CRYOPROBE
TECHNOLOGY EXPLAINED
The argon-gas cryoprobe is the engineering core of modern cryoablation — a needle-thin device that reaches –150°C at its tip, generates a precisely shaped ice-ball, and enables multi-probe ablation of tumours far larger than any single needle could treat.
analyticsAt a Glance
- check_circleArgon gas expands through the probe tip via the Joule-Thomson effect, cooling tissue to –150°C
- check_circleHelium gas is used for the active thaw phase — warming the probe tip to facilitate safe removal
- check_circleProbes range from 1.47 mm to 3.8 mm diameter — chosen based on target lesion size and anatomy
- check_circleMulti-probe arrays allow simultaneous ablation of irregular or large (>3 cm) tumours with a single interlocked ice-ball
How Argon-Gas Cryoprobes Work
The physics behind cryoablation is elegant. High-pressure argon gas — stored in a tank connected to the probe console — expands rapidly through a small orifice at the probe tip. This expansion, described by the Joule-Thomson effect, absorbs heat from the surrounding tissue and drops the probe tip temperature to –150°C within seconds of activation.
“The Joule-Thomson effect is the same physics that makes an aerosol can feel cold when you spray it — scaled up and precisely controlled to freeze a tumour from within.”
Active Freeze: Argon Gas
High-pressure argon (250–300 psi) flows down the probe shaft, expands at the distal tip, and drops to –150°C via the Joule-Thomson effect. The ice-ball grows outward from the probe tip at approximately 1 mm per minute — radiographically visible on CT as a hypodense zone with a sharply defined margin.
Active Thaw: Helium Gas
After the freeze cycle, helium gas is switched into the system. Helium undergoes the reverse Joule-Thomson effect — it warms as it expands — rapidly thawing the probe tip from –150°C to approximately +40°C. This facilitates safe probe removal from frozen tissue without fracture or haemorrhage.
Cryoprobe Sizes and Clinical Applications
Probe diameter determines both the size of the ice-ball that can be generated and the tissue trauma of insertion. Selection is matched to the target lesion and anatomy.
| Probe Diameter | Ice-Ball Size (approx) | Insertion Path | Typical Clinical Use |
|---|---|---|---|
| 1.47 mm (17G) | 2.0–2.5 cm | Fine-needle — same as biopsy needle | Breast fibroadenoma; superficial soft tissue; paediatric cases |
| 2.0 mm (14G) | 2.5–3.0 cm | Small-bore percutaneous | Renal cortical tumours ≤2 cm; lung nodules |
| 2.4 mm (12G) | 3.0–3.5 cm | Standard percutaneous probe | Most common: liver, kidney, bone, lung (standard lesion size) |
| 3.4 mm (10G) | 3.5–4.5 cm | Larger bore — local anaesthetic needed | Larger liver and renal tumours; pelvic lesions |
| 3.8 mm (8G) | 4.0–5.0 cm | Intraoperative / laparoscopic use | Open or laparoscopic liver cryoablation; intraoperative targeting |
Multi-Probe Arrays: How Larger Tumours Are Treated
A single cryoprobe generates an ice-ball of approximately 3–5 cm. Tumours larger than this — or those with irregular shapes — require multiple probes placed simultaneously to create an interlocked, confluent ice-ball that covers the entire target volume.
- 1
Pre-Procedure Planning
The operator uses 3D imaging (CT volumetrics or dedicated ablation planning software) to calculate the number, diameter, and spacing of probes needed to produce an ice-ball that fully encompasses the tumour plus a 5 mm margin.
- 2
Probe Spacing Design
Probes are typically spaced 1.5–2.0 cm apart. Ice-balls from adjacent probes merge and interlock — the merged zone reaches the target temperature across the entire confluent volume rather than just at individual probe tips.
- 3
Simultaneous Multi-Probe Insertion
All probes are inserted in sequence under CT guidance before any freeze is initiated. This ensures all probes are in the correct position relative to each other before the geometry of the ice-ball is determined.
- 4
Synchronised Freeze
All probes are activated simultaneously by the console. The synchronised freeze creates a uniform, merged ice-ball — non-simultaneous freezing causes probe displacement as the first ice-ball deforms surrounding tissue.
- 5
Ice-Ball Confirmation
Intraprocedural CT confirms the confluent ice-ball covers the full tumour volume with an adequate margin. Adjustments — advancing or withdrawing individual probes — can be made during the thaw phase before the second freeze.
- 6
Simultaneous Thaw and Removal
Helium is activated on all probes simultaneously to thaw the entire ice-ball before probe removal. Removing individual probes while others remain frozen can cause mechanical tissue injury.
Major Cryoablation Systems in Clinical Use
Several commercial cryoablation systems are used globally. The systems differ in console design, probe compatibility, gas consumption, and intraprocedural monitoring features.
Galil Medical / BTG IcePearl and SeedNet (Becton Dickinson)
The most widely used cryoablation system globally. Offers the broadest probe range (1.47 mm to 3.8 mm), compatible with up to 25 simultaneous probes, and provides real-time temperature monitoring through integrated thermosensors. Used at most high-volume interventional oncology centres in China.
IceCure Medical ProSense
A liquid nitrogen-based system (rather than argon gas) using a disposable cartridge delivery mechanism. The ProSense system is designed for in-office use with an emphasis on breast fibroadenoma and small peripheral tumours. Its disposable cartridge eliminates the need for compressed argon gas tanks at the point of care.
Endocare (HealthTronics) Cryocare CS
A well-established argon-helium system with a long track record in renal cryoablation and prostate cryotherapy. The Cryocare system uses vacuum-insulated probe shafts to minimise shaft-freeze artefact on imaging, improving ice-ball visualisation at the probe tip-to-shaft transition zone.
Key Technology Parameters
Reference figures for operators and patients who want to understand the engineering behind what they are experiencing.
- –150°CProbe tip minimum temperatureAchieved via argon gas Joule-Thomson expansion; the tumour periphery is exposed to –40°C or below — the lethal threshold for cancer cells.
- +40°CActive thaw temperature (helium)Helium expansion warms the probe tip to approximately +40°C during active thaw, enabling safe removal from thawing tissue.
- 1–3 minTime to reach target freeze temperatureFrom activation, modern cryoprobes reach –40°C at the probe tip within 60–90 seconds; the ice-ball reaches target dimensions in 8–15 minutes.
- 25Max simultaneous probes (Galil system)Up to 25 probes can be activated simultaneously by the Galil console, enabling treatment of very large or multi-focal lesions in a single session.
More from the Cryoablation Therapy Resource Library
Continue exploring — from the patient procedure experience to clinical applications and immunotherapy combinations.
- Cryoablation Therapy — Complete Treatment Guide
- Cryoablation vs RFA vs MWA: Which Ablation Is Right for You?
- What to Expect During and After Cryoablation
- Complications of Cryoablation: Risk Profile and Management
- Cryoimmunotherapy: Combining Cryoablation with Checkpoint Inhibitors
- The Abscopal Effect: Can Cryoablation Trigger a Systemic Response?
Frequently Asked Questions
Technical questions patients and referring oncologists commonly ask about cryoprobe systems.
Technology Questions
Is argon gas safe to use inside the body?
Yes. Argon is an inert noble gas — it does not react chemically with tissue. The gas remains entirely within the sealed probe shaft and never contacts the patient's tissue directly. The cooling effect is transmitted through the probe wall via conduction. In the extremely rare event of a probe fracture (a reported but very uncommon equipment failure), argon gas is non-toxic and rapidly absorbed.
How does the doctor know the tumour has been fully frozen?
The ice-ball generated by the cryoprobes appears as a sharply defined hypodense (dark) zone on CT imaging — it is directly visible and distinguishable from unfrozen tissue. The operator performs intraprocedural CT scans during the freeze cycle to confirm the ice-ball margin has extended at least 5–10 mm beyond the tumour boundary. Optional thermosensors placed adjacent to critical structures provide real-time temperature data to confirm lethal temperatures have been reached throughout the target zone.
What happens to the probe entry hole after the procedure?
The probe creates a track through tissue of 1.5–3.8 mm depending on the probe size used. No sutures are required — the track is sealed either by the helium thaw warming the tissue, or by a tract-freeze protocol that ablates the entry channel as the probe is withdrawn. The skin entry is covered with a small adhesive dressing. There is no open wound to manage at home.
How CancerFax Helps
CancerFax is a specialist cancer access and patient-navigation platform. We help patients and families understand their options, organise medical records, coordinate hospital communication, and support cross-border treatment planning where appropriate.
We help collect and organise reports, scans, pathology, biomarker results, and treatment history for structured case review.
We communicate with hospitals or trial teams to assess whether a case may be suitable for further screening.
We support appointment coordination, document submission, translation, and direct communication with international departments.
For international patients, we help with practical coordination — travel planning, hospital admission guidance, and local support.
If this option is not suitable, we help explore other relevant treatments, clinical trials, or advanced care pathways.
From inquiry through to follow-up, our coordinators provide a single point of contact for the family.
CancerFax does not guarantee treatment access, eligibility, or clinical outcome. Our role is to help patients access accurate information, structured review, and appropriate specialist pathways.
Ask About Cryoablation Technology at Your Centre
CancerFax partners with centres in China and India that use modern argon-gas cryoablation systems. We can share information about the equipment and operator experience at each centre before you decide where to travel for treatment.
This content is for informational purposes only and does not constitute medical advice. Always consult a qualified oncologist before making treatment decisions.