lattice therapy

[RickyScott]

Does anyone know much about lattice therapy at Wash U for pancreas/gi? think this is such a cool idea. In past, I have tried to use IMRT to mimick grid on several large sarcomas/tumors. This is the kind of research the field needs to be doing, not 5 vs 15 treatments for breast cancer.

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[thecarbonionangle]

GRID therapy has been done at select places for many years.

 

[RickyScott]

GRID therapy has been done at select places for many years.

but usually for large masses?

 

[thecarbonionangle]

but usually for large masses?

yes it works great for large bulky tumours. The rationale with GRID/SFRT, is to give high dose (10-15Gy in 1 fx) to promote oxygenation and then follow it with more standard fractionation. You can use physical GRID blocks which are quite heavy and have some limitations for deep tumours because of single beam/2 beam dosimetry or you can do virtual GRID with IMRT/tomotherapy.

some discussion/info here:

Spatially fractionated radiation therapy: History, present and the future - PMC

www.ncbi.nlm.nih.gov

GRID Therapy - .decimal

Grid radiation therapy, using the megavoltage X-ray beam, has been proven to be an effective method for management of large and bulky malignant tumors. This treatment modality is also known as Spatially Fractionated Radiation Therapy (SFRT). In this treatment technique a grid block converted...

dotdecimal.com

 

[scarbrtj]

Mo Mohiuddin, GRID allfather... so many crazy ideas from rad onc past become fashionable in future! GRID literally negates a pithism I am fond of: the goal is the tumor-within-the-field technique, not the field-within-the-tumor.
EDIT: I have in mind's eye occasionally seen the temporality of FLASH if modeled at the cell's eye view ("dose mottling") as GRID at spur/blob size ranges.

(Is Mo's son also now a rad onc?)

 

[RickyScott]

or.

(Is Mo's son also now a rad onc?)

Mohiudden brought technique over from england where it was used to deliver large doses to deeper tumor in pre-MV era.
yes he is, and also smart, and one of the many talented young docs who left maryland in the past.

 

[evilbooyaa]

I've heard about this only for re-irradiation cases where it is not safe to radiate the entirety of the tumor to prescription dose. Are people doing it in the upfront setting as well?

 

[thecarbonionangle]

I've heard about this only for re-irradiation cases where it is not safe to radiate the entirety of the tumor to prescription dose. Are people doing it in the upfront setting as well?

yes up front for H&N, GI, sarcoma, etc

 

[evilbooyaa]

just treat the whole thing..... especially in H&N and sarcoma. GI I could see some rationale with a big bulky HCC that you can't meet constraints on, or something.

Any (even retrospective) data suggesting we should be doing this at all 'routinely'?

 

[fiji128]

We did a fair amount of these in residency (15Gy x 1), mostly in the inpatient setting with large pelvic tumors and head and neck stuff. Not a huge fan. Basically about 50% of the patients we gave it to won't do well with any type of available treatment and are destined to die in a week or two and the other 50% probably would have been better served in the long run doing a real plan with dosimetry and DVHs and what not. But it does seem to have become more fashionable lately. Also, if you're inclined to do this always have your field off cord otherwise not too many other rules with it.

 

[Lamount]

Is this like micro-beams? I remember sitting next to a Avraham Dilmanian who had done some interesting work on animal models a few years back. I was always wondering if anything ever came of it.

 

[thecarbonionangle]

For those with questions about the technique here is further reading, retrospective, I am not aware of a larger trial in H&N in the past or ongoing, but I am of the opinion it is worth looking into, very interesting:

SAGE Journals: Your gateway to world-class research journals

Subscription and open access journals from SAGE Publishing, the world's leading independent academic publisher.

journals.sagepub.com

Clinical Outcomes of Spatially Fractionated GRID Radiotherapy in the Treatment of Bulky Tumors of the Head and Neck

Objectives The clinical outcomes of patients treated with spatially fractionated GRID radiotherapy (SFGRT) for bulky tumors of the head and neck at a single institution were evaluated retrospectively. Endpoints of interest included tumor response, symptom improvement, treatment tolerance, and...

www.cureus.com

abstract 2831: https://www.redjournal.org/article/S0360-3016(15)02130-6/pdf

more of a clinically relevant physics discussion: Error - Cookies Turned Off

Why we should give spatially fractionated radiation therapy (GRID) a second look—especially in nasopharyngeal carcinoma - Poh - Annals of Nasopharynx Cancer

https://www.ctro.science/article/S2405-6308(19)30104-1/pdf

https://pubs.rsna.org/doi/abs/10.1148/67.5.757

high dose bystander effect? https://pureadmin.qub.ac.uk/ws/portalfiles/portal/30628333/high_dose.pdf

 

[thecarbonionangle]

Is this like micro-beams? I remember sitting next to a Avraham Dilmanian who had done some interesting work on animal models a few years back. I was always wondering if anything ever came of it.

the beams are not microscopic in GRID

 

[fiji128]

Is this like micro-beams? I remember sitting next to a Avraham Dilmanian who had done some interesting work on animal models a few years back. I was always wondering if anything ever came of it.

If you look at the physical grid you would mount in the gantry head it is basically just a bunch of evenly spaced holes. Probably about 50% solid beam blocking metal and 50% open, kinda like a slice of swiss cheese. Now this can also be done by manipulating mlc to get the same effect.

 

[thecarbonionangle]

Another term for it is "virtual brachytherapy". The holes in the blocks are spaced out like interstitial brachytherapy hallow needles.