Image-Guided Radiation Therapy (IGRT)
Precision radiation therapy is the family of techniques that aim radiation at a tumour with tight margins, and image-guided radiation therapy (IGRT) is the part that checks the aim. Ever wondered how a beam stays on target when you breathe, or when your bladder fills? This page explains how IGRT works, who it suits, and what a treatment day feels like.
Reviewed by Dr. P. Vijay Karan Reddy · Radiation Oncologist ·
Last updated October 2026
Precision radiation therapy uses detailed planning and technology to deliver radiation to a tumour while sparing healthy tissue. Image-guided radiation therapy (IGRT) is one form: scans taken before or during each session confirm the tumour's position, and the team corrects the setup if it has shifted. IGRT is painless and is often combined with techniques such as IMRT.
IGRT: The Part of Precision Radiation Therapy That Checks Its Aim
Picture your planning scan, taken with a comfortably full bladder. On treatment day your bladder holds a little more, and the prostate has drifted a few millimetres. IGRT adds a scan to every session, so the team sees that shift and corrects it before the beam turns on.
Older radiotherapy relied on skin marks and a plan made days earlier. But bodies change. Organs move, weight shifts, swelling comes and goes. As a 2024 Journal of the National Cancer Center editorial describes, radiation technology has moved from 2D and 3D conformal therapy to image guidance and intensity modulation. IGRT keeps the plan accurate on the day.
How IGRT Works in a Precision Radiation Therapy Procedure
IGRT adds a quick imaging check to the usual radiation routine. Here's what happens before the beam and while it's on.
IGRT by Cancer Type
He also uses it for lung, rectal, cervical and children's cancers, inoperable liver and pancreatic cancers, and transplant radiation.
Key Benefits of Precision Radiation Therapy With IGRT
Precision radiation therapy benefits vary by case. Tighter aim lowers risk but can't promise an outcome; your plan shows which apply.
IGRT vs. Other Radiation Techniques
IGRT is often confused with other techniques because they're used together. Here's how it differs in plain terms, and what each one adds.
IGRT vs. IMRT
IGRT is an add-on: imaging that checks the tumour's position before and during treatment. IMRT is dose shaping, fitting the radiation to the tumour's outline. Dr. Karan routinely combines them, as in every brain and head and neck cancer.
IGRT vs. conventional radiotherapy
Conventional radiotherapy lines you up with skin marks and a plan made on planning day. IGRT adds a scan on the machine each session, so small shifts get corrected. Dr. Karan's view: the tighter the margin, the more closely the tumour and body need watching, and daily imaging is the only way to go.
Preparing for IGRT Treatment
Most preparation happens at your planning visit. These are the four things to expect and to ask about.
Imaging and Tracking Methods Used in IGRT
The main image-guidance methods, by what they do. At Dr. Karan's centre, treatment runs on a TrueBeam STx linear accelerator with HyperArc. Imaging is kV and cone-beam CT, and breath-hold handles motion.
What a Treatment Day Looks Like
- 01
Check-in
You arrive at Apollo Hospital, Financial District, and the therapists confirm your name, plan and any preparation, like a full bladder.
- 02
Positioning
You lie on the couch while therapists fit your mask or cushion and line you up with the marks in the room.
- 03
Imaging
The machine's imaging arm rotates around you for a scan. Therapists review it and move the couch to correct any shift.
- 04
Radiation delivery
The beam delivers your planned dose from several angles. You'll feel nothing, and you can talk to the team through the intercom.
- 05
Finishing up
Therapists help you up and you head home. Most courses run on weekdays. IMRT and IGRT courses run 30 sessions for brain, 30 to 33 for head and neck, 25 for breast, cervical and rectal cancer, and 25 to 30 for prostate. With IGRT's higher precision, breast treatment can take 15 sessions and prostate 20 to 25. SBRT takes 3 to 5.
Precision Radiation Therapy Side Effects and Recovery
Does the extra imaging add risk? It adds a small dose the team plans for, and tighter targeting usually means fewer side effects.
Short-Term Effects
Tiredness and skin redness are common, plus effects tied to the area, like a sore throat for head and neck. They build over the weeks and ease with rest, skin care and medicines.
Long-Term Effects
Late effects depend on the organs near the tumour and the total dose. Precise targeting aims to lower them, and regular follow-up catches changes early, when they're easiest to treat.
Recovery Between Sessions
Most people keep to light routines. Rest, fluids and good food help. Dr. Karan sees you on the first day and then once every week, and assistant doctors monitor you daily, so problems are handled early. SRS and SBRT patients are reviewed daily. If something's urgent, you can contact him directly.
Considering IGRT? Get a Second Opinion First
Not sure image-guided treatment is the right fit, or whether your current plan uses it well? Send your scans and reports. Dr. Karan will review them, explain the options in plain terms, and tell you honestly what he'd recommend. Eleven years in radiation oncology go into every review.
What Happens After Treatment
Radiation keeps working for weeks after the last session. Here's the general roadmap, not a personal schedule.
Timing depends on the cancer treated, how it responds and how you recover. Your follow-up schedule is agreed with you before treatment ends, and can change.
Questions Patients Ask Us
It's an umbrella term for techniques that aim radiation tightly at a tumour while sparing healthy tissue. IGRT, IMRT, SBRT and radiosurgery all belong to it.
No, the scan and the beam are both painless. Any discomfort comes from lying still in position, not from the radiation.
It shows where the tumour and nearby organs sit today. The team can then correct any shift before the beam turns on.
You're on the table for 5 to 10 minutes, imaging included, depending on the technology. SRS or SBRT takes up to 15 minutes. Add about 30 to 45 minutes of waiting, and a daily visit comes to around 60 to 90 minutes.
They're tiny markers placed in or near the tumour, often in the prostate, so imaging can locate it precisely. Placement is a short procedure, and your team will explain what to expect.
Yes, a small amount, which the team includes in your plan. For most people, treating the right spot outweighs that added dose.
It depends on the technique, the number of sessions and the hospital, so there's no single price. At Dr. Karan's centre, a course of IMRT costs ₹2.5 lakh, IGRT ₹4.5 lakh, SRS ₹3 lakh and SBRT ₹4.5 lakh.
At major cancer centres, including Apollo Hospital, Financial District, Hyderabad. Dr. Karan delivers IGRT there with IMRT, and with SBRT where it suits the case.
They do different jobs, since protons are a type of radiation and IGRT is a way of aiming it. Dr. Karan says proton therapy can be used in essentially all indications where radiation is used; the issue is affordability.
In Dr. Karan's practice, nearly always. He uses it with IMRT for every brain, head and neck, breast and cervical cancer, and with SBRT for small lung, prostate, liver and pancreatic tumours.
Get a Clear Plan for Your Radiation Treatment
Send your scans and reports, and Dr. Karan will explain whether image-guided radiation fits your case and what each step involves. You'll get clear next steps, not a hard sell.
Written & reviewed by Dr. P. Vijay Karan Reddy ·
Radiation Oncologist · Last reviewed October 2026