Taking the CMD boards in August and trying to calibrate how much time I actually need. I've been in clinical dosimetry for 3 years so the treatment planning and isodose content feels like second nature, but the radiobiology and physics foundations sections are where I'm losing points on practice exams. Currently sitting around 63% on physics.
I'm putting in roughly 1 hour on weekdays after shifts and maybe 4 hours on weekends — about 9–10 hours a week. At that pace I have maybe 60 hours before exam day, and I'm not sure that's enough. Most people I've talked to said they did 80–120 hours total, but a lot of those folks came in with weaker clinical backgrounds than mine.
The AAMD study guide is my primary resource. I've also been working through old Radiological Physics Center benchmark problems for the physics sections. If anyone's gone through the CMD recently, I'd love to know whether the treatment planning simulation questions are more scenario-based or calculation-heavy on the current version.
I sat for CMD in 2024 and did about 95 hours of prep over 3 months. The physics section was the hardest part for me too — specifically inverse square law applications and beam modification factors. Grinding calculation problems daily helped more than re-reading theory ever did.
The current exam is more scenario-based than calculation-heavy from what I saw last fall. They give you a clinical situation and ask you to identify what's wrong or what the next step is. Less plugging numbers, more clinical reasoning.
With 3 years of clinical experience you're probably underestimating yourself on the planning sections. Where people consistently struggle is radiation protection and regulatory content — that stuff doesn't come up in daily work. Don't let that module slip.
I used Khan Academy physics refreshers alongside the AAMD materials and it helped a lot for the foundational concepts. Some radiobiology topics make more sense explained visually rather than just reading dense text.
Honestly I almost bailed around week 6. The radiobiology stuff felt impossible and I kept bombing the decay equations on every practice set. What actually helped me turn it around was drilling individual weak spots instead of doing full-length mocks -- I found some free cmd treatment planning dosimetry questions that let me isolate exactly where I was losing points rather than just grinding through stuff I already knew. That was probably the shift that saved me.
For context I had about 2.5 years clinical when I sat and I'd say I put in 90-100 hours over 10 weeks. With 3 years you're probably closer to ready than you think on the planning side -- don't waste time there. Pour everything into physics foundations for the last month and you'll be surprised how fast it clicks. You've got this.
Honestly, I was in a similar spot — three years of clinical experience meant the treatment planning stuff didn't scare me, but radiobiology and physics foundations humbled me fast. I studied part-time for about four months, usually 45 minutes to an hour on weeknights after the kids were in bed and maybe two hours on Sunday mornings. Didn't try to cram. Slow and steady actually worked better for the theory-heavy stuff because it gave things time to stick.
What helped me most was drilling targeted practice questions instead of just re-reading textbooks. I used a mix of resources but kept coming back to free cmd treatment planning dosimetry questions to stay sharp on the content I already knew while I pushed harder on the weak areas. You'll feel ready when you stop second-guessing the physics reasoning and start trusting your process — for me that clicked around week 14. August is totally doable if you start locking in a routine now.
I'll be honest, I almost bailed on this exam twice. I was three months in, drowning in radiobiology after 8+ years of clinical work, and my practice scores were stuck in the low 60s no matter what I did. I remember thinking maybe I just wasn't a test person. What finally worked wasn't more hours, it was different hours. I stopped rereading Khan and started drilling questions daily, then spending twice as long on the ones I missed. For me that was about 250 total hours over 4 months, but honestly the last 100 mattered way more than the first 150.
Since your planning knowledge is solid, don't sleep on the stuff nobody studies for. Ethics and legal questions felt like free points once I actually prepped them, and I'd skipped that section entirely until a month out. I used the cmd professional ethics legal compliance practice test a few times and it was an easy score bump. You've got the hard part down already. The physics will come with reps, it's a grind but it does click eventually. I passed with room to spare and I genuinely didn't believe that was possible in month three.