rgs

Question 1

why RGS

Answer 1

Less morbidity
1.Guidance during surgery, direct access
2.No need of anatomical resection

Less recurrence
1. Intraoperative control, nothing left behind
2.Guidance during surgery, confirm targets

Question 2

RGS types by marking

Answer 2

with tracers using biochemistry
using physiology eg. SLNB based on lymphatic drain
directly eg. ROLL RSL

Question 3

RGS marking technology

Answer 3

Radioactive isotopes
Radiopharmaceuticals & seeds

Question 4

beta emitters

Answer 4

F-18 penetration <1.2mm
Ga-68 penetration <6 mm

Question 5

gamma emitters

Answer 5

I-125 half depth ~20 mm
Tc-99m half depth ~45 mm
PET-isotopes (511keV) half depth ~72 mm

Question 6

handheld pros cons

Answer 6

Pros:
- Highly flexible
- Intuitive use

Cons:
- Only accoustics + value

For gamma probes:
- Ideal for Tc-99m
- Suboptimal for PET isotopes

For beta probes:
- Low penetration, only for
PET isotopes

Question 7

RGS detecting technology

Answer 7

Handheld probes
Portable gamma cameras
Beta imagers
Freehand SPECT

Question 8

Portable gamma cameras pros cons

Answer 8

Pros:
- 2D image
- Control of resection
- High sensitivity

Contras:
- Image from outside
- Not for PET isotopes
- Low resolution

Question 9

beta imagers pros cons

Answer 9

Pros:
- 2D image
- High resolution
Cons:
- Only specimen imaging
- Only PET isotopes
- Low sensitivity

Question 10

Freehand SPECT pros cons

Answer 10

Pros:
- 3D image
- Incorporated navigation
- Distance measurement

Contras:
- Slow image acquisition
- Complex usability
- Not for PET isotopes