Course Description
Radiation Physics I covers the physics of diagnostic imaging — the analysis and synthesis of energy and matter and the relationship between them. Students study atomic structure and the components required for the production of x-radiation, examine the components of imaging systems together with the tests and procedures used to evaluate them, and address the state and federal regulations governing radiation-producing equipment. Basic pharmacology is incorporated at several Florida institutions, including Daytona State.
Within the SCNS taxonomy, RTE is the Radiologic Technology prefix. RTE2613 is a 2-credit lecture course in the second year of the associate-degree radiography curriculum, and it is the prerequisite for RTE2623 Radiation Physics II. It appears at approximately five Florida institutions.
Physics is the course radiography students most often fear and most often underestimate the payoff of. The reason it is required is not academic: a radiographer who understands why kilovoltage changes subject contrast, why milliampere-seconds changes receptor exposure, and how scatter is produced is a radiographer who can fix a bad image and lower a patient's dose. One who has memorized technique charts cannot.
⚠ Not every Florida institution splits physics into two courses
Daytona State divides the subject into RTE2613 Radiation Physics I (2 credits) and RTE2623 Radiation Physics II. Other Florida institutions cover comparable content in a single larger course, or distribute it across exposure and equipment courses under entirely different numbers — Valencia's RTE sequence, for example, carries no RTE2613 at all and handles the material within its Principles of Radiography I/II/III series.
This matters for two reasons. First, this course also circulates under the inventory title "Radiologic Physics," which does not signal that it is only the first half. Second, a transfer student who completed a single comprehensive physics course elsewhere may find it maps to neither number cleanly. Match on the number and the catalog description, and expect the roman numeral to be local.
Learning Outcomes
Required Outcomes
- Describe atomic structure — nucleus, electron shells, binding energy — and explain ionization.
- Describe the electromagnetic spectrum and the properties of x-radiation within it.
- Explain the relationship between energy, frequency, and wavelength, and apply it quantitatively.
- Describe electricity, magnetism, and electromagnetic induction as they apply to x-ray equipment.
- Describe the components of the x-ray circuit: transformers, rectification, and the generator.
- Describe x-ray tube construction — cathode, anode, target, filtration, housing — and the function of each part.
- Explain the production of bremsstrahlung and characteristic radiation and interpret an x-ray emission spectrum.
- Explain how kilovoltage, milliamperage, exposure time, and filtration alter beam quantity and quality.
- Describe x-ray interactions with matter — photoelectric absorption, Compton scattering, coherent scattering — and their imaging and dose consequences.
- Explain attenuation, differential absorption, and the origin of subject contrast.
- Describe the production, effect, and control of scatter radiation, including grids and beam restriction.
- Describe the components of digital imaging systems and the tests used to evaluate them.
- Describe quality control testing of radiographic equipment and interpret the results.
- Explain x-ray tube rating charts, heat units, and anode heat capacity, and apply them to protect the tube.
- Describe the federal and Florida regulatory requirements governing radiation-producing equipment.
Optional Outcomes
- Describe fluoroscopic equipment, image intensification, and flat-panel fluoroscopy.
- Describe automatic exposure control and its failure modes.
- Describe the physical principles underlying CT, MRI, and other advanced modalities at an introductory level.
- Describe radiation detection and measurement instrumentation and units.
- Describe basic pharmacology relevant to imaging, including contrast agents and emergency drugs.
Major Topics
Required Topics
- Structure of matter: atoms, isotopes, binding energy, ionization
- Energy, the electromagnetic spectrum, and the properties of x-rays
- Electrostatics, electrodynamics, magnetism, and electromagnetic induction
- Transformers, rectification, and x-ray generators
- X-ray tube construction and the line focus principle
- Bremsstrahlung and characteristic radiation; the emission spectrum
- Beam quantity and quality; kVp, mAs, filtration, and the heel effect
- X-ray interactions with matter and differential absorption
- Attenuation, subject contrast, and scatter production
- Beam restriction, grids, and scatter control
- Digital image receptors and image acquisition
- Quality control testing and equipment evaluation
- Tube rating charts, heat units, and tube preservation
- Federal equipment standards and Florida radiation control regulation
- Introductory pharmacology for imaging (where included)
Optional Topics
- Fluoroscopy and image intensification
- Automatic exposure control
- Physical principles of CT and MRI
- Radiation detection instrumentation and units of measurement
- Mobile and surgical equipment
Resources & Tools
- Radiologic Science for Technologists: Physics, Biology, and Protection (Bushong) — the dominant text in this subject and effectively the standard reference for the ARRT physics domain.
- Principles of Radiographic Imaging (Carlton, Adler) — commonly used alongside for imaging principles.
- ARRT Radiography content specifications — the physics and equipment domains map directly onto this course.
- Florida Department of Health, Bureau of Radiation Control — the state regulator for radiation-producing machines; its rules under Chapter 64E-5, F.A.C. are the operative Florida requirements.
- NCRP reports and FDA CDRH equipment performance standards (21 CFR 1020) for the federal side.
- AAPM (aapm.org) — medical physics reports and quality control protocols, freely available.
- Laboratory equipment where QC is demonstrated: dosimeters, test tools, phantoms, and the department's own QC logs.
- Manufacturer tube rating charts and heat unit calculators.
Career Pathways
- Registered radiologic technologist, ARRT(R) — the primary destination.
- Quality control / quality management technologist — the role that grows most directly out of this course.
- CT, MRI, mammography, and interventional technologist — post-primary ARRT certifications where physics knowledge is a genuine differentiator.
- Applications specialist and field service liaison — equipment vendors hire technologists who understand the physics to train and support clinical users.
- Radiation safety officer support and dosimetry — hospital radiation safety programs.
- Medical physics assistant and, with further degrees, medical physics itself — a long path, but this course is the first step on it.
- Program faculty — physics instructors are the hardest position for Florida radiography programs to fill, which makes the specialization unusually marketable.
- SOC code 29-2034 Radiologic Technologists and Technicians.
Special Information
⚠ This is the highest-failure course in the radiography curriculum — and the reason is predictable
Radiation physics has the reputation of being the hardest course in the program, and the pattern behind the failures is consistent: students arrive expecting to memorize and discover the examinations require them to reason about relationships. Knowing that increasing kVp increases penetration is memorization. Predicting what happens to receptor exposure, subject contrast, patient dose, and scatter when kVp increases and mAs is halved is the actual skill, and it is what both the course and the ARRT examination test.
Two things reliably help. Work problems rather than reread notes — the relationships only become intuitive through repetition. And connect every concept to something visible in clinic: the grid that removes scatter, the collimator that reduces it, the technique chart that encodes the tradeoff. Students who make that connection stop finding physics abstract, and it is also the point at which they start producing better images.
⚠ Dose reduction is a professional obligation, not a preference — and digital imaging made it harder
The principle taught here is ALARA — as low as reasonably achievable — and the practical levers are collimation, appropriate technique, shielding, distance, and avoiding repeats. Three points worth carrying:
- Collimation is the single most effective dose reduction the radiographer directly controls, and it improves contrast at the same time. It costs nothing and is skipped constantly.
- Digital receptors will produce an acceptable-looking image over a wide range of exposures, which broke the feedback loop that film provided. Overexposure no longer looks dark — it looks fine, and the patient absorbed the dose anyway. This is called exposure creep, and it is why exposure indicators must be monitored rather than trusted to the image's appearance. This is one of the most consequential changes in the profession's recent history and is under-taught relative to its importance.
- Repeat analysis is a required quality metric, and — the same lesson that appears elsewhere in this repository — a measure used to evaluate individuals stops measuring what it did, because repeats get hidden. Its value is diagnostic, not punitive.
Florida regulatory context
Radiation-producing equipment in Florida is regulated by the Florida Department of Health, Bureau of Radiation Control, under Chapter 404, F.S. and Rule Chapter 64E-5, F.A.C. — registration of machines, shielding plan review, periodic inspection, and personnel monitoring. Radiologic technologists themselves are separately licensed under Chapter 468, Part IV, F.S. The distinction matters in practice: the machine is registered and inspected under one framework, the operator is certified under another, and a facility can be compliant on one and not the other. Both frameworks are amended periodically; verify current requirements with the Department of Health.
Course format, credits, and contact hours
RTE2613 is a lecture course carrying 2 credits at Daytona State, offered in summer. The 32 contact hours reported here is derived from that credit value at the 16-hours-per-credit convention this repository's DSC-family RTE courses use consistently (RTE2061 at 1 credit / 16 hours; RTE2385C at 3 credits / 48 hours), and matches Valencia's 2-credit RTE2385 at 2 lecture hours per week. Institutions that cover the physics in a single larger course will report materially different values — confirm on the syllabus.
Expect calculation-heavy examinations, emission spectrum interpretation, and problem sets on tube rating and heat units. Where basic pharmacology is folded in, it is typically assessed separately from the physics content.
How Florida course levels affect transfer
The first digit of an SCNS number denotes the year of offering, not transferability. Courses at the 1000 and 2000 levels transfer transparently between Florida public institutions, and 3000 to 4000 is unproblematic since both are upper division. The boundary that actually matters is 2000 to 3000, where lower-division credit generally cannot satisfy an upper-division requirement — which matters a great deal in radiography, because several Florida institutions now offer a B.S. completion track with 3000- and 4000-level RTE courses that associate-level coursework cannot substitute for.
One caveat overrides all of it in practice: radiography programs are JRCERT-accredited, lock-step cohorts with sequenced clinical placements, and they accept transfer into the professional sequence rarely and case by case. Expect to repeat coursework when moving between programs, and get any transfer evaluation in writing first.