RadOnc Smart Review

This is Episode 6, Modeling Survival: Target Theory and L Q.In our last episode, we looked at how radiobiologists actually measure cell survival using clonogenic assays. These experiments generate dose-response data, typically plotted as cell survival curves. Today, we'll explore the mathematical models developed to describe and understand the characteristic shapes of these survival curves, focusing on the historical Target Theory and the current standard, the Linear-Quadratic model.

This is Episode 5, Measuring Survival: Clonogenic Assays.In our last episode, we explored the different ways cells can die after radiation – apoptosis, necrosis, mitotic catastrophe, and others. But in radiation oncology, the ultimate goal isn't just causing immediate cell death, it's preventing tumor cells from dividing and regrowing. Today, we'll focus on the "gold standard" methods used in radiobiology to measure this loss of reproductive capability, both in the lab dish and within living organisms.

Welcome back to Rad Onc Smart Review. This is Episode 4, Mechanisms of Cell Death & Response.Last time, we explored how radiation can cause major structural damage to chromosomes. Today, we're diving into the consequences of that damage, looking at the diverse ways cells respond when faced with radiation injury – focusing on the distinct pathways leading to cell death or dysfunction, including apoptosis, necrosis, mitotic catastrophe, autophagy, and senescence. Knowing how to differentiate these is key for understanding treatment response.

In our last episodes, we drilled down into how cells repair specific DNA lesions, like base damage, single-strand breaks, and those critical double-strand breaks via NHEJ and HR. Today, we're zooming out to look at the bigger picture: what happens when DNA breaks lead to large-scale damage visible at the chromosome level? We'll cover different types of chromosome aberrations caused by radiation, classifying them as lethal or potentially cancer-promoting, and link these concepts to human genetic syndromes caused by defects in DNA repair.

In our previous episode, we discussed how cells handle single strand breaks and how they perform a quick but potentially error filled patch up of double strand breaks using Non-Homologous End Joining, or NHE J. Today, we're diving into the cell's high fidelity repair system for double strand breaks: Homologous Recombination, or HR. We'll explore how it works, why it's so accurate, and highlight the crucial roles played by proteins like BRCA 1 and BRCA 2.

This is our final episode focused purely on calculations! We've journeyed from basic decay to complex Monitor Unit calculations. Today, we hit the advanced scenarios: What happens when the beam hits lung or bone? How do we compare radically different fractionation schemes biologically? How does modern brachytherapy dosimetry really work with TG 43? And finally, the essential math for keeping everyone safe from radiation. Today, we’re calculating radiological path length, BED and EQD 2, applying the TG 43 framework with Air Kerma Strength, and ensuring our shielding calculations meet regulatory limits.

Welcome back to Radiation Oncology Smart Review – Calculation Toolkit Episode 17C: Dose Divers and Electron Escapades. Last time, we calibrated our detectors and nailed Monitor Unit calculations for standard setups. Now, we follow the dose after it leaves the machine head. Today, we'll master transferring dose between different depths using Percent Depth Doses and Tissue Maximum Ratios, untangle the geometric puzzles of skin gaps for field matching, learn the simple scaling rules for field sizes, calculate equivalent squares, and dip our toes into the unique world of electron beam Monitor Unit calculations.

Welcome back to Radiation Oncology Smart Review – Episode 17 part B: Dosimetry Detectives and Chamber Charades. Last time, we tackled the ticking clocks of decay and permanent implants. Today, we put on our detective hats to investigate how we actually measure radiation and make sure the right dose goes to the right place. We’ll decode the secrets of ion chambers and their sneaky temperature-pressure dependence, master the Monitor Unit, or M U, calculations for both S A D and S S D setups – the absolute bedrock of clinical physics – figure out how dose changes with depth using P D Ds and T M Rs, and learn how linacs play geometric tricks with field sizes.

Welcome back to Radiation Oncology Smart Review – the targeted prep for your radiation oncology boards! I’m your guide, diving deep into the calculations that matter. This is Episode 17a of our Calculation Toolkit series, titled Radiation Oncology Calculations 1: Half-Lives and Seed Sleuths. Today we’ll master three bread-and-butter RAPHEX problem families: first, radioactive decay and time-activity puzzles, second, effective half-life mash-ups, and third, permanent implant total-dose questions. By the end you’ll know why lambda keeps physicists up at night, how to find the Goldilocks half-life combining body and physics, and how one sleepy iodine one twenty-five seed still manages to deliver its full punch over months.

This is Episode 2b, DNA Repair: Single-Strand Breaks& NHEJ.Last time, we delved into Base Excision Repair andNucleotide Excision Repair, the cell's tools for fixing damaged bases and bulkylesions. But ionizing radiation does more than just damage bases – itfrequently breaks the sugar-phosphate backbone of DNA. Today, we'll explore howcells handle single-strand breaks and introduce the first major pathway forrepairing the most critical radiation-induced lesion: the double-strand break,specifically focusing on the fast but potentially risky pathway called Non-HomologousEnd Joining, or NHEJ.