miscellaneous` Flashcards
irreversible cell changes
cellular death (necrosis) or changes that eventually become lethal to the cell (apoptosis)
what is apoptosis
programmed cell death
extravasation
accidental leakage of iv drugs into tissue either through the weak portion of the vein or because the needle punctured vein and infusion goes directly into surrounding tissue or because needle punctures the vein and the infusion goest directly into the surrounding tissue
most common cause of tissue damage
hypoxia
neoplasia definition
abnormal process that results in the formation of a neoplasm or tumour
4 phases of the dell cycle
G1,S,G2,M
what part of the cell cycle is radio resistant
S Phase, worst part of the cell cycle for XRT to be delivered
what part of the cel phase is radiosensitive
G2-M phase (Mp hase s when PMAT occurs)
free radical definition
highly reactive species with unpaired valance shell electron
ex: h2o = H + OH
direct ionization
occurs more often with _____
considered ____radiations
occurs more often wth densely ionizing XRT (protons alpha particles)
considered high LET XRT
fast electron DIRECTLY ionizes DNA molecule causing damage
indirect ionization
occurs more often when _____
occurs more often with sparsely ionizing XRT (xreays, gamma rays)
causes damage to the DNA molecule from splitting H20
\
RBE
relative biologic effectiveness
atio of biological effectiveness of one type of ionizing radiation relative to another, given the same amount of absorbed energy
stable abberation examples
- result in genetic mix ups leading to mutations but the cell remains viable
ex: translocations and inversion aberrations
unstable abberations examples
aberrations that kill the cell are unstable aberrations
ex: rings, dicentric,s anaphase bridges
most common endpoint for cells response to xrt
reproductive failure
what is interphase death
if death of the cell occurs due to XRT of the G1,G2 and S phase
cellular apoptosis has the involvement of what genes
P53 and BCL2
Most potent radiosensitizer
radio sensitizer enhances cells response to XRT
the most potent radio sensitizer is oxygen
what is OER
oxygen enhancement ratio
it compares the response of cells with radiation in the presence and absence of oxygen
what type of cells are considered to be radiosensitive (organs)
testes and bone marrow, skin
organs that are considered to be radioresistant
liver, muscle, brain and spinal cord
deterministic effects
when tissues have a threshold dose associated with a clinical response
phases from radiation syndromes
- prodromal phase: symptoms correlate to dose and can be go or neurological or both in nature within hrs of exposure
- latent phase: period where victim has no symptoms of exposure few days -3wks after exposure
- manifest ill stage: effects of exposure are evident and correlate with dose(3-5 wks after exposure)
how long does it take for death to occu hemapotic syndromer:
300-500cGy
500-100cgy
<300Cgy patient usually recovers in 3-6 dos
300-500cgY PATIENT DIES 4-6 WEEKS
500-1000Cgy occurs within 2 weeks
primary causes of death from hemapoteic syndrome
infection and hemorrhaging after destruction of bone marrow
at what dose does the GI syndrome occur
1000-10,000cgy
mean time to death for GI syndrome
3days-2 weeks
what causes the death in GI syndrome
bone marrow image leads to death as a result from infection , dehydration and electrolyte imbalance
3 radiation syndromes
hemapoetic syndrome, gastrointestinal syndrome and cerebrovascular syndrome
what dose does cerebrovascular syndrome occur at
doses >10,000Cgy
how long does it take for death to occur in cerebrovascular syndrome
days
what symptoms occur in the prodromal stage of cerebrovascular syndrome
nervousness, confusion, n&v, loss of consciousness and a burning sensation of the skin
what symptoms occur in the manifest illness stage of cerebrovascular syndrome
watery duahrrea, convulsions, coma and death
stage of gestation and effects of XRT
STAGE GROWTH RETARDATION /MENTAL RETARDATION
preimplantation none none
organogenesis temp v. high risk
fetal perm high risk
previous XRT can cause hat types of cancer
skin cancer, leukaemia, osteosarcoma, lung, breast and thyroid cancer
what type of leukemias does XRT not cause
CLL
4 R’S OF RADIOBIOLOGY
- repopulation
- redistribution
- Repir
- reoxygenation
hyperfractination and hypo fractionation
hyper: are radiation treatments given BID or TID
hypo: use of dose fractions that are higher than the typical fractionation dose of 2Gy
what does TD5/5 stand for
dose required for a minimal (5%) complication rate over 5 years
BED
biological effective dose
is a measure of the true biological dose delivered by a particular combination of dose per fraction and total dose to a particular tissue characterized by a specific α/β ratio
WHATS A SIGN VS A SYMPTOM
sign is an object of finding that can be seen by an examiner
a symptom is subjective indication of a disease or change in condition as perceived by a patient
paraneoplastci syndrome
collection of symptoms that result from substances or hormones produced by the tumour
normal temperature
oral ,rectal and axillary temperature acquisition methods
oral: 96.8-98.6F = 36-37 c
rectal: 99.6F (37,5C)
axillary: 97.6 F (36.4C)
normal range for pulse
60-100 bpm
normal range for respirations
12-18 breaths/ min
normal blood pressure values
systolic: 90-140mm Hg
diastolic: 60-80 mmHg
where is blood pressure taken (what artery?)
brachial artery
how much should the cuff be inflated by when taking blood presure
to 180-200 mmHg or around 30 mmHg above the point where the pulse dissapears
what tool takes blood pressure
sphygmomanometer
what is systolic vs diastolic pressure in terms of what is happen with the heart
systolic is when pressure in the blood vessels when the heart contracts
diastolic pressure is when is pressure in the blood vessels when the heart relaxes
sensitivity vs specificity
sensitivity: ability of a test to give a true positive result
specificity: ability of the test to get a true negative result
4 factors observed during the taking of the pulse
rate, rhythm, size and tension
US uses _____ frequency sound waves
high
ionizing radiation and MRI
unlike other diagnostic imaging MRI does NOT use ionizing radiation
MRI is better for imaging _____ and CT is much better for imaging ______
MRI : soft tissue
CT: bone
normal range for WBC
5,000-10,000MM 3
Normal range for RBC
3.9-5.4 million mm3
normal range for hemoglobin
12-16g/dL
normal hematocrit levels
37-47%
normal neutrophil levels
42-72%
normal platelet levels
150,000-425,000mm3
basophil normal lvls
0-2%
normal eosinophil levels
0-4%
normal monocytwe levels
3-10%
normal lymphocyte levels
17-45%
exfoliative cytology means collecting tissue by:
a. needle Bx
b. scraping cells
c. incisional biopsy
d. excisional biopsy
B
cathode of a treatment machine
source of electrons - side of the X-ray tube
anode of a treatment machine
target that the electrons from the cathode hit + portion of the X-ray tube
parts of the cathode
filament and focusing cup
what is the filament made of usually
tungsten
what charge does the focusing cup have
-
what is the focusing cup
small oval depression embedded in the cathode, it helps direct e towards the anode in a straighter path
focal spot
part of the anode that the electrons from the cathode hit
x-ray photons are produced and begin to fan out divergently from here
thermpoionic emission
heat and the release of ions
radiwaves occur between what wavelength and frequency
wavelength of 10 exp 0 - 10 exp 6
frequency between 10 exp2 - 10 exp 8
microwaves occur between what wavelength and frequency
wavelength 10 exp -1 - 10 exp -4
frequency 10 exp 9- 10 exp 12
infrared occur between what wavelength and frequency
wavelength 10 exp -5 - 10 exp -6
frequency 10 exp 13- 10 exp 14
visible light occurs at what wavelength and frequency
w l 10 exp -6.5
fq 10 exp 14.5
UV light occurs at what fq and wl
wl 10 exp -7 - 10 exp -9
fq 10 exp 15- 10 exp 17
gamma x rays occurs at what fq and WL
WL - 10 exp -9 - 10 exp -16
FQ 10 exp 17- 10 exp 24
what % of target interaction is bremstralungh
75-80% target interaction is bremstralungh
WL and FQ of XRAY IMAGING
WL 10 exp -10 - 10 exp -11
FQ 10 exp 18 - 10 exp 19
MR imagine frequency and WL
WL 10 exp 0 - 10 exp2
FQ 10 exp 6- 10 exp 8
characteristic XRT
Created by direct interaction of cathode electrons with inner shell electrons of target material
principal and secondary interaction in X-ray production
principal = bremstralung secondary = characteristic radiation
ionization events in the ___ or ___ shell of tungsten ago do NOT produce characteristic X-rays
o an p shell
3 interactions in the diagnostic range
compton
coherent/ unmodified scattering
photoelectric effect
predominant interaction of the therapeutic range
compton
what is comtpon scattering
freed electron travels a very short distance before attaching to another atom
coherent scattering occurs at what energy levels
low energy levels <10kEV
COHERENT SCATTERING DEFINITION
results in a change in the incident photons direction but no change in energy there is not enough energy to eject an electron from its orbit t
what interaction has the capacity to produce a useful image on CT detectors
photoelectric effect
photoelectric effect definition
occurs when the incident photon penetrates deep into the atom and ejects inner shell electron from orbit
the more _____ in the nucleus of the atom the more likely an incident photon will be absorbed through photoelectric effect
protons
what interaction is responsible for radioactive contrast
photoelectric
which interaction results in the ejection of a k shell electrob
photoelectri
density in terms of imaging
is the darkness of the i,age
the relationship between distance and density follows ____
ISL