# Brain metastasis velocity Brain metastasis velocity Status: LIVE Price: $0.005 USDC `GET /api/calc/bmv` HTML: https://magentlab.com/docs/bmv Markdown: https://magentlab.com/docs/bmv.md Not a medical device. Not a diagnosis, dose, or listing recommendation. ## What it computes Compute Farris 2017 brain metastasis velocity as new_brain_metastases / years_since_first_srs and report the published low, intermediate, or high group plus that group's median overall survival after initial distant brain failure. ## When to use When an agent already has the cumulative number of new brain metastases since first SRS and the years since first SRS, and must not floor BMV, use time since last SRS, or treat velocity as a diagnosis. ## When not to use - Not a medical device. magent does not count metastases on imaging or diagnose distant brain failure. - Farris 2017 BMV is new_brain_metastases / years_since_first_srs, rounded to 1 decimal. magent does not floor or round down BMV (that is NRG-BN009, not Farris). - Years since first SRS only. This tool does not use time since last SRS. - Not a diagnosis. Median OS is the published Farris 2017 group median after initial distant brain failure (low 12.4, intermediate 8.2, high 4.3 months). magent does not return confidence intervals or hazard ratios as scored outputs. ## Formula ``` bmv = new_brain_metastases / years_since_first_srs ``` ## Citation [Brain Metastasis Velocity: A Novel Prognostic Metric Predictive of Overall Survival and Freedom From Whole-Brain Radiation Therapy After Distant Brain Failure Following Upfront Radiosurgery Alone](https://doi.org/10.1016/j.ijrobp.2017.01.201) Farris M, McTyre ER, Cramer CK, et al. Int J Radiat Oncol Biol Phys. 2017 May 1;98(1):169-175 DOI: [10.1016/j.ijrobp.2017.01.201](https://doi.org/10.1016/j.ijrobp.2017.01.201) ## Worked example ### 3 new metastases 1 year after first SRS Given: `new_brain_metastases=3, years_since_first_srs=1` 1. bmv = 3 / 1 = 3.0 2. 3.0 < 4 is low; published median OS after initial distant brain failure is 12.4 months ### 14 new metastases 1 year after first SRS Given: `new_brain_metastases=14, years_since_first_srs=1` 1. bmv = 14 / 1 = 14.0 2. 14.0 > 13 is high; published median OS after initial distant brain failure is 4.3 months ## Also searched as - brain metastasis velocity - BMV - Farris BMV - distant brain failure velocity - new brain metastases per year - SRS brain metastasis velocity - brain mets velocity ## Parameters - `new_brain_metastases` (integer, required): Cumulative number of new brain metastases since first SRS (integer 0-200). Caller-assigned; magent does not count metastases on imaging. - `years_since_first_srs` (number, required): Years since first SRS (0.01-30; must be > 0). Farris 2017 uses time since first SRS, not time since last SRS. ## Bulk (POST) POST the same path with a JSON items array. The first item is the GET unit; each additional item is $0.002. Invalid items return HTTP 400 before settlement. Method: `POST /api/calc/bmv` Max items: 25 Price: unit_amount + extra_item_amount * (n - 1) (unit 5000 atomic, extra 2000 atomic) Status: PREVIEW - 1 to 25 items. Each item uses the same keys as the GET query parameters. - POST of 1 item costs the same as GET. Lists longer than 25: chunk into multiple POSTs. Extra items still execute; do not pad dummy rows. - The first invalid item fails the whole request (index in the 400 JSON). You are not charged. - HTTP 200 is {count, path, items}. Each items[i] is the GET 200 body for that row. - Catalog misses (empty matches, found=false) stay paid 200s inside that slot. - x402 resource URL is this path plus n and body_sha256. Browsers that prefer text/html get the same paywall as GET; Pay retries POST with the same items. Example request: ```json { "items": [ { "new_brain_metastases": "3", "years_since_first_srs": "1" }, { "new_brain_metastases": "3", "years_since_first_srs": "1" } ] } ``` Human paywall (two-item fixture): https://api.magentlab.com/paywall/bulk/bmv Example 200: ```json { "count": 2, "path": "/api/calc/bmv", "items": [ { "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.", "citation": { "authors": "Farris M, McTyre ER, Cramer CK, et al.", "doi": "10.1016/j.ijrobp.2017.01.201", "id": "farris-2017", "pmid": "28586952", "source": "Int J Radiat Oncol Biol Phys. 2017 May 1;98(1):169-175", "title": "Brain Metastasis Velocity: A Novel Prognostic Metric Predictive of Overall Survival and Freedom From Whole-Brain Radiation Therapy After Distant Brain Failure Following Upfront Radiosurgery Alone" }, "formula": "bmv", "formula_expression": "bmv = new_brain_metastases / years_since_first_srs", "risk_group": "low", "bmv": 3.0, "median_os_months": 12.4, "new_brain_metastases": 3, "years_since_first_srs": 1.0 }, { "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.", "citation": { "authors": "Farris M, McTyre ER, Cramer CK, et al.", "doi": "10.1016/j.ijrobp.2017.01.201", "id": "farris-2017", "pmid": "28586952", "source": "Int J Radiat Oncol Biol Phys. 2017 May 1;98(1):169-175", "title": "Brain Metastasis Velocity: A Novel Prognostic Metric Predictive of Overall Survival and Freedom From Whole-Brain Radiation Therapy After Distant Brain Failure Following Upfront Radiosurgery Alone" }, "formula": "bmv", "formula_expression": "bmv = new_brain_metastases / years_since_first_srs", "risk_group": "low", "bmv": 3.0, "median_os_months": 12.4, "new_brain_metastases": 3, "years_since_first_srs": 1.0 } ] } ``` ## Response fields - `formula` (string): bmv - `formula_expression` (string): Exact expression used - `new_brain_metastases` (integer): Cumulative new brain metastases since first SRS used - `years_since_first_srs` (number): Years since first SRS used - `bmv` (number): Brain metastasis velocity in new metastases per year, 1 decimal - `risk_group` (string): Farris 2017 group: low (BMV < 4), intermediate (4-13), or high (BMV > 13) - `median_os_months` (number): Published Farris 2017 median overall survival in months after initial distant brain failure for that group - `citation` (object): Farris 2017 citation - `disclaimer` (string): Not-a-device notice ## Example JSON Frozen fixture. Not a live lookup. ```json { "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.", "citation": { "authors": "Farris M, McTyre ER, Cramer CK, et al.", "doi": "10.1016/j.ijrobp.2017.01.201", "id": "farris-2017", "pmid": "28586952", "source": "Int J Radiat Oncol Biol Phys. 2017 May 1;98(1):169-175", "title": "Brain Metastasis Velocity: A Novel Prognostic Metric Predictive of Overall Survival and Freedom From Whole-Brain Radiation Therapy After Distant Brain Failure Following Upfront Radiosurgery Alone" }, "formula": "bmv", "formula_expression": "bmv = new_brain_metastases / years_since_first_srs", "risk_group": "low", "bmv": 3.0, "median_os_months": 12.4, "new_brain_metastases": 3, "years_since_first_srs": 1.0 } ``` ## Errors - HTTP 400 `invalid_new_brain_metastases`: new_brain_metastases must be an integer from 0 to 200 (Farris 2017 cumulative new metastases since first SRS). Returned before settlement; you are not charged. - HTTP 400 `invalid_years_since_srs`: years_since_first_srs must be a number from 0.01 to 30 (Farris 2017 years since first SRS; must be > 0). Returned before settlement; you are not charged. - HTTP 400 `invalid_items`: POST body must be a JSON object with only an items array Returned before settlement; you are not charged. - HTTP 400 `invalid_item_count`: items must be an array of 1 to 25 objects Returned before settlement; you are not charged. - HTTP 400 `invalid_item`: each items entry must be a JSON object Returned before settlement; you are not charged. Shared HTTP 402 and 503: https://magentlab.com/docs/payments ## Related tools - [THRIVE](https://magentlab.com/docs/thrive) — Compute the Flint 2010 THRIVE (Totaled Health Risks in Vascular Events) score from trichotomized age, trichotomized NIHSS, and the chronic disease scale (hypertension, diabetes mellitus, atrial fibrillation). - [ABC/2](https://magentlab.com/docs/abc2) — Compute the Kothari 1996 ABC/2 ellipsoid ICH volume as (a_cm × b_cm × c_cm) / 2 from caller-supplied diameters in centimeters. ## Payment Unpaid requests return HTTP 402 even if query parameters or POST items are missing or invalid, so CDP and agents can index the path. After a PAYMENT-SIGNATURE, invalid params return HTTP 400 JSON before settlement. magent does not charge. Fix the params, then request a new 402 quote for that complete URL. Catalog misses (empty matches, found=false) are valid paid 200s. - GET the tool with Accept: application/json (do not send Accept: text/html unless you want the human paywall). - HTTP 402 means you have not paid. Decode the base64 PAYMENT-REQUIRED header. HTTP 503 is not a new quote. - Sign accepts[0] (exact, EIP-3009) with validBefore = now + maxTimeoutSeconds (600 seconds), or accepts[1] (batch-settlement deposit/voucher) on product GET. Ping and POST {items} stay exact. Magent retries transient facilitator 429/5xx before answering. - Retry the same URL with PAYMENT-SIGNATURE (base64 JSON of accepted and payload). Magent attaches canonical extensions.bazaar on CDP verify/settle; echoing 402 bazaar is optional. - Success is HTTP 200 JSON plus PAYMENT-RESPONSE. exact settles before the tool. batch-settlement verifies (and deposit-settles) before the tool and commits the charge after HTTP 2xx. HTTP 503: retry the same PAYMENT-SIGNATURE. Mint a new exact nonce only after a new HTTP 402. - offered `exact` on eip155:8453: Fixed-price USDC on Base. The buyer authorizes the advertised amount (EIP-3009). magent settles before the tool runs (paymentFlow upfront). extra.assetTransferMethod=eip3009 extra.paymentFlow=upfront. - offered `batch-settlement` on eip155:8453: Payment-channel vouchers claimed later in batches. Exact stays accepts[0]. Same-path POST {items} is still exact. extra.assetTransferMethod=eip3009 extra.paymentFlow=authorization. - not offered `upto`: Not offered. Usage-based: buyer authorizes a ceiling, seller settles the actual amount after work. Reserved for a future metered tool. Not for current calculators or code search. Same-path POST {items} is still scheme exact: one EIP-3009 authorization for GET unit plus $0.002 per extra item. That is not x402 batch-settlement (payment channels / vouchers). Shared HTTP 402 and 503 table: https://magentlab.com/docs/payments Stdio MCP (one process per host): https://magentlab.com/docs/mcp ## Guarantees - HTTP 402 is unpaid, including a missing query. After PAYMENT-SIGNATURE, invalid parameters return HTTP 400 before settlement. You are not charged. HTTP 402 never includes the tool JSON. - exact: settlement finishes before the tool (paymentFlow upfront). batch-settlement: verify/deposit before the tool; chargedCumulativeAmount commits after HTTP 2xx. Uncertain or failed settlement fails closed (HTTP 503). Retry the same PAYMENT-SIGNATURE. - HTTP 402 is unpaid only. Do not sign a second authorization because of a 503. - Execution is timeout-bounded and concurrency-capped. - Calculator inputs are stored encrypted for allowlisted operators (Magent Console). They are not in public logs, SSH lookups, catalog, or rollups. Request logs store path without query.