changes would probably be well after the final day of RT (years even). Not sure what you could detect in urinalysis at that time, proteinuria perhaps?

Another: "what does not have an effect on XRT tolerance? Duration of Tx, Contralateral Nephrectomy, other choices"

Contralateral nephrectomy would affect tolerance but duration of treatment probably wouldn't due to longer cell cycle times and lack of repair capacity right?
 
CAbroiler said:
saw a recall and the question was
"Regarding Kidney Normal Tissue Tolerance: What is measurable in urinalysis at the end of 40 Gy of treatment: proteinuria, hyaline casts, no abnormalities?"

I'm assuming this meant 40 Gy to the whole kidney? If so, then the onset of changes would probably be well after the final day of RT (years even). Not sure what you could detect in urinalysis at that time, proteinuria perhaps?

Another: "what does not have an effect on XRT tolerance? Duration of Tx, Contralateral Nephrectomy, other choices"

Contralateral nephrectomy would affect tolerance but duration of treatment probably wouldn't due to longer cell cycle times and lack of repair capacity right?
Click to expand...

IIRC, I think I've seen this question in a recall before and the answer was "no abnormalities" (at least at the end of treatment 😉)
 
CAbroiler said:
Another: "what does not have an effect on XRT tolerance? Duration of Tx, Contralateral Nephrectomy, other choices"
QUOTE]

I know that RBE for kidney damage increases with decreasing dose per fraction - but not sure what they are getting at with duration of treatment..seems like the key is fractionation, not necessarily time, so I guess I'd go with the duration answer too.
Click to expand...
 
On the assumption that "duration of treatment" = "overall treatment time" (in which case, the question should have read "overall treatment time" and not "duration of treatment" 🙄), then that's the correct answer. For late-responding normal tissues like kidney, there is no time correction required because compensatory proliferation – if any – would occur long after the treatment was over and done with. It's the fractionation sensitivity, and to a lesser extent, the volume irradiated, that are more important in determining the tolerance dose for the kidney.

Incidentally, a tissue that's especially sensitive to size of the dose per fraction is not the same thing as saying that it "lacks repair capacity".

The contralateral nephrectomy issue is a bit confusing though. The remaining kidney will increase in volume if its partner is removed; the question though is whether that is caused strictly by hypertrophy, or whether any actual cell proliferation occurs (given that kidney is one of those relatively rare reverting post-mitotic tissues and, for all we know, may also contain a few stem cells here and there). If the latter, then it could be the case that removal of the contralateral kidney would affect the radiation tolerance of the remaining one...however I'm not sure. 😕

I may be a radiobiologist, but a physiologist I ain't!
 
Anyone still awake know if physics or radbio is first?
 
It was not awesome. The physics was ROUGH. So many out there questions that I don't think I would have been able to answer no matter how much studying I did. Definitely harder than Raphex IMO. What the hell is a circulator? All the parts of a linac and that's the most important part to test us on? Are you freaking kidding me? I felt like instead of testing our knowledge, most questions were intentionally designed to trick you with multiple answers very close to the actual one - really screwed with my mind.

Radbio was better. I felt confident about 60-70% of the answers, then could narrow down most of the rest. But physics was more like 40%. Ouch! I'm hoping it's enough to pass.. It was a very unfilfilling experience to put in all that time and effort and then be tested on the abstract minutia or just have totally screwy questions. Poorly written and unfair test IMO.
 
100% agree. Radbio was fair with many questions similar to the practice exam. Physics was all over the place...not what I expected at all. Compared to the Raphex exams, I think about 30% were along the lines of things I studied.
 
My co-resident felt the same way, as did a buddy of mine from another program. So hopefully we're all in the same boat and will pass. I'm one of those people that always feels legitimately that I fail these standardized tests..but this one takes the cake. The questions were really not cool 😡
 
ROFL to the circulator comment!! i totally agree!

overall, physics did seem sorta all over the place, and all i have to say is that i did way too many SSD/SAD MU questions for that one problem on the test that i dont think i even got right.

radbio was reasonable although there were still a few things i wasn't sure on but much fewer than in physics. i would also say that in both sections, half the time, the syntax and sentence structure was so bad that that make the problems a lot harder than they had to be. - seriously poor quality.

another rant while we're at it, why does it take 3 weeks to get the results of the test!!? it's computerized multiple choice, wouldn't even 1 week be overkill but 3? oh well, guess i can forget about it for at least that much time.

hope it was enough! P = MD (not exactly but you know what i mean in this case)
 
Physics was a nightmare. I got home and tried to look up some of the questions and still could not find the answers. Kahn's book seemed to be of no help at all. The problems requiring calculation were too complicated to be doing on a microsoft calculator. Where were the straightfoward MU checks, relation questions?
 
+1 on the rant about 3 effing weeks for results?!?! At my testing center there were a slew of girls taking their RN test and so I got to hear the Pearson Vue chick explain 9 times that their test would be between 70 and 270 questions depending on how well they did. When their exam was over - FLASH - onto the screen appears whether you passed or failed.

Apparently in our world, since they're still testing us on how many bits a stupid floppy disk can hold, the last ten years of technological advancement have been able to improve radiation delivery, but not a simple thing like test results. Monte Carlo? 114 segment IMRT, no problem - talk to me in 10 minutes. But a 100 question exam - oooh, we're gonna need at least 3 weeks for that one!

Maybe next year, instead of the crappy Microsoft Calculator, they should issue slide-rules for old time's sake.

Sorry, very obviously frustrated here and quite frankly mad at the dorks that wrote this test.
 
napoleondynamite said:
Apparently in our world, since they're still testing us on how many bits a stupid floppy disk can hold, the last ten years of technological advancement have been able to improve radiation delivery, but not a simple thing like test results. Monte Carlo?
Click to expand...

This pretty much encapsulates the problem. We have taken so many standardized tests in our medical careers, we can pretty much look at a poorly written question and say, "I may or may not not know the answer to this question but I do know the 'correctness' of my answer has exactly 0% bearing on my ability to be a competent Radiation Oncologist."

Looking over recalls from Physics/Radbio last year and Clinical this year, I'm struck at how many questions have ambiguous answers. It sort of depends what the question writer was thinking at the time and what article he/she was reading to formulate the "correct" answer.

Since nobody cares about your percentile at this level, only if you pass, I think we can take such poor questions in stride. After all, for every poorly written question there's always a "what deficit do you get with a R CN XII deficit?" lurking around the corner. In the end it evens out.
 
Hey, how do we get our results in 3 weeks? Mail? Email? Through our PD?
 
You get them through snail mail of course! The address is whatever you have on record with the ABR.

Your first set of results will hopefully just say "Raidobiology: Pass, Physics: Pass."

A couple of weeks after this you will get your quartile ranks in each section.
 
oh snail mail? how progressive of us technologically inclined radonc folk. lol.

on the printout it says that we are supposed to be able to see our results that will be "posted on the PDB" in approximately 3 weeks.

not sure what the PDB is but i emailed the email addy saying i didnt' have any logon access. didn't see anything on the ABR site that gives any info about anything resembling this "PBD".
 
No, actually new this year...it said results will be from PDB...log in to the Personal Database or something on ABR website for test results (remember email address at end of test if you do not have your logon info)
 
mp2006 said:
No, actually new this year...it said results will be from PDB...log in to the Personal Database or something on ABR website for test results (remember email address at end of test if you do not have your logon info)
Click to expand...


Are you sure this wasn't a generic thing?

I want to weigh in re: physics -- completely INSANE. I thought i was way overprepared for physics and underprepared for bio and obviously NO amount of studying would have matter for physics. Not a single question on TPR/TMR/SAR that I wasted countless hours memorizing. And, to top it off, I screwed up negative exponents on the calculator and got couple of questions wrong. Wasn't even able to finish on time. Ugh. What a mess. Confident on maybe 40% of my answers at best... hope i pass.
 
I still don't know what a circulator is! The homogeneity correction question was a beast as well!! I agree with the sentiment - I could have studied for an entire other month, and still not have gotten any more questions...such minutia. The good news is, if we all felt this way, and the pass rate is >90%, we probably all did ok. We'll find out in 3 (?!) weeks.
 
In July 2009 the ABR transitioned the Radiation Oncology residents to an online system called the ABR Personal Database (PDB). The ABR PDB allows residents to register online and update their contact information. Last year the ABR began posting exam results to PDB, allowing residents to view their results online. In addition, once residents become board certified this same account is used for diplomates participating in the Maintenance of Certification (MOC) process.

(from ABR)
 
I tried to create an account on the ABR website for this PDB whatever, but you need your ABR ID as well as a "confirmation number." Anyone had any luck creating their account? I also sent them an email.

Thanks for the explanation about what all this means - I don't remember getting any correspondence from the ABR about anything related to the PDB, so it made no sense when that message appeared at the end of the exam.
 
oh i should have posted. i sent them an email yesterday and got a reply saying they'd be sending out login info sometime within the next week.
 
PDB login emails went out ..... no results yet but :scared: nonetheless
 
Right there with you. OMG, I hope I passed that stupid test!!!! 😱
 
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