Maharashtra HSC Radiology Technician (Vocational) common mistakes
Maharashtra HSC Radiology Technician (Vocational) · Understand the traps and how to avoid them.
Quoting exposure factors as fixed kVp/mAs numbers for a named projection (for example 'AP knee = 60 kVp, 10 mAs') without stating that the value depends on film–screen speed class, grid ratio, SID and patient thickness.
Candidates memorise a single chart from one textbook or their placement department and treat it as universal, because the exam syllabus lists 'standard exposure factors' as a topic and revision notes often present one table without its assumptions.
What to do instead
Always attach the conditions when you give a factor: state the SID, the grid (for example 8:1, 100 cm), the receptor type and the patient size, then explain the direction of change (thicker part or higher grid ratio means more mAs; higher kVp means less mAs for the same receptor dose). If a question asks for a single number, give the number but add the assumptions in the same sentence.
Describing the purpose of the anode disc rotation or the focal spot as 'to make the image sharper' only, without linking it to heat dissipation over a larger focal track area and the resulting small effective focal spot.
X-ray tube questions are answered from a memorised phrase rather than from the physical chain from electron beam to focal track to heat capacity, so the answer sounds correct but misses the marking points on thermal rating and spatial resolution.
What to do instead
Answer in two steps every time: (1) rotation spreads electron bombardment over a circular track, raising heat capacity and permitting a small focal spot; (2) the small focal spot reduces geometric unsharpness because penumbra depends on focal spot size and object-to-receptor distance. Add the formula for penumbra so the link is explicit.
On positioning questions, naming the projection and the patient position but omitting the centring point, the direction and angle of the central ray, and the cassette placement relative to the part.
Candidates learn positioning from labelled images and remember the visual appearance of the radiograph rather than the written instructions, so under exam pressure they describe what the image looks like instead of what the radiographer must do.
What to do instead
Use a fixed four-part template for every positioning answer: patient position and part rotation, cassette position and size, centring point on the patient surface, and central ray direction and angle with SID. Rehearse writing five common projections (PA chest, AP/oblique lumbar spine, DP foot, PA wrist, AP pelvis) in that template until it is automatic.
Treating a rotated or poorly collimated repeat radiograph as acceptable because 'the pathology is visible', and not identifying the specific acceptance criterion that was breached.
Placement experience often rewards speed, and candidates rarely see formal reject analysis, so they evaluate images by whether a diagnosis can be made rather than against criteria such as symmetry, inclusion of joint spaces, collimation margins and absence of artefact.
What to do instead
Before judging any image, list the criteria for that projection (for example, on a PA chest: medial ends of clavicles equidistant from spinous process, whole lung fields included, scapulae clear of lung fields, no rotation). Then state which criterion failed and what change would correct it. Practise this on ten images per week during placement.
Confusing spatial resolution, contrast resolution and noise, for example stating that a larger matrix always improves contrast resolution or that a smaller pixel improves contrast resolution.
The terms are taught together and sound interchangeable; candidates also mix up detector pixel size with display matrix size, so they cannot separate the sampling step from the display step.
What to do instead
Define each in one line before answering: spatial resolution is the ability to separate small high-contrast objects and depends on pixel size and focal spot blur; contrast resolution is the ability to distinguish small differences in attenuation and depends on receptor dynamic range and dose; noise is unwanted signal variation. Then check whether the question asks about detectability (contrast) or sharpness (spatial) and answer only that.
In darkroom and processing questions, describing the developer as 'making the image appear' without stating that it reduces exposed silver halide grains to metallic silver, and giving the same temperature for developer and fixer.
Processing is often learned as a sequence of tank names rather than as chemistry, and candidates who have only used digital systems have limited direct experience of manual processing.
What to do instead
Learn the chemistry as one sentence per stage: developer reduces exposed grains to black metallic silver; fixer dissolves unexposed silver halide and hardens the emulsion; washing removes residual chemicals; drying hardens the film. State the standard condition explicitly (developer around 20 degrees Celsius, fixer at or slightly below developer temperature) and note that time and temperature must be controlled together.
Calculating dose or shielding questions using the inverse square law or half-value layer formula without converting units, so centimetres are mixed with metres or milligray with gray, and the final answer is out by a factor of 10 or 100.
Candidates focus on the formula and skip the unit check, and the exam deliberately mixes units (mGy, Gy, mSv, cm, m) to test whether the candidate is paying attention to the physical quantity.
What to do instead
Adopt a three-line working habit: write the known values with units, convert to SI base or stated units in one line, then substitute. For inverse square law, always convert distances to the same unit before squaring. For half-value layer problems, count the number of layers and write the factor as (1/2)^n before calculating.
Answering a protection question with 'wear a lead apron' or 'use collimation' but omitting the three cardinal principles (time, distance, shielding), the difference between occupational and public dose limits, and the role of the ALARA principle in justification.
Protection is revised as a list of slogans, and candidates do not separate dose limits for radiation workers from those for members of the public or from diagnostic reference levels, which are not limits at all.
What to do instead
Structure every protection answer around justification, optimisation and dose limitation, then state the applicable limit category. Keep the numbers distinct in your notes: occupational whole-body limit, public limit, and the fact that diagnostic reference levels are advisory benchmarks for a procedure, not legal limits. Name the practical control for each principle (collimation, gonad shielding, distance from the tube, lead apron and thyroid shield, dose monitoring badge).
Describing a contrast study as 'give contrast and take films' without stating patient preparation, the route and volume of contrast, the timing of films, and the contraindications or emergency drugs available.
Contrast procedures are learned as a schedule of images rather than as a clinical procedure, so candidates omit the safety and timing elements that carry most of the marks.
What to do instead
For each study (for example barium meal, barium enema, intravenous urogram, hysterosalpingography, fistulogram) write a five-line plan: preparation, contrast medium and route, film sequence with timing, contraindications, and aftercare. Always mention the resuscitation trolley, emergency drugs and the need for a radiologist or clinician to be present for invasive studies.
In patient care and ethics scenarios, giving a general answer such as 'explain the procedure and be polite' without addressing consent, confidentiality, the patient's right to refuse, or the specific first-aid action for the emergency described.
These topics are treated as common sense rather than as examinable content, so candidates write reassuring prose instead of naming the legal or clinical step, and they confuse 'informed consent' with 'signing a form'.
What to do instead
Answer scenario questions with named steps: identify yourself and the procedure, explain benefits and risks in language the patient understands, confirm the patient can refuse, record consent, and maintain confidentiality by discussing the case only with those involved in care. For first aid, state the sequence (scene safety, check response and breathing, call for help, then the specific action such as positioning, oxygen, or control of bleeding) and name the equipment used.